Science.gov

Sample records for future wide-field optical

  1. The DESI Wide Field Corrector Optics

    SciTech Connect

    Doel, Peter; Sholl, Michael J.; Liang, Ming; Brooks, David; Flaugher, Brenna; Gutierrez, Gaston; Kent, Stephen; Lampton, Michael; Miller, Timothy; Sprayberry, David

    2014-01-01

    The Dark Energy Spectroscopic instrument (DESI) is a 5000 fiber multi-object spectrometer system under development for installation on the National Optical Astronomy Observatory (NOAO) Kitt Peak 4m telescope (the Mayall telescope). DESI is designated to perform a 14,000° (square) galaxy and Quasi-Stellar Object (QSO) redshift survey to improve estimates of the dark energy equation of state. The survey design imposes numerous constraints on a prime focus corrector design, including field of view, geometrical blur, stability, fiber injection efficiency, zenith angle, mass and coast. The DESI baseline wide-field optical design described herein provides a 3.2 diameter field of view with six 0.8-1.14m diameter lenses and an integral atmospheric dispersion compensator.

  2. Adaptive wide-field optical tomography

    NASA Astrophysics Data System (ADS)

    Venugopal, Vivek; Intes, Xavier

    2013-03-01

    We describe a wide-field optical tomography technique, which allows the measurement-guided optimization of illumination patterns for enhanced reconstruction performances. The iterative optimization of the excitation pattern aims at reducing the dynamic range in photons transmitted through biological tissue. It increases the number of measurements collected with high photon counts resulting in a dataset with improved tomographic information. Herein, this imaging technique is applied to time-resolved fluorescence molecular tomography for preclinical studies. First, the merit of this approach is tested by in silico studies in a synthetic small animal model for typical illumination patterns. Second, the applicability of this approach in tomographic imaging is validated in vitro using a small animal phantom with two fluorescent capillaries occluded by a highly absorbing inclusion. The simulation study demonstrates an improvement of signal transmitted (˜2 orders of magnitude) through the central portion of the small animal model for all patterns considered. A corresponding improvement in the signal at the emission wavelength by 1.6 orders of magnitude demonstrates the applicability of this technique for fluorescence molecular tomography. The successful discrimination and localization (˜1 mm error) of the two objects with higher resolution using the optimized patterns compared with nonoptimized illumination establishes the improvement in reconstruction performance when using this technique.

  3. Wide field strip-imaging optical system

    NASA Technical Reports Server (NTRS)

    Vaughan, Arthur H. (Inventor)

    1994-01-01

    A strip imaging wide angle optical system is provided. The optical system is provided with a 'virtual' material stop to avoid aberrational effects inherent in wide angle optical systems. The optical system includes a spherical mirror section for receiving light from a 180-degree strip or arc of a target image. Light received by the spherical mirror section is reflected to a frusto-conical mirror section for subsequent rereflection to a row of optical fibers. Each optical fiber transmits a portion of the received light to a detector. The optical system exploits the narrow cone of acceptance associated with optical fibers to substantially eliminate vignetting effects inherent in wide-angle systems. Further, the optical system exploits the narrow cone of acceptance of the optical fibers to substantially limit spherical aberration. The optical system is ideally suited for any application wherein a 180-degree strip image need be detected, and is particularly well adapted for use in hostile environments such as in planetary exploration.

  4. Optical Design of WFIRST-AFTA Wide-Field Instrument

    NASA Technical Reports Server (NTRS)

    Pasquale, Bert; Content, Dave; Kruk, Jeffrey; Vaughn, David; Gong, Qian; Howard, Joseph; Jurling, Alden; Mentzell, Eric; Armani, Nerses; Kuan, Gary

    2014-01-01

    The WFIRSTAFTA Wide-Field Infrared Survey Telescope TMA optical design provides 0.28-sq FOV at 0.11 pixel scale, operating between 0.6 2.4m, including a spectrograph mode (1.3-1.95m.) An IFU provides a discrete 3x3.15 field at 0.15 sampling.

  5. Optical design study of the Wide Field Survey Telescope (WFST)

    NASA Astrophysics Data System (ADS)

    Lou, Zheng; Liang, Ming; Yao, Dazhi; Zheng, Xianzhong; Cheng, Jingquan; Wang, Hairen; Liu, Wei; Qian, Yuan; Zhao, Haibin; Yang, Ji

    2016-10-01

    WFST is a proposed 2.5m wide field survey telescope intended for dedicated wide field sciences. The telescope is to operate at six wavelength bands (u, g, r, i, z, and w), spanning from 320 to 1028 nm. Designed with a field of view diameter of 3 degree and an effective aperture diameter of 2.29 m, the WFST acquires a total optical throughput over 29.3 m2deg2. With such a large throughput, WFST will survey up to 6000deg2 of the northern sky in multiple colors each night, reaching 23th magnitude for high-precision photometry and astrometry. The optical design is based on an advanced primary-focus system made up of a 2.5 m f/2.48 concave primary mirror and a primary-focus assembly (PFA) consisting of five corrector lenses, atmospheric dispersion corrector (ADC), filters, and the focal-plane instrument. For zenith angles from 0 to 60 degrees, 80% of the polychromatic diffracted energy falls within a 0.35 arcsec diameter. The optical design also highlights an enhanced transmission in the UV bands. The total optical transmission reaches 23.5% at 320 nm, allowing unique science goals in the U band. Other features include low distortion and ease of baffling against stray lights, etc. The focal-plane instrument is a 0.9 gigapixel mosaic CCD camera comprising 9 pieces of 10K×10K CCD chips. An active optics system (AOS) is used to maintain runtime image quality. Various design aspects of the WFST including the optical design, active optics, mirror supports, and the focal-plane instrument are discussed in detail.

  6. Wide field of view adaptive optical system for lightweight deployable telescope technologies

    NASA Astrophysics Data System (ADS)

    McComas, Brian K.; Cermak, Michael A.; Friedman, Edward J.

    2003-02-01

    A NASA research contract (NAS1-00116) was awarded to Ball Aerospace & Technologies Corp. in January 2000 to study wide field-of-view adaptive optical systems. These systems will be required on future high resolution Earth remote sensing systems that employ large, flexible, lightweight, deployed primary mirrors. The deformations from these primary mirrors will introduce aberrations into the optical system, which must be removed by corrective optics. For economic reasons, these remote sensing systems must have a large field-of-view (a few degrees). Unlike ground-based adaptive optical systems, which have a negligible field-of-view, the adaptive optics on these space-based remote sensing systems will be required to correct for the deformations in the primary mirror over the entire field-of-view. A new error function, which is an enhancement to conventional adaptive optics, for wide field-of-view optical systems will be introduced. This paper will present the goals of the NASA research project and its progress. The initial phase of this research project is a demonstration of the wide field-of-view adaptive optics theory. A breadboard has been designed and built for this purpose. The design and assembly of the breadboard will be presented, along with the final results for this phase of the research project. Finally, this paper will show the applicability of wide field-of-view adaptive optics to space-based astronomical systems.

  7. Experience with wavefront sensor and deformable mirror interfaces for wide-field adaptive optics systems

    NASA Astrophysics Data System (ADS)

    Basden, A. G.; Atkinson, D.; Bharmal, N. A.; Bitenc, U.; Brangier, M.; Buey, T.; Butterley, T.; Cano, D.; Chemla, F.; Clark, P.; Cohen, M.; Conan, J.-M.; de Cos, F. J.; Dickson, C.; Dipper, N. A.; Dunlop, C. N.; Feautrier, P.; Fusco, T.; Gach, J. L.; Gendron, E.; Geng, D.; Goodsell, S. J.; Gratadour, D.; Greenaway, A. H.; Guesalaga, A.; Guzman, C. D.; Henry, D.; Holck, D.; Hubert, Z.; Huet, J. M.; Kellerer, A.; Kulcsar, C.; Laporte, P.; Le Roux, B.; Looker, N.; Longmore, A. J.; Marteaud, M.; Martin, O.; Meimon, S.; Morel, C.; Morris, T. J.; Myers, R. M.; Osborn, J.; Perret, D.; Petit, C.; Raynaud, H.; Reeves, A. P.; Rousset, G.; Sanchez Lasheras, F.; Sanchez Rodriguez, M.; Santos, J. D.; Sevin, A.; Sivo, G.; Stadler, E.; Stobie, B.; Talbot, G.; Todd, S.; Vidal, F.; Younger, E. J.

    2016-06-01

    Recent advances in adaptive optics (AO) have led to the implementation of wide field-of-view AO systems. A number of wide-field AO systems are also planned for the forthcoming Extremely Large Telescopes. Such systems have multiple wavefront sensors of different types, and usually multiple deformable mirrors (DMs). Here, we report on our experience integrating cameras and DMs with the real-time control systems of two wide-field AO systems. These are CANARY, which has been operating on-sky since 2010, and DRAGON, which is a laboratory AO real-time demonstrator instrument. We detail the issues and difficulties that arose, along with the solutions we developed. We also provide recommendations for consideration when developing future wide-field AO systems.

  8. Data Reduction Algorithm for Optical Wide Field Patrol (OWL)

    NASA Astrophysics Data System (ADS)

    Park, S.; Park, Y.; Yim, H.; Jo, J.; Moon, H.; Bae, Y.; Lim, Y.; Choi, J.; Choi, Y.; Park, J.; Son, J.

    2014-09-01

    OWL (Optical Wide-field Patrol) has a detector system which has the chopper which consists of 4 blades in front of the CCD camera to acquire efficiently the position and time information of moving objects such as artificial satellites. Using this system, it is possible to get more position data by splitting the streaks of the moving object into many pieces with fast rotating blades during tracking. At the same time, the time data of the rotating chopper can be acquired by the time tagger connected to the photo diode. In order to derive the orbits of the targets, we need a sequential data reduction procedure including the calculation of WCS (World Coordinate System) solution to transform the positions into equatorial coordinate systems, and the combination of the time data from the time tagger and the position data. We present such a data reduction procedure and the preliminary results after applying this procedure to the observation images.

  9. Wide-Field Optic for Autonomous Acquisition of Laser Link

    NASA Technical Reports Server (NTRS)

    Page, Norman A.; Charles, Jeffrey R.; Biswas, Abhijit

    2011-01-01

    An innovation reported in Two-Camera Acquisition and Tracking of a Flying Target, NASA Tech Briefs, Vol. 32, No. 8 (August 2008), p. 20, used a commercial fish-eye lens and an electronic imaging camera for initially locating objects with subsequent handover to an actuated narrow-field camera. But this operated against a dark-sky background. An improved solution involves an optical design based on custom optical components for the wide-field optical system that directly addresses the key limitations in acquiring a laser signal from a moving source such as an aircraft or a spacecraft. The first challenge was to increase the light collection entrance aperture diameter, which was approximately 1 mm in the first prototype. The new design presented here increases this entrance aperture diameter to 4.2 mm, which is equivalent to a more than 16 times larger collection area. One of the trades made in realizing this improvement was to restrict the field-of-view to +80 deg. elevation and 360 azimuth. This trade stems from practical considerations where laser beam propagation over the excessively high air mass, which is in the line of sight (LOS) at low elevation angles, results in vulnerability to severe atmospheric turbulence and attenuation. An additional benefit of the new design is that the large entrance aperture is maintained even at large off-axis angles when the optic is pointed at zenith. The second critical limitation for implementing spectral filtering in the design was tackled by collimating the light prior to focusing it onto the focal plane. This allows the placement of the narrow spectral filter in the collimated portion of the beam. For the narrow band spectral filter to function properly, it is necessary to adequately control the range of incident angles at which received light intercepts the filter. When this angle is restricted via collimation, narrower spectral filtering can be implemented. The collimated beam (and the filter) must be relatively large to

  10. Deriving comprehensive error breakdown for wide field adaptive optics systems using end-to-end simulations

    NASA Astrophysics Data System (ADS)

    Ferreira, F.; Gendron, E.; Rousset, G.; Gratadour, D.

    2016-07-01

    The future European Extremely Large Telescope (E-ELT) adaptive optics (AO) systems will aim at wide field correction and large sky coverage. Their performance will be improved by using post processing techniques, such as point spread function (PSF) deconvolution. The PSF estimation involves characterization of the different error sources in the AO system. Such error contributors are difficult to estimate: simulation tools are a good way to do that. We have developed in COMPASS (COMputing Platform for Adaptive opticS Systems), an end-to-end simulation tool using GPU (Graphics Processing Unit) acceleration, an estimation tool that provides a comprehensive error budget by the outputs of a single simulation run.

  11. Telescope with a wide field of view internal optical scanner

    NASA Technical Reports Server (NTRS)

    Degnan, III, John James (Inventor); Zheng, Yunhui (Inventor)

    2012-01-01

    A telescope with internal scanner utilizing either a single optical wedge scanner or a dual optical wedge scanner and a controller arranged to control a synchronous rotation of the first and/or second optical wedges, the wedges constructed and arranged to scan light redirected by topological surfaces and/or volumetric scatterers. The telescope with internal scanner further incorporates a first converging optical element that receives the redirected light and transmits the redirected light to the scanner, and a second converging optical element within the light path between the first optical element and the scanner arranged to reduce an area of impact on the scanner of the beam collected by the first optical element.

  12. Wide field/planetary camera optics study. [for the large space telescope

    NASA Technical Reports Server (NTRS)

    1979-01-01

    Design feasibility of the baseline optical design concept was established for the wide field/planetary camera (WF/PC) and will be used with the space telescope (ST) to obtain high angular resolution astronomical information over a wide field. The design concept employs internal optics to relay the ST image to a CCD detector system. Optical design performance predictions, sensitivity and tolerance analyses, manufacturability of the optical components, and acceptance testing of the two mirror Cassegrain relays are discussed.

  13. Plastic optical fiber for wide field-of-view optical wireless receiver

    NASA Astrophysics Data System (ADS)

    Fallah, Hoorieh; Sterckx, Karel; Saengudomlert, Poompat; Mohammed, Waleed S.

    2016-10-01

    This paper demonstrates a working indoor optical wireless link for smart environment applications. The system utilizes a wide field-of-view (FOV) optical wireless receiver through cleaving the tip of large core plastic optical fibers (POFs) attached to the detector. The quality of the optical link is quantified through bit error rate (BER) measurements. The experimental results show a wide FOV with the uncoded BER in the order of 10-3 for transmission distances up to 35 cm when using two POFs for signal collection. The distance can be improved further by increasing the number of fibers. The transmitted signal format and how the BER measurement is achieved are discussed at length. In addition, details are provided for the design of the electronics to establish the optical wireless link.

  14. Three dimensional image reconstruction based on a wide-field optical coherence tomography system

    NASA Astrophysics Data System (ADS)

    Feng, Yinqi; Feng, Shengtong; Zhang, Min; Hao, Junjun

    2014-07-01

    Wide-field optical coherence tomography has a promising application for its high scanning rate and resolution. The principle of a wide-field optical coherence tomography system is described, and 2D images of glass slides are reconstructed using eight-stepped phase-shifting method in the system. Using VC6.0 and OpenGL programming, 3D images are reconstructed based on the Marching Cube algorithm with 2D image sequences. The experimental results show that the depth detection and three-dimensional tomography for translucent materials could be implemented efficiently in the WFOCT system.

  15. Wide-field monitoring strategy for the study of fast optical transients

    NASA Astrophysics Data System (ADS)

    Beskin, Grigory; Bondar, Sergey; Karpov, Sergey; Guarnieri, Adriano; Bartolini, Corrado; Greco, Giuseppe; Piccioni, Adalberto

    2010-10-01

    We discuss the strategy of search for fast optical transients accompanying gamma-ray bursts by means of continuous monitoring of wide sky fields with high temporal resolution. We describe the design, performance and results of our cameras, FAVOR and TORTORA. Also we discuss the perspectives of this strategy and possible design of next-generation equipment for wide-field monitoring which will be able to detect optical transients and to study their color and polarization properties with high time resolution.

  16. An Overview of Wide-Field-Of-View Optical Designs for Survey Telescopes

    DTIC Science & Technology

    2010-09-01

    exist with each having its own strengths and limitations. 1. Introduction Wide-field astronomical sky survey work dates back to the mid 1840s...shortly after the invention of photography [1]. Early survey instruments were nothing more than cameras and the optics were early camera lenses...Some of the better known optics were made by Voigtlander and Petzval [2]. As the technical characteristics of photography improved, larger

  17. Ground-based complex for detection and investigation of fast optical transients in wide field

    NASA Astrophysics Data System (ADS)

    Molinari, Emilio; Beskin, Grigory; Bondar, Sergey; Karpov, Sergey; Plokhotnichenko, Vladimir; de-Bur, Vjacheslav; Greco, Guiseppe; Bartolini, Corrado; Guarnieri, Adriano; Piccioni, Adalberto

    2008-07-01

    To study short stochastic optical flares of different objects (GRBs, SNs, etc) of unknown localizations as well as NEOs it is necessary to monitor large regions of sky with high time resolution. We developed a system which consists of wide-field camera (FOW is 400-600 sq.deg.) using TV-CCD with time resolution of 0.13 s to record and classify optical transients, and a fast robotic telescope aimed to perform their spectroscopic and photometric investigation just after detection. Such two telescope complex TORTOREM combining wide-field camera TORTORA and robotic telescope REM operated from May 2006 at La Silla ESO observatory. Some results of its operation, including first fast time resolution study of optical transient accompanying GRB and discovery of its fine time structure, are presented. Prospects for improving the complex efficiency are given.

  18. Adaptive optics scanning laser ophthalmoscope with integrated wide-field retinal imaging and tracking.

    PubMed

    Ferguson, R Daniel; Zhong, Zhangyi; Hammer, Daniel X; Mujat, Mircea; Patel, Ankit H; Deng, Cong; Zou, Weiyao; Burns, Stephen A

    2010-11-01

    We have developed a new, unified implementation of the adaptive optics scanning laser ophthalmoscope (AOSLO) incorporating a wide-field line-scanning ophthalmoscope (LSO) and a closed-loop optical retinal tracker. AOSLO raster scans are deflected by the integrated tracking mirrors so that direct AOSLO stabilization is automatic during tracking. The wide-field imager and large-spherical-mirror optical interface design, as well as a large-stroke deformable mirror (DM), enable the AOSLO image field to be corrected at any retinal coordinates of interest in a field of >25 deg. AO performance was assessed by imaging individuals with a range of refractive errors. In most subjects, image contrast was measurable at spatial frequencies close to the diffraction limit. Closed-loop optical (hardware) tracking performance was assessed by comparing sequential image series with and without stabilization. Though usually better than 10 μm rms, or 0.03 deg, tracking does not yet stabilize to single cone precision but significantly improves average image quality and increases the number of frames that can be successfully aligned by software-based post-processing methods. The new optical interface allows the high-resolution imaging field to be placed anywhere within the wide field without requiring the subject to re-fixate, enabling easier retinal navigation and faster, more efficient AOSLO montage capture and stitching.

  19. Scalable wide-field optical coherence tomography-based angiography for in vivo imaging applications

    PubMed Central

    Xu, Jingjiang; Wei, Wei; Song, Shaozhen; Qi, Xiaoli; Wang, Ruikang K.

    2016-01-01

    Recent advances in optical coherence tomography (OCT)-based angiography have demonstrated a variety of biomedical applications in the diagnosis and therapeutic monitoring of diseases with vascular involvement. While promising, its imaging field of view (FOV) is however still limited (typically less than 9 mm2), which somehow slows down its clinical acceptance. In this paper, we report a high-speed spectral-domain OCT operating at 1310 nm to enable wide FOV up to 750 mm2. Using optical microangiography (OMAG) algorithm, we are able to map vascular networks within living biological tissues. Thanks to 2,048 pixel-array line scan InGaAs camera operating at 147 kHz scan rate, the system delivers a ranging depth of ~7.5 mm and provides wide-field OCT-based angiography at a single data acquisition. We implement two imaging modes (i.e., wide-field mode and high-resolution mode) in the OCT system, which gives highly scalable FOV with flexible lateral resolution. We demonstrate scalable wide-field vascular imaging for multiple finger nail beds in human and whole brain in mice with skull left intact at a single 3D scan, promising new opportunities for wide-field OCT-based angiography for many clinical applications. PMID:27231630

  20. Concerning the Development of the Wide-Field Optics for WFXT Including Methods of Optimizing X-Ray Optical Prescriptions for Wide-Field Applications

    NASA Technical Reports Server (NTRS)

    Weisskopf, M. C.; Elsner, R. F.; O'Dell, S. L.; Ramsey, B. D.

    2010-01-01

    We present a progress report on the various endeavors we are undertaking at MSFC in support of the Wide Field X-Ray Telescope development. In particular we discuss assembly and alignment techniques, in-situ polishing corrections, and the results of our efforts to optimize mirror prescriptions including polynomial coefficients, relative shell displacements, detector placements and tilts. This optimization does not require a blind search through the multi-dimensional parameter space. Under the assumption that the parameters are small enough so that second order expansions are valid, we show that the performance at the detector can be expressed as a quadratic function with numerical coefficients derived from a ray trace through the underlying Wolter I optic. The optimal values for the parameters are found by solving the linear system of equations creating by setting derivatives of this function with respect to each parameter to zero.

  1. Supernova and optical transient observations using the three wide-field telescope array of the KMTNet

    NASA Astrophysics Data System (ADS)

    Moon, Dae-Sik; Kim, Sang Chul; Lee, Jae-Joon; Pak, Mina; Park, Hong Soo; He, Matthias Y.; Antoniadis, John; Ni, Yuan Qi; Lee, Chung-Uk; Kim, Seung-Lee; Park, Byeong-Gon; Kim, Dong-Jin; Cha, Sang-Mok; Lee, Yongseok; Gonzalez, Santiago

    2016-08-01

    The Korea Microlensing Telescope Network (KMTNet) is a network of three new 1.6-m, wide-field telescopes spread over three different sites in Chile, South Africa and Australia. Each telescope is equipped with a four square degree wide-field CCD camera, making the KMTNet an ideal facility for discovering and monitoring early supernovae and other rapidly evolving optical transients by providing 24-hour continuous sky coverage. We describe our inaugurating program of observing supernovae and optical transients using about 20% of the KMTNet time in 2015-2019. Our early results include detection of infant supernovae, novae and peculiar transients as well as numerous variable stars and low surface brightness objects such as dwarf galaxies.

  2. About using wide field lens optics for Space Surveillance Systems in Odessa Astronomical observatory (Ukraine)

    NASA Astrophysics Data System (ADS)

    Sukhov, P. P.; Volkoff, S. K.; Karpenko, G. F.; Titenko, V. V.; Yamnitsky, V. A.; Tkachenko, A. A.

    2007-08-01

    On base results of the observations in Odessa astronomical observatory, is shown obvious fact. The possibility of the using domestic wide field lens optics for monitoring high orbital artificial Earth satellite objects for the calculations elements of orbits. With wide field lens optics "Tair-19 5003", limited magnitude consist 15m.5 per 10 seconds of the accumulation, average square-error (ASE) of the measurements of the coordinates slowly move GSS consist not more than 2 arcsec. Beside 90% measurements has ASE not more 1 arcsec. At surveillance of the area of the equator by width 5° areas 500 deg2 are discovered all 40 active "standing" GSS, 12 passive GSS and 2 high elliptical orbital satellites (HEO). Is shown perspective possibility of the use WFO for monitoring LEO height before of 2 000 km. 90% of 39 object LEO fixed in mode "beam-park" (the still telescope) in current 1 hour, surelay are identified using catalog NORAD.

  3. Application of a wide-field phantom eye for optical coherence tomography and reflectance imaging

    NASA Astrophysics Data System (ADS)

    Corcoran, Anthony; Muyo, Gonzalo; van Hemert, Jano; Gorman, Alistair; Harvey, Andrew R.

    2015-12-01

    Optical coherence tomography (OCT) and reflectance imaging are used in clinical practice to measure the thickness and transverse dimensions of retinal features. The recent trend towards increasing the field of view (FOV) of these devices has led to an increasing significance of the optical aberrations of both the human eye and the device. We report the design, manufacture and application of the first phantom eye that reproduces the off-axis optical characteristics of the human eye, and allows the performance assessment of wide-field ophthalmic devices. We base our design and manufacture on the wide-field schematic eye, [Navarro, R. J. Opt. Soc. Am. A, 1985, 2.] as an accurate proxy to the human eye and enable assessment of ophthalmic imaging performance for a ? external FOV. We used multi-material 3D-printed retinal targets to assess imaging performance of the following ophthalmic instruments: the Optos 200Tx, Heidelberg Spectralis, Zeiss FF4 fundus camera and Optos OCT SLO and use the phantom to provide an insight into some of the challenges of wide-field OCT.

  4. Application of a wide-field phantom eye for optical coherence tomography and reflectance imaging.

    PubMed

    Corcoran, Anthony; Muyo, Gonzalo; van Hemert, Jano; Gorman, Alistair; Harvey, Andrew R

    2015-12-15

    Optical coherence tomography (OCT) and reflectance imaging are used in clinical practice to measure the thickness and transverse dimensions of retinal features. The recent trend towards increasing the field of view (FOV) of these devices has led to an increasing significance of the optical aberrations of both the human eye and the device. We report the design, manufacture and application of the first phantom eye that reproduces the off-axis optical characteristics of the human eye, and allows the performance assessment of wide-field ophthalmic devices. We base our design and manufacture on the wide-field schematic eye, [Navarro, R. J. Opt. Soc. Am. A, 1985,2.] as an accurate proxy to the human eye and enable assessment of ophthalmic imaging performance for a [Formula: see text] external FOV. We used multi-material 3D-printed retinal targets to assess imaging performance of the following ophthalmic instruments: the Optos 200Tx, Heidelberg Spectralis, Zeiss FF4 fundus camera and Optos OCT SLO and use the phantom to provide an insight into some of the challenges of wide-field OCT.

  5. Wide-field optical mapping of neural activity and brain haemodynamics: considerations and novel approaches

    PubMed Central

    Ma, Ying; Shaik, Mohammed A.; Kozberg, Mariel G.; Thibodeaux, David N.; Zhao, Hanzhi T.; Yu, Hang

    2016-01-01

    Although modern techniques such as two-photon microscopy can now provide cellular-level three-dimensional imaging of the intact living brain, the speed and fields of view of these techniques remain limited. Conversely, two-dimensional wide-field optical mapping (WFOM), a simpler technique that uses a camera to observe large areas of the exposed cortex under visible light, can detect changes in both neural activity and haemodynamics at very high speeds. Although WFOM may not provide single-neuron or capillary-level resolution, it is an attractive and accessible approach to imaging large areas of the brain in awake, behaving mammals at speeds fast enough to observe widespread neural firing events, as well as their dynamic coupling to haemodynamics. Although such wide-field optical imaging techniques have a long history, the advent of genetically encoded fluorophores that can report neural activity with high sensitivity, as well as modern technologies such as light emitting diodes and sensitive and high-speed digital cameras have driven renewed interest in WFOM. To facilitate the wider adoption and standardization of WFOM approaches for neuroscience and neurovascular coupling research, we provide here an overview of the basic principles of WFOM, considerations for implementation of wide-field fluorescence imaging of neural activity, spectroscopic analysis and interpretation of results. This article is part of the themed issue ‘Interpreting BOLD: a dialogue between cognitive and cellular neuroscience’. PMID:27574312

  6. Wide-field optical coherence tomography based microangiography for retinal imaging

    PubMed Central

    Zhang, Qinqin; Lee, Cecilia S.; Chao, Jennifer; Chen, Chieh-Li; Zhang, Thomas; Sharma, Utkarsh; Zhang, Anqi; Liu, Jin; Rezaei, Kasra; Pepple, Kathryn L.; Munsen, Richard; Kinyoun, James; Johnstone, Murray; Van Gelder, Russell N.; Wang, Ruikang K.

    2016-01-01

    Optical coherence tomography angiography (OCTA) allows for the evaluation of functional retinal vascular networks without a need for contrast dyes. For sophisticated monitoring and diagnosis of retinal diseases, OCTA capable of providing wide-field and high definition images of retinal vasculature in a single image is desirable. We report OCTA with motion tracking through an auxiliary real-time line scan ophthalmoscope that is clinically feasible to image functional retinal vasculature in patients, with a coverage of more than 60 degrees of retina while still maintaining high definition and resolution. We demonstrate six illustrative cases with unprecedented details of vascular involvement in retinal diseases. In each case, OCTA yields images of the normal and diseased microvasculature at all levels of the retina, with higher resolution than observed with fluorescein angiography. Wide-field OCTA technology will be an important next step in augmenting the utility of OCT technology in clinical practice. PMID:26912261

  7. Design of wide-field Nasmyth optical system for a submillimeter camera

    NASA Astrophysics Data System (ADS)

    Tsuzuki, Toshihiro; Nitta, Tom; Imada, Hiroaki; Seta, Masumichi; Nakai, Naomasa; Sekiguchi, Shigeyuki; Sekimoto, Yutaro

    2015-04-01

    A wide-field Nasmyth optical system that connects a planned 10-m Ritchey-Chrétien telescope to a submillimeter camera is reported. This diffraction-limited system has a 1-deg field of view at 850 GHz, filled with a more than 20,000-pixel camera. The system enables us to carry out large field surveys of distant galaxies within reasonable time scales. The size of the Nasmyth optics is reasonably compact and its cryogenic part including the vacuum window, cryogenic lens, and IR block filters can be built using existing technologies at a reasonable cost. This type of optical system can be applied for the optical design of millimeter, terahertz, and other submillimeter instruments.

  8. Wide-field optical sectioning for live-tissue imaging by plane-projection multiphoton microscopy

    NASA Astrophysics Data System (ADS)

    Yu, Jiun-Yann; Kuo, Chun-Hung; Holland, Daniel B.; Chen, Yenyu; Ouyang, Mingxing; Blake, Geoffrey A.; Zadoyan, Ruben; Guo, Chin-Lin

    2011-11-01

    Optical sectioning provides three-dimensional (3D) information in biological tissues. However, most imaging techniques implemented with optical sectioning are either slow or deleterious to live tissues. Here, we present a simple design for wide-field multiphoton microscopy, which provides optical sectioning at a reasonable frame rate and with a biocompatible laser dosage. The underlying mechanism of optical sectioning is diffuser-based temporal focusing. Axial resolution comparable to confocal microscopy is theoretically derived and experimentally demonstrated. To achieve a reasonable frame rate without increasing the laser power, a low-repetition-rate ultrafast laser amplifier was used in our setup. A frame rate comparable to that of epifluorescence microscopy was demonstrated in the 3D imaging of fluorescent protein expressed in live epithelial cell clusters. In this report, our design displays the potential to be widely used for video-rate live-tissue and embryo imaging with axial resolution comparable to laser scanning microscopy.

  9. Enola Gay: an integrated modelling optical toolbox applied to a wide-field telescope

    NASA Astrophysics Data System (ADS)

    Schipani, P.; Perrotta, F.

    2008-07-01

    The integrated modelling approach is fundamental in telescopes design where it is necessary to merge different disciplines together. This paper describes the integration of optical ray-tracing capabilities within the Matlab computational environment. This approach allows to write automatic procedures to implement a huge number of computations, that are very unpractical to perform in interactive mode by ray tracing software packages. Data produced by computations are stored and automatically analyzed. One of the main benefits from this approach comes from the traceability of the work, that is intrinsically impossible when the optical designer works in interactive mode. The right procedure is built and tuned just the first time and the computation software is available for inspection and check. Furthermore computations and results are easily reproducible simply re-running Matlab scripts. An automatic approach is especially helpful in wide-field telescope projects where the optical quality has to be studied over a wide field of view. This leads to repeat the same computations many times in a number of fields. In interactive mode this would cause a significant waste of optical designer time to repeat many times the same manual procedures. The solution proposed here allows to save time and prevent occasional mistakes.

  10. Monitoring with high temporal resolution to search for optical transients in the wide field

    NASA Astrophysics Data System (ADS)

    Beskin, Grigory; Bondar, Sergey; Ivanov, Evgeny; Karpov, Sergey; Katkova, Elena; Pozanenko, Alexei; Guarnieri, Adriano; Bartolini, Corrado; Piccioni, Adalberto; Greco, Giuseppe; Molinari, Emilio; Covino, Stefano

    2008-02-01

    In order to detect and investigate short stochastic optical flares from a number of variable astrophysical objects (GRBs, SNs, flare stars, CVs, X-Ray binaries) of unknown localizations as well as near-earth objects (NEOs), both natural and artificial, it is necessary to perform the systematic monitoring of large regions of the sky with high temporal resolution. Here we describe the design of a system able to perform such a task, which consists of a wide-field camera with high time resolution able to detect and classify the transient events on a subsecond time scale, and a fast robotic telescope aimed to perform their detailed investigation. In a last few years we've created the prototype FAVOR wide-field camera, placed at North Caucasus near Russian 6-m telescope, and a complete two-telescope complex TORTOREM, combining TORTORA wide-field camera with REM robotic telescope and placed at La Silla ESO observatory. Its technical parameters and first results of operation are described.

  11. Optically sectioned wide-field fluorescence lifetime imaging endoscopy enabled by structured illumination (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Hinsdale, Taylor; Malik, Bilal H.; Rico-Jimenez, Jose J.; Jo, Javier A.; Maitland, Kristen C.

    2016-03-01

    We present a wide-field fluorescence lifetime imaging (FLIM) system with optical sectioning by structured illumination microscopy (SIM). FLIM measurements were made using a time gated ICCD camera in conjunction with a pulsed nitrogen dye laser operating at 450 nm. Intensity images were acquired at multiple time delays from a trigger initiated by a laser pulse to create a wide-field FLIM image, which was then combined with three phase SIM to provide optical sectioning. Such a mechanism has the potential to increase the reliability and accuracy of the FLIM measurements by rejecting background intensity. SIM also provides the opportunity to create volumetric FLIM images with the incorporation of scanning mechanisms for the sample plane. We present multiple embodiments of such a system: one as a free space endoscope and the other as a fiber microendoscope enabled by the introduction of a fiber bundle. Finally, we demonstrate the efficacy of such an imaging system by imaging dyes embedded in a tissue phantom.

  12. Wide-field optical coherence tomography angiography enabled by two repeated measurements of B-scans.

    PubMed

    Wang, Ruikang K; Zhang, Anqi; Choi, Woo June; Zhang, Qinqin; Chen, Chieh-Li; Miller, Andrew; Gregori, Giovanni; Rosenfeld, Philip J

    2016-05-15

    Optical coherence tomography angiography (OCTA) has increasingly become clinically important, particularly in ophthalmology. However, the field of view (FOV) for current OCTA imaging is severely limited due to A-scan rates that can be afforded by current clinical systems and, more importantly, the requirement of a repeated scanning protocol. This Letter evaluates the possibility of using only two repeated B-scans for OCTA for the purpose of an increased FOV. The effect of repeated numbers on the OCTA result is discussed through experiments on an animal model in vivo and evaluated using quantitative metrics for image quality. Demonstrated through in vivo imaging of a pathological human eye, we show that optical microangiography-based OCTA with two repeated B-scans can provide wide-field angiography up to 12×12  mm with clinically acceptable image quality.

  13. Optical wide field monitor AROMA-W using multiple digital single-lens reflex cameras

    NASA Astrophysics Data System (ADS)

    Takahashi, Ichiro; Tsunashima, Kosuke; Tatsuhito, Takeda; Saori, Ono; Kazutaka, Yamaoka; Yoshida, Atsumasa

    2010-12-01

    We have developed and operated the automatic optical observation device Aoyama Gakuin University Robotic Optical Monitor for Astrophysical objects - Wide field (AROMA-W). It covers a large field of view of about 45 degrees W 30 degrees at a time by the multiple digital single-lens reflex cameras, and provides photometric data in four bands with a limiting V magnitude of about 12-13 magnitude (20 seconds, 3 sigma level). The automatic analysis pipeline which can analyze in parallel with observation has been constructed so far. It can draw the light curves of all stars in the field of view of AROMA-W. We are aiming at the simultaneous observation of the transients (e.g., X-ray nova, Supernova, GRB) that MAXI discovered by using the AROMA-W. We report the developmental status, the observational results of AROMA-W and a possibility of the simultaneous observation to the X-ray transients discovered with MAXI.

  14. Progress Report on Optimizing X-ray Optical Prescriptions for Wide-Field Applications

    NASA Technical Reports Server (NTRS)

    Elsner, R. F.; O'Dell, S. L.; Ramsey, B. D.; Weisskopf, M. C.

    2011-01-01

    We report on the present status of our continuing efforts to develop a method for optimizing wide-field nested x-ray telescope mirror prescriptions. Utilizing extensive Monte-Carlo ray trace simulations, we find an analytic form for the root-mean-square dispersion of rays from a Wolter I optic on the surface of a flat focal plane detector as a function of detector tilt away from the nominal focal plane and detector displacement along the optical axis. The configuration minimizing the ray dispersion from a nested array of Wolter I telescopes is found by solving a linear system of equations for tilt and individual mirror pair displacement. Finally we outline our initial efforts at expanding this method to include higher order polynomial terms in the mirror prescriptions.

  15. Proto-Type Development of Optical Wide-field Patrol Network and Test Observation

    NASA Astrophysics Data System (ADS)

    Park, J.; Choi, Y.; Jo, J.; Moon, H.; Yim, H.; Park, Y.; Hae, Y.; Park, S.; Choi, J.; Son, J.

    2014-09-01

    We present a prototype system developed for optical satellite tracking and its early test observation results. The main objective of the OWL (Optical Wide-field patroL) network is to get orbital information for Korean domestic satellites using optical means only and to maintain their orbital elements. The network is composed of 5 small wide-field telescopes deployed over the world. Each observing station is operated in fully robotic manner from receiving observation schedule to reporting the result, and controlled by the headquarter located in Daejeon, Korea, where orbit calculation and observation strategy will be determined. We developed a compact telescope system for robotic observation and easy maintenance. The telescope is 0.5m of aperture diameter with Rechey-Cretian configuration and its field of view is 1.1 deg. It is equipped with 4K CCD with 9um pixel size, and its pixel scale is 1.2 arcsec/pixel. A chopper wheel with variable speed is adopted to get more points in a single shot. The CCD camera and all the rotating parts (chopper wheel, de-rotator, and filter wheel) are integrated into one compact component called a wheel station. Each observing station is equipped with a fully automatic dome and heavy duty environment monitoring system. We could get an image every 20 seconds and up to ~100 trail points in a single exposure. Each point is time-tagged by ~1/1000 second precision. For one of best cases, we could estimate satellite position with RMS ~ 0.5km accuracy in the along-track with only 4 exposures (~100 points). The first system was installed at the Mongolian site after completing verification test at the testbed site in Daejeon, Korea. The second and third system will be installed in the end of this year.

  16. Wide-field and high-resolution optical imaging for early detection of oral neoplasia

    NASA Astrophysics Data System (ADS)

    Pierce, Mark C.; Schwarz, Richard A.; Rosbach, Kelsey; Roblyer, Darren; Muldoon, Tim; Williams, Michelle D.; El-Naggar, Adel K.; Gillenwater, Ann M.; Richards-Kortum, Rebecca

    2010-02-01

    Current procedures for oral cancer screening typically involve visual inspection of the entire tissue surface at risk under white light illumination. However, pre-cancerous lesions can be difficult to distinguish from many benign conditions when viewed under these conditions. We have developed wide-field (macroscopic) imaging system which additionally images in cross-polarized white light, narrowband reflectance, and fluorescence imaging modes to reduce specular glare, enhance vascular contrast, and detect disease-related alterations in tissue autofluorescence. We have also developed a portable system to enable high-resolution (microscopic) evaluation of cellular features within the oral mucosa in situ. This system is a wide-field epi-fluorescence microscope coupled to a 1 mm diameter, flexible fiber-optic imaging bundle. Proflavine solution was used to specifically label cell nuclei, enabling the characteristic differences in N/C ratio and nuclear distribution between normal, dysplastic, and cancerous oral mucosa to be quantified. This paper discusses the technical design and performance characteristics of these complementary imaging systems. We will also present data from ongoing clinical studies aimed at evaluating diagnostic performance of these systems for detection of oral neoplasia.

  17. Wide field and highly sensitive angiography based on optical coherence tomography with akinetic swept source

    PubMed Central

    Xu, Jingjiang; Song, Shaozhen; Wei, Wei; Wang, Ruikang K.

    2016-01-01

    Wide-field vascular visualization in bulk tissue that is of uneven surface is challenging due to the relatively short ranging distance and significant sensitivity fall-off for most current optical coherence tomography angiography (OCTA) systems. We report a long ranging and ultra-wide-field OCTA (UW-OCTA) system based on an akinetic swept laser. The narrow instantaneous linewidth of the swept source with its high phase stability, combined with high-speed detection in the system enable us to achieve long ranging (up to 46 mm) and almost negligible system sensitivity fall-off. To illustrate these advantages, we compare the basic system performances between conventional spectral domain OCTA and UW-OCTA systems and their functional imaging of microvascular networks in living tissues. In addition, we show that the UW-OCTA is capable of different depth-ranging of cerebral blood flow within entire brain in mice, and providing unprecedented blood perfusion map of human finger in vivo. We believe that the UW-OCTA system has promises to augment the existing clinical practice and explore new biomedical applications for OCT imaging. PMID:28101428

  18. WINGS: a WIde-field Nearby Galaxy-cluster Survey. I. Optical imaging

    NASA Astrophysics Data System (ADS)

    Fasano, G.; Marmo, C.; Varela, J.; D'Onofrio, M.; Poggianti, B. M.; Moles, M.; Pignatelli, E.; Bettoni, D.; Kjærgaard, P.; Rizzi, L.; Couch, W. J.; Dressler, A.

    2006-01-01

    This is the first paper of a series that will present data and scientific results from the WINGS project, a wide-field, multiwavelength imaging and spectroscopic survey of galaxies in 77 nearby clusters. The sample was extracted from the ROSAT catalogs of X-Ray emitting clusters, with constraints on the redshift (0.04< z<0.07) and distance from the galactic plane ({\\vert}b{\\vert}≥ 20 deg). The global goal of the WINGS project is the systematic study of the local cosmic variance of the cluster population and of the properties of cluster galaxies as a function of cluster properties and local environment. This data collection will allow the definition of a local, "zero-point" reference against which to gauge the cosmic evolution when compared to more distant clusters. The core of the project consists of wide-field optical imaging of the selected clusters in the B and V bands. We have also completed a multi-fiber, medium-resolution spectroscopic survey for 51 of the clusters in the master sample. The imaging and spectroscopy data were collected using, respectively, the WFC@INT and WYFFOS@WHT in the northern hemisphere, and the WFI@MPG and 2dF@AAT in the southern hemisphere. In addition, a NIR (J, K) survey of ˜50 clusters and an Hα+U survey of some 10 clusters are presently ongoing with the WFCAM@UKIRT and WFC@INT, respectively, while a very-wide-field optical survey has also been programmed with OmegaCam@VST. In this paper we briefly outline the global objectives and the main characteristics of the WINGS project. Moreover, the observing strategy and the data reduction of the optical imaging survey (WINGS-OPT) are presented. We have achieved a photometric accuracy of ˜0.025 mag, reaching completeness to V˜ 23.5. Field size and resolution (FWHM) span the absolute intervals (1.6-2.7) Mpc and (0.7-1.7) kpc, respectively, depending on the redshift and on the seeing. This allows the planned studies to obtain a valuable description of the local properties of clusters

  19. Wide-field optical coherence micro-elastography for intraoperative assessment of human breast cancer margins

    PubMed Central

    Allen, Wes M.; Chin, Lixin; Wijesinghe, Philip; Kirk, Rodney W.; Latham, Bruce; Sampson, David D.; Saunders, Christobel M.; Kennedy, Brendan F.

    2016-01-01

    Incomplete excision of malignant tissue is a major issue in breast-conserving surgery, with typically 20 - 30% of cases requiring a second surgical procedure arising from postoperative detection of an involved margin. We report advances in the development of a new intraoperative tool, optical coherence micro-elastography, for the assessment of tumor margins on the micro-scale. We demonstrate an important step by conducting whole specimen imaging in intraoperative time frames with a wide-field scanning system acquiring mosaicked elastograms with overall dimensions of ~50 × 50 mm, large enough to image an entire face of most lumpectomy specimens. This capability is enabled by a wide-aperture annular actuator with an internal diameter of 65 mm. We demonstrate feasibility by presenting elastograms recorded from freshly excised human breast tissue, including from a mastectomy, lumpectomies and a cavity shaving. PMID:27867721

  20. Methods of Optimizing X-Ray Optical Prescriptions for Wide-Field Applications

    NASA Technical Reports Server (NTRS)

    Elsner, R. F.; O'Dell, S. L.; Ramsey, B. D.; Weisskopf, M. C.

    2010-01-01

    We are working on the development of a method for optimizing wide-field x-ray telescope mirror prescriptions, including polynomial coefficients, mirror shell relative displacements, and (assuming 4 focal plane detectors) detector placement and tilt that does not require a search through the multi-dimensional parameter space. Under the assumption that the parameters are small enough that second order expansions are valid, we show that the performance at the detector surface can be expressed as a quadratic function of the parameters with numerical coefficients derived from a ray trace through the underlying Wolter I optic. The best values for the parameters are found by solving the linear system of equations creating by setting derivatives of this function with respect to each parameter to zero. We describe the present status of this development effort.

  1. A small animal time-resolved optical tomography platform using wide-field excitation

    NASA Astrophysics Data System (ADS)

    Venugopal, Vivek

    Small animal imaging plays a critical role in present day biomedical research by filling an important gap in the translation of research from the bench to the bedside. Optical techniques constitute an emerging imaging modality which have tremendous potential in preclinical applications. Optical imaging methods are capable of non-invasive assessment of the functional and molecular characteristics of biological tissue. The three-dimensional optical imaging technique, referred to as diffuse optical tomography, provides an approach for the whole-body imaging of small animal models and can provide volumetric maps of tissue functional parameters (e.g. blood volume, oxygen saturation etc.) and/or provide 3D localization and quantification of fluorescence-based molecular markers in vivo. However, the complex mathematical reconstruction problem associated with optical tomography and the cumbersome instrumental designs limits its adoption as a high-throughput quantitative whole-body imaging modality in current biomedical research. The development of new optical imaging paradigms is thus necessary for a wide-acceptance of this new technology. In this thesis, the design, development, characterization and optimization of a small animal optical tomography system is discussed. Specifically, the platform combines a highly sensitive time-resolved imaging paradigm with multi-spectral excitation capability and CCD-based detection to provide a system capable of generating spatially, spectrally and temporally dense measurement datasets. The acquisition of such data sets however can take long and translate to often unrealistic acquisition times when using the classical point source based excitation scheme. The novel approach in the design of this platform is the adoption of a wide-field excitation scheme which employs extended excitation sources and in the process allows an estimated ten-fold reduction in the acquisition time. The work described herein details the design of the imaging

  2. Cryogenic Telescope, Scanner, and Imaging Optics for the Wide-field Imaging Survey Explorer (WISE)

    NASA Astrophysics Data System (ADS)

    Schwalm, Mark; Akerstrom, A.; Barry, M.; Guregian, J.; LaMalva, F.; Laquidara, P.; Perron, G.; Sampath, D.; Ugolini, V.

    2006-12-01

    NASA's Wide-field Infrared Survey Explorer (WISE) instrument includes a cryogenic telescope, scanner, and imaging optics module. Component fabrication, mirror polishing, and prototype scanner cryogenic testing are complete for these subassemblies, and assembly is in process. The telescope is a 40 cm aperture reflecting five-mirror imager/collimator relay that provides 8X demagnification, a 47 x 86 arcminute field of regard, and a real exit pupil for scanning. It also provides distortion control to better than one part in a thousand to prevent image blur during internal scanning. A single-axis scan mirror at the exit pupil scans the detectors' field of view across the telescope field of regard, countering the orbital motion and freezing the line of sight during the multi-second exposure period. The imaging optics module is a five-mirror re-imager with dichroic beamsplitters that separate the energy into four infrared channels between 2.8 and 26 microns. All modules operate below 17 Kelvin. The all-reflective system uses aluminum mirrors and metering structures. L-3 Communications SSG-Tinsley is designing and building the telescope, scanner, and imaging optics module under contract to the Space Dynamics Laboratory. WISE is a MIDEX mission within NASA's Explorers Program.

  3. Direct design of two freeform optical surfaces for wide field of view line imaging applications

    NASA Astrophysics Data System (ADS)

    Nie, Yunfeng; Thienpont, Hugo; Duerr, Fabian

    2016-04-01

    In this paper, we propose a multi-fields direct design method aiming to calculate two freeform surfaces with an entrance pupil incorporated for wide field of view on-axis line imaging applications. Both infinite and finite conjugate objectives can be designed with this approach. Since a wide angle imaging system requires more than few discrete perfect imaging points, the multi-fields design approach is based on partial coupling of multiple fields, which guarantees a much more balanced imaging performance over the full field of view. The optical path lengths (OPLs) and image points of numerous off-axis fields are calculated during the procedure, thus very few initial parameters are needed. The procedure to calculate such a freeform lens is explained in detail. We have designed an exemplary monochromatic single lens to demonstrate the functionality of the design method. A rotationally symmetric counterpart following the same specifications is compared in terms of RMS spot radius to demonstrate the clear benefit that freeform lens brings to on-axis line imaging systems. In addition, a practical achromatic wide angle objective is designed by combining our multi-fields design method with classic optical design strategies, serving as a very good starting point for further optimization in a commercial optical design program. The results from the perspective of aberrations plots and MTF values show a very good and well balanced performance over the full field of view.

  4. Preliminary optical design of PANIC, a wide-field infrared camera for CAHA

    NASA Astrophysics Data System (ADS)

    Cárdenas, M. C.; Rodríguez Gómez, J.; Lenzen, R.; Sánchez-Blanco, E.

    2008-07-01

    In this paper, we present the preliminary optical design of PANIC (PAnoramic Near Infrared camera for Calar Alto), a wide-field infrared imager for the Calar Alto 2.2 m telescope. The camera optical design is a folded single optical train that images the sky onto the focal plane with a plate scale of 0.45 arcsec per 18 μm pixel. A mosaic of four Hawaii 2RG of 2k x 2k made by Teledyne is used as detector and will give a field of view of 31.9 arcmin x 31.9 arcmin. This cryogenic instrument has been optimized for the Y, J, H and K bands. Special care has been taken in the selection of the standard IR materials used for the optics in order to maximize the instrument throughput and to include the z band. The main challenges of this design are: to produce a well defined internal pupil which allows reducing the thermal background by a cryogenic pupil stop; the correction of off-axis aberrations due to the large field available; the correction of chromatic aberration because of the wide spectral coverage; and the capability of introduction of narrow band filters (~1%) in the system minimizing the degradation in the filter passband without a collimated stage in the camera. We show the optomechanical error budget and compensation strategy that allows our as built design to met the performances from an optical point of view. Finally, we demonstrate the flexibility of the design showing the performances of PANIC at the CAHA 3.5m telescope.

  5. Dual-Conjugate Adaptive Optics Instrument for Wide-Field Retinal Imaging - Oral Paper

    NASA Astrophysics Data System (ADS)

    Thaung, Jörgen; Owner-Petersen, Mette; Popovic, Zoran

    2008-01-01

    To date only conventional single-conjugate adaptive optics (SCAO) systems are used to correct ocular aberrations. A major shortcoming of SCAO is the severely restricted corrected field of view. This can be solved with multi-conjugate adaptive optics (MCAO), a solution that is costly and gives bulky instruments. Another problem, especially in the study of the human eye, is unwanted light from parasitic source reflections and light from unwanted object regions. We present a dual-conjugate adaptive optics (DCAO) demonstrator that will enable wide field high resolution imaging of the human retina in vivo, implementing five retinal guide stars, two OKO micromachined membrane deformable mirrors; a 15 mm 37 channel pupil conjugate mirror, and a 40 mm 79 channel mirror conjugated to a plane in the vitreous body approximately 3 mm in front of the retina. The AO system runs with a closed-loop measurement wavelength of 835 nm. It incorporates an array of collimator lenses to spatially filter the light from all guide stars using only one adjustable iris, and a single camera to image the Hartmann patterns of multiple reference sources. Optical simulations in Zemax indicate an increase of the retinal isoplanatic patch from a radius of 0.5 degrees using SCAO to approximately 3.5 degrees or more using DCAO. The advantage of this is a clinically useful imaging area that is approximately 50 times the size of an SCAO system. This is corroborated by measurements on a model eye while performing SCAO, ground layer adaptive optics (GLAO), and DCAO correction.

  6. Wide-field lensless fluorescent microscopy using a tapered fiber-optic faceplate on a chip.

    PubMed

    Coskun, Ahmet F; Sencan, Ikbal; Su, Ting-Wei; Ozcan, Aydogan

    2011-09-07

    We demonstrate lensless fluorescent microscopy over a large field-of-view of ~60 mm(2) with a spatial resolution of <4 µm. In this on-chip fluorescent imaging modality, the samples are placed on a fiber-optic faceplate that is tapered such that the density of the fiber-optic waveguides on the top facet is >5 fold larger than the bottom one. Placed on this tapered faceplate, the fluorescent samples are pumped from the side through a glass hemisphere interface. After excitation of the samples, the pump light is rejected through total internal reflection that occurs at the bottom facet of the sample substrate. The fluorescent emission from the sample is then collected by the smaller end of the tapered faceplate and is delivered to an opto-electronic sensor-array to be digitally sampled. Using a compressive sampling algorithm, we decode these raw lensfree images to validate the resolution (<4 µm) of this on-chip fluorescent imaging platform using microparticles as well as labeled Giardia muris cysts. This wide-field lensfree fluorescent microscopy platform, being compact and high-throughput, might provide a valuable tool especially for cytometry, rare cell analysis (involving large area microfluidic systems) as well as for microarray imaging applications.

  7. Segmentation guided registration of wide field-of-view retinal optical coherence tomography volumes

    PubMed Central

    Lezama, José; Mukherjee, Dibyendu; McNabb, Ryan P.; Sapiro, Guillermo; Kuo, Anthony N.; Farsiu, Sina

    2016-01-01

    Patient motion artifacts are often visible in densely sampled or large wide field-of-view (FOV) retinal optical coherence tomography (OCT) volumes. A popular strategy for reducing motion artifacts is to capture two orthogonally oriented volumetric scans. However, due to larger volume sizes, longer acquisition times, and corresponding larger motion artifacts, the registration of wide FOV scans remains a challenging problem. In particular, gaps in data acquisition due to eye motion, such as saccades, can be significant and their modeling becomes critical for successful registration. In this article, we develop a complete computational pipeline for the automatic motion correction and accurate registration of wide FOV orthogonally scanned OCT images of the human retina. The proposed framework utilizes the retinal boundary segmentation as a guide for registration and requires only a minimal transformation of the acquired data to produce a successful registration. It includes saccade detection and correction, a custom version of the optical flow algorithm for dense lateral registration and a linear optimization approach for axial registration. Utilizing a wide FOV swept source OCT system, we acquired retinal volumes of 12 subjects and we provide qualitative and quantitative experimental results to validate the state-of-the-art effectiveness of the proposed technique. The source code corresponding to the proposed algorithm is available online. PMID:28018709

  8. Multiple Observing Modes for Wide-field Optical Surveillance of GEO Space

    NASA Astrophysics Data System (ADS)

    McGraw, J.; Zimmer, P.; Ackermann, M.

    2016-09-01

    Very wide field of view optical sensors with silicon detectors are being used in multiple survey modes by J. T. McGraw and Associates to provide persistent, affordable surveillance of GEO space to faint limiting magnitudes. Examples include:

  9. classical staring mode with typical integration times of seconds provided by multiple co-directed sensors to provide a deep mosaic of tens of square degrees per exposure to faint limiting magnitude
  10. b) step-and-stare observations of several second integration time from which a continuous, overlapped, mosaicked image of GEO space can be provided
  11. time-delay and integrate (TDI) imagery obtained by driving the telescope in declination and stepping the telescope in the E-W direction, which produces repeated, overlapping (if desired), synoptic images of GEO space.
  12. With current 350 mm diameter optics, detection limits for concentrated observations (e.g. "neighborhood watch") detection limits of magnitude 18 are achieved, and for uncued survey the detection limits are fainter than magnitude 16. Each of these techniques can employ multiple telescopes to obtain search rates in excess of 1000 square degrees per hour, allowing complete uncued CONUS GEO surveillance to +/- 15 degrees latitude every two nighttime hours. With appropriate placement, sensors could provide complete coverage of GEO to these limiting magnitudes at the same survey rate. At each step of the development of this unique capability we discuss the fundamental underlying physical principals of optics, detectors, search modes and siting that enable this survey, a valuable adjunct to RF, radar, GEODSS and other optical surveys of GEO space.

  13. Wide-field spectral domain-optical coherence tomography in central serous chorioretinopathy.

    PubMed

    Carrai, Paola; Pichi, Francesco; Bonsignore, Francesco; Ciardella, Antonio P; Nucci, Paolo

    2015-04-01

    The aim the study was to describe wide-field spectral-domain optical coherence tomography morphologic relationships of the vitreous, retina, and choroid in central serous chorioretinopathy (CSCR) eyes. Standardized horizontal, vertical, and two oblique (supertemporal to inferonasal and supranasal to inferotemporal) SD-OCT sections were collected for 40 patient with CSCR. For extramacular imaging, images were obtained from eight locations: (1) nasal to the optic disk, (2) extreme nasal periphery, (3) superior to the superotemporal vascular arcade, (4) extreme superior periphery, (5) inferior to the inferotemporal vascular arcade, (6) extreme inferior periphery, (7) temporal to the macula, and (8) extreme temporal periphery. Wide-angle montage images of OCT from equator to equator were composed with a montaging software. Average subfoveal choroidal thickness was 478 ± 114 µm (range 232-695 µm) at the macular level, 367 ± 94 µm in the superior periphery, 257 ± 103 µm in the inferior periphery, 431 ± 121 and 280 ± 88 µm in the nasal and in the temporal periphery, respectively. Wide-field EDI-OCT revealed a relative thinning of the inner choroidal layer in the periphery, including the small and medium large vessels, which ranged from 86 µm nasally to 120.1 µm superiorly, with a mean of 98.8 ± 13.6 µm. Beneath the thinned inner choroidal layer, hyporeflective lumina, corresponding to the outer choroidal layer, were identified in the periphery of all eyes. The outer choroidal layer thickness ranged from 175.5 µm temporally to 235.5 µm superiorly, with a mean of 217.8 ± 41.4 µm. The novel approach of montaging SD-OCT images to examine relationships between the choroid, retina, and associated structures adjacent to and outside of the macula may have a number of relevant applications in the study of pathologic features of central serous chorioretinopathy.

  14. Optimizing X-Ray Optical Prescriptions for Wide-Field Applications

    NASA Technical Reports Server (NTRS)

    Elsner, R. F.; O'Dell, S. L.; Ramsey, B. D.; Weisskopf, M. C.

    2010-01-01

    X-ray telescopes with spatial resolution optimized over the field of view (FOV) are of special interest for missions, such as WFXT, focused on moderately deep and deep surveys of the x-ray sky, and for solar x-ray observations. Here we report on the present status of an on-going study of the properties of Wolter I and polynominal grazing incidence designs with a view to gain a deeper insight into their properties and simply the design process. With these goals in mind, we present some results in the complementary topics of (1) properties of Wolter I x-ray optics and polynominal x-ray optic ray tracing. Of crucial importance for the design of wide-field x-ray optics is the optimization criteria. Here we have adopted the minimization of a merit function, M, which measures the spatial resolution averaged over the FOV: M= ((integral of d phi) between the limits of 0 and 2 pi) (integral of d theta theta w(theta) sigma square (theta,phi) between the limits of 0 and theta(sub FOV)) (integral of d phi between the limits of 0 and phi/4) (Integral of d theta theta w(theta) between the limits of 0 and theta(sub FOV) where w(theta(sub 1) is a weighting function and Merit function: sigma-square (theta, phi) = summation of (x,y,z) [-<(x,y,z)> (exp 2)] is the spatial variance for a point source on the sky at polar and azimuthal off-axis angles (theta,phi).

  15. TMT-AGE: wide field of regard multi-object adaptive optics for TMT

    NASA Astrophysics Data System (ADS)

    Akiyama, Masayuki; Oya, Shin; Ono, Yoshito H.; Takami, Hideki; Ozaki, Shinobu; Hayano, Yutaka; Iwata, Ikuru; Hane, Kazuhiro; Wu, Tong; Yamamuro, Tomoyasu; Ikeda, Yuji

    2014-07-01

    We introduce current status of the feasibility study on a wide field of regard (FoR) Multi-Object Adaptive Optics (MOAO) system for TMT (TMT-AGE: TMT-Analyzer for Galaxies in the Early universe). MOAO is a system which realize high spatial-resolution observations of multiple objects scattered in a wide FoR. In this study, we put emphasise on the FoR as wide as 10' diameter. The wide FoR is crucial to effectively observe very high-redshift galaxies, which have low surface number density. Simulations of an MOAO system with 8 LGSs show close-to-diffraction-limited correction can be achieved within 5' diameter FoR and moderate AO correction can be achieved within 10' diameter FoR. We discuss overall system design of the wide FoR MOAO system considering the constraint from the stroke of small-size deformable mirror (DM). We also introduce current status of developments of key components of an MOAO system; high-dynamic range wavefront sensor (WFS) and large-stroke small-size DM, and real time computer (RTC) with fast tomographic reconstruction.

  16. Development of a Data Reduction algorithm for Optical Wide Field Patrol

    NASA Astrophysics Data System (ADS)

    Park, Sun-youp; Keum, Kang-Hoon; Lee, Seong-Whan; Jin, Ho; Park, Yung-Sik; Hong-Suh; Jo, Jung Hyun; Moon, Hong-Kyu; Bae, Young-Ho; Choi, Jin; Choi, Young-Jun; Park, Jang-Hyun; Lee, Jung-Ho

    2013-09-01

    The detector subsystem of the Optical Wide-field Patrol (OWL) network efficiently acquires the position and time information of moving objects such as artificial satellites through its chopper system, which consists of 4 blades in front of the CCD camera. Using this system, it is possible to get more position data with the same exposure time by changing the streaks of the moving objects into many pieces with the fast rotating blades during sidereal tracking. At the same time, the time data from the rotating chopper can be acquired by the time tagger connected to the photo diode. To analyze the orbits of the targets detected in the image data of such a system, a sequential procedure of determining the positions of separated streak lines was developed that involved calculating the World Coordinate System (WCS) solution to transform the positions into equatorial coordinate systems, and finally combining the time log records from the time tagger with the transformed position data. We introduce this procedure and the preliminary results of the application of this procedure to the test observation images.

  17. Affordable Wide-field Optical Space Surveillance using sCMOS and GPUs

    NASA Astrophysics Data System (ADS)

    Zimmer, P.; McGraw, J.; Ackermann, M.

    2016-09-01

    Recent improvements in sCMOS technology allow for affordable, wide-field, and rapid cadence surveillance from LEO to out past GEO using largely off-the-shelf hardware. sCMOS sensors, until very recently, suffered from several shortcomings when compared to CCD sensors - lower sensitivity, smaller physical size and less predictable noise characteristics. Sensors that overcome the first two of these are now available commercially and the principals at J.T. McGraw and Associates (JTMA) have developed observing strategies that minimize the impact of the third, while leveraging the key features of sCMOS, fast readout and low average readout noise. JTMA has integrated a new generation sCMOS sensor into an existing COTS telescope system in order to develop and test new detection techniques designed for uncued optical surveillance across a wide range of apparent object angular rates - from degree per second scale of LEO objects to a few arcseconds per second for objects out past GEO. One further complication arises from this: increased useful frame rate means increased data volume. Fortunately, GPU technology continues to advance at a breakneck pace and we report on the results and performance of our new detection techniques implemented on new generation GPUs. Early results show significance within 20% of the expected theoretical limiting signal-to-noise using commodity GPUs in near real time across a wide range of object parameters, closing the gap in detectivity between moving objects and tracked objects.

  18. The wide-field imager for IXO: status and future activities

    NASA Astrophysics Data System (ADS)

    Strüder, Lothar; Aschauer, Florian; Bautz, Mark; Bombelli, Luca; Burrows, David; Fiorini, Carlo; Fraser, George; Herrmann, Sven; Kendziorra, Eckhard; Kuster, Markus; Lauf, Thomas; Lechner, Peter; Lutz, Gerhard; Majewski, Petra; Meuris, Aline; Porro, Matteo; Reiffers, Jonas; Richter, Rainer; Santangelo, Andrea; Soltau, Heike; Stefanescu, Alexander; Tenzer, Chris; Treis, Johannes; Tsunemi, Hiroshi; de Vita, Giulio; Wilms, Jörn

    2010-07-01

    The Wide Field Imager (WFI) of the International X-ray Observatory (IXO) is an X-ray imaging spectrometer based on a large monolithic DePFET (Depleted P-channel Field Effect Transistor) Active Pixel Sensor. Filling an area of 10 x 10 cm2 with a format of 1024 x 1024 pixels it will cover a field of view of 18 arcmin. The pixel size of 100 x 100 μm2 corresponds to a fivefold oversampling of the telescope's expected 5 arcsec point spread function. The WFI's basic DePFET structure combines the functionalities of sensor and integrated amplifier with nearly Fano-limited energy resolution and high efficiency from 100 eV to 15 keV. The development of dedicated control and amplifier ASICs allows for high frame rates up to 1 kHz and flexible readout modes. Results obtained with representative prototypes with a format of 256 x 256 pixels are presented.

  19. Optical And Near-infrared Variability Among Distant Galactic Nuclei Of The CANDELS/Wide Fields

    NASA Astrophysics Data System (ADS)

    Grogin, Norman A.; Conselice, Christopher J.; Donley, Jennifer; Kartaltepe, Jeyhan; Kocevski, Dale; Koekemoer, Anton M.; Lucas, Ray; McGrath, Elizabeth; Rajan, Abhijit; Rosario, David; Salvato, Mara; Villforth, Carolin

    2015-08-01

    Three of the five fields surveyed during 2010-2013 by the CANDELS HST Multi-cycle Treasury Program were so-called "Wide" fields: CANDELS/UDS; CANDELS/COSMOS; and CANDELS/EGS. The area covered by CANDELS/Wide comprises WFC3/IR exposures in J-band and H-band across a total of 585 square arcminutes, and coordinated parallel ACS/WFC exposures in V-band and I-band across a total of 750 square arcminutes that largely overlaps the WFC3/IR coverage. In each field, these observations were split between two epochs with 52-day spacing for the primary purpose of high-redshift SNe detection and follow-up. However, the CANDELS combination of sensitivity, high resolution, and time spacing is also well-suited to detect optical and near-infrared variability ("ONIV") among moderate- to high-redshift galaxy nuclei (H<25AB mag; I<26AB mag).These data are sensitive to rest-frame variability time-scales of up to several weeks, and prior ACS/WFC imaging in CANDELS/COSMOS and CANDELS/EGS extends variability sensitivity to several years in the V- and I-bands. The overwhelming majority of these variable galaxy nuclei will be AGN; the small fraction arising from SNe have already been meticulously culled by the CANDELS high-redshift SNe search effort. These ONIV galaxy nuclei potentially represent a significant addition to the census of distant lower-luminosity AGN subject to multi-wavelength scrutiny with CANDELS.We present the combined results of our variability analyses, leading to the discovery of 133 I-band and 132 H-band ONIVs in CANDELS/Wide. We compare these HST-detected ONIVs with the known AGN candidates in the fields from deep Spitzer and Chandra imaging, and from extensive ground-based optical spectroscopy as well as HST IR-grism spectroscopy. We also assess the redshift distribution of the ONIVs from both spectroscopy and from robust SED-fitting incorporating ancillary deep ground-based imaging along with the CANDELS VIJH photometry. The I-band and H-band ONIVs are largely non

  20. Searching for fast optical transients by means of a wide-field monitoring observations with high temporal resolution

    NASA Astrophysics Data System (ADS)

    Beskin, G.; Karpov, S.; Plokhotnichenko, V.; Bondar, S.; Ivanov, E.; Perkov, A.; Greco, G.; Guarnieri, A.; Bartolini, C.

    We discuss the strategy of search for fast optical transients accompanying gamma-ray bursts by means of continuous monitoring of wide sky fields with high temporal resolution. We describe the design, performance and results of our cameras, FAVOR and TORTORA. Also we discuss the perspectives of this strategy and possible design of next-generation equipment for wide-field monitoring which will be able to detect optical transients and to study their color and polarization properties with high time resolution.

  21. Wide-field retinal optical coherence tomography with wavefront sensorless adaptive optics for enhanced imaging of targeted regions

    PubMed Central

    Polans, James; Keller, Brenton; Carrasco-Zevallos, Oscar M.; LaRocca, Francesco; Cole, Elijah; Whitson, Heather E.; Lad, Eleonora M.; Farsiu, Sina; Izatt, Joseph A.

    2016-01-01

    The peripheral retina of the human eye offers a unique opportunity for assessment and monitoring of ocular diseases. We have developed a novel wide-field (>70°) optical coherence tomography system (WF-OCT) equipped with wavefront sensorless adaptive optics (WSAO) for enhancing the visualization of smaller (<25°) targeted regions in the peripheral retina. We iterated the WSAO algorithm at the speed of individual OCT B-scans (~20 ms) by using raw spectral interferograms to calculate the optimization metric. Our WSAO approach with a 3 mm beam diameter permitted primarily low- but also high- order peripheral wavefront correction in less than 10 seconds. In preliminary imaging studies in five normal human subjects, we quantified statistically significant changes with WSAO correction, corresponding to a 10.4% improvement in average pixel brightness (signal) and 7.0% improvement in high frequency content (resolution) when visualizing 1 mm (~3.5°) B-scans of the peripheral (>23°) retina. We demonstrated the ability of our WF-OCT system to acquire non wavefront-corrected wide-field images rapidly, which could then be used to locate regions of interest, zoom into targeted features, and visualize the same region at different time points. A pilot clinical study was conducted on seven healthy volunteers and two subjects with prodromal Alzheimer’s disease which illustrated the capability to image Drusen-like pathologies as far as 32.5° from the fovea in un-averaged volume scans. This work suggests that the proposed combination of WF-OCT and WSAO may find applications in the diagnosis and treatment of ocular, and potentially neurodegenerative, diseases of the peripheral retina, including diabetes and Alzheimer’s disease. PMID:28101398

  22. Wide-field retinal optical coherence tomography with wavefront sensorless adaptive optics for enhanced imaging of targeted regions.

    PubMed

    Polans, James; Keller, Brenton; Carrasco-Zevallos, Oscar M; LaRocca, Francesco; Cole, Elijah; Whitson, Heather E; Lad, Eleonora M; Farsiu, Sina; Izatt, Joseph A

    2017-01-01

    The peripheral retina of the human eye offers a unique opportunity for assessment and monitoring of ocular diseases. We have developed a novel wide-field (>70°) optical coherence tomography system (WF-OCT) equipped with wavefront sensorless adaptive optics (WSAO) for enhancing the visualization of smaller (<25°) targeted regions in the peripheral retina. We iterated the WSAO algorithm at the speed of individual OCT B-scans (~20 ms) by using raw spectral interferograms to calculate the optimization metric. Our WSAO approach with a 3 mm beam diameter permitted primarily low- but also high- order peripheral wavefront correction in less than 10 seconds. In preliminary imaging studies in five normal human subjects, we quantified statistically significant changes with WSAO correction, corresponding to a 10.4% improvement in average pixel brightness (signal) and 7.0% improvement in high frequency content (resolution) when visualizing 1 mm (~3.5°) B-scans of the peripheral (>23°) retina. We demonstrated the ability of our WF-OCT system to acquire non wavefront-corrected wide-field images rapidly, which could then be used to locate regions of interest, zoom into targeted features, and visualize the same region at different time points. A pilot clinical study was conducted on seven healthy volunteers and two subjects with prodromal Alzheimer's disease which illustrated the capability to image Drusen-like pathologies as far as 32.5° from the fovea in un-averaged volume scans. This work suggests that the proposed combination of WF-OCT and WSAO may find applications in the diagnosis and treatment of ocular, and potentially neurodegenerative, diseases of the peripheral retina, including diabetes and Alzheimer's disease.

  23. Development of a Reduction Algorithm of GEO Satellite Optical Observation Data for Optical Wide Field Patrol (OWL)

    NASA Astrophysics Data System (ADS)

    Park, Sun-youp; Choi, Jin; Jo, Jung Hyun; Son, Ju Young; Park, Yung-Sik; Yim, Hong-Suh; Moon, Hong-Kyu; Bae, Young-Ho; Choi, Young-Jun; Park, Jang-Hyun

    2015-09-01

    An algorithm to automatically extract coordinate and time information from optical observation data of geostationary orbit satellites (GEO satellites) or geosynchronous orbit satellites (GOS satellites) is developed. The optical wide-field patrol system is capable of automatic observation using a pre-arranged schedule. Therefore, if this type of automatic analysis algorithm is available, daily unmanned monitoring of GEO satellites can be possible. For data acquisition for development, the COMS1 satellite was observed with 1-s exposure time and 1-m interval. The images were grouped and processed in terms of ¡°action¡±, and each action was composed of six or nine successive images. First, a reference image with the best quality in one action was selected. Next, the rest of the images in the action were geometrically transformed to fit in the horizontal coordinate system (expressed in azimuthal angle and elevation) of the reference image. Then, these images were median-combined to retain only the possible non-moving GEO candidates. By reverting the coordinate transformation of the positions of these GEO satellite candidates, the final coordinates could be calculated.

  24. All-weather calibration of wide-field optical and NIR surveys

    SciTech Connect

    Burke, David L.; Saha, Abhijit; Claver, Jenna; Claver, Chuck; Axelrod, T.; DePoy, Darren; Ivezić, Željko; Jones, Lynne; Smith, R. Chris; Stubbs, Christopher W.

    2014-01-01

    The science goals for ground-based large-area surveys, such as the Dark Energy Survey, Pan-STARRS, and the Large Synoptic Survey Telescope, require calibration of broadband photometry that is stable in time and uniform over the sky to precisions of a percent or better. This performance will need to be achieved with data taken over the course of many years, and often in less than ideal conditions. This paper describes a strategy to achieve precise internal calibration of imaging survey data taken in less than 'photometric' conditions, and reports results of an observational study of the techniques needed to implement this strategy. We find that images of celestial fields used in this case study with stellar densities ∼1 arcmin{sup –2} and taken through cloudless skies can be calibrated with relative precision ∼0.5% (reproducibility). We report measurements of spatial structure functions of cloud absorption observed over a range of atmospheric conditions, and find it possible to achieve photometric measurements that are reproducible to 1% in images that were taken through cloud layers that transmit as little as 25% of the incident optical flux (1.5 magnitudes of extinction). We find, however, that photometric precision below 1% is impeded by the thinnest detectable cloud layers. We comment on implications of these results for the observing strategies of future surveys.

  1. Optical Design Trade Study for the Wide Field Infrared Survey Telescope [WFIRST

    NASA Technical Reports Server (NTRS)

    Content, David A.; Goullioud, R.; Lehan, John P.; Mentzell, John E.

    2011-01-01

    The Wide Field Infrared Survey Telescope (WFIRST) mission concept was ranked first in new space astrophysics mission by the Astro2010 Decadal Survey incorporating the Joint Dark Energy Mission (JDEM)-Omega payload concept and multiple science white papers. This mission is based on a space telescope at L2 studying exoplanets [via gravitational microlensing], probing dark energy, and surveying the near infrared sky. Since the release of NWNH, the WFIRST project has been working with the WFIRST science definition team (SDT) to refine mission and payload concepts. We present the driving requirements. The current interim reference mission point design, based on the use of a 1.3m unobscured aperture three mirror anastigmat form, with focal imaging and slitless spectroscopy science channels, is consistent with the requirements, requires no technology development, and out performs the JDEM-Omega design.

  2. Foveated Wide Field-of-View Imaging for Missile Warning/Tracking using Adaptive Optics

    DTIC Science & Technology

    2007-11-30

    Topical Meeting On Optics of Liquid Crystals, OLC 2007, Puebla , Mexico (October 2007) 13. A. Parish, S. Gauza, S.T. Wu, J. Dziaduszek, and R. Dabrowski...New fluorinated terphenyl isothiocyanate liquid crystals” 12th International Topical Meeting On Optics of Liquid Crystals, OLC 2007, Puebla , Mexico

  3. Field-balanced adaptive optics error function for wide field-of-view space-based systems

    NASA Astrophysics Data System (ADS)

    McComas, Brian K.; Friedman, Edward J.

    2002-03-01

    Adaptive optics are regularly used in ground-based astronomical telescopes. These applications are characterized by a very narrow (approximately 1 arcmin) field of view. For economic reasons, commercial space-based earth-observing optical systems must have a field of view as large as possible. We develop a new error function that is an extension of conventional adaptive optics for wide field-of-view optical systems and show that this new error function enables diffraction-limited performance across a large field of view with only one deformable mirror. This new error function allows for reprogramming of aberration control algorithms for particular applications by the use of an addressable weighting function.

  4. Development of a lightweight near-zero CTE optical bench for the Wide-Field Camera 3 instrument

    NASA Astrophysics Data System (ADS)

    Holz, Jill M.; Kunt, Cengiz; Lashley, Chris; McGuffey, Douglas B.

    2003-02-01

    The design and development of an optical bench (OB) for Wide Field Camera 3 (WFC3), a next generation science instrument for the Hubble Space Telescope (HST) has proven a challenging task. WFC3 will replace Wide Field Planetary Camera 2 (WF/PC 2) during the next servicing mission of the HST in 2004. The WFC3 program is re-using much of the hardware from WF/PC 1, returned from the First Servicing Mission, which has added complexity to the program. This posed some significant packaging challenges, further complicated by WFC3 utilizing two, separate optical channels. The WF/PC 1 optical bench could not house the additional optical components, so a new bench was developed. The new bench had to be designed to accommodate the sometimes-conflicting requirements of the two channels, which operate over a wavelength range of 200nm to 1800nm, from Near Ultraviolet to Near Infrared. In addition, the bench had to interface to the reused WF/PC 1 hardware, which was not optimized for this mission. To aid in the design of the bench, the team used software tools to merge structural, thermal and optical models to obtain performance (STOP) of the optical systems in operation. Several iterations of this performance analysis were needed during the design process to verify the bench would meet requirements. The fabrication effort included a rigorous material characterization program and significant tooling. After assembly, the optical bench underwent an extensive qualification program to prove the design and manufacturing processes. This paper provides the details of the design and development process of this highly optimized optical bench.

  5. All sky coordination initiative, simple service for wide-field monitoring systems to cooperate in searching for fast optical transients

    NASA Astrophysics Data System (ADS)

    Karpov, S.; Sokołowski, M.; Gorbovskoy, E.

    Here we stress the necessity of cooperation between different wide-field monitoring projects (FAVOR/TORTORA, Pi of the Sky, MASTER, etc), aimed for independent detection of fast optical transients, in order to maximize the area of the sky covered at any moment and to coordinate the monitoring of gamma-ray telescopes' field of view. We review current solutions available for it and propose a simple protocol with dedicated service (ASCI) for such systems to share their current status and pointing schedules.

  6. Removing static aberrations from the active optics system of a wide-field telescope.

    PubMed

    Schipani, Pietro; Noethe, Lothar; Arcidiacono, Carmelo; Argomedo, Javier; Dall'Ora, Massimo; D'Orsi, Sergio; Farinato, Jacopo; Magrin, Demetrio; Marty, Laurent; Ragazzoni, Roberto; Umbriaco, Gabriele

    2012-07-01

    The wavefront sensor in active and adaptive telescopes is usually not in the optical path toward the scientific detector. It may generate additional wavefront aberrations, which have to be separated from the errors due to the telescope optics. The aberrations that are not rotationally symmetric can be disentangled from the telescope aberrations by a series of measurements taken in the center of the field, with the wavefront sensor at different orientation angles with respect to the focal plane. This method has been applied at the VLT Survey Telescope on the ESO Paranal observatory.

  7. Alternate optical designs for head-mounted displays with a wide field of view.

    PubMed

    Chen, Bo; Herkommer, Alois M

    2017-02-01

    The most widely applied design form for mixed reality head-mounted display (HMD) systems is generally a prism with one surface in total internal reflection (TIR). This, however, limits the angle of the incident rays, and thus decreases the design freedom and affects the performance. To obtain better performance of the HMD optics, in this paper two seldom used design forms of HMD systems are presented and compared to the standard TIR HMD optics. One of them is a catadioptric HMD system, consisting of one lens and two mirrors; the other is a prism HMD with a different folding geometry. The designs are compared for a field of view of 40°×30°; however, they are also investigated for an increased field of view of 50°×30°. The evaluation indicates good performance of our systems. In particular, the prism with an alternate folding geometry has advantages in both performance and size.

  8. Design of refractive fore-optics with wide field of view and waveband for miniature imaging spectrometer

    NASA Astrophysics Data System (ADS)

    Mao, Jingchao; Xu, Minyi; Liu, Qinghan; Shen, Weimin

    2016-10-01

    With the development of unmanned airborne vehicle (UAV) remote sensing technology, miniature high-resolution imaging spectrometers are greatly needed. In order to improve remote sensing efficiency and get wider coverage, it's urgent to design and develop fore-optics with wide field of view and waveband for imaging spectrometer. As the refractive system has no central obscuration and it's conducive to manufacture and assemble, so it's used for our fore-optics. The key is the correction of secondary spectrum of systems working in broad waveband and meeting the requirement of imagery telecentricity to be appropriate for linear pushbroom imaging system. Suitable glasses are selected on the Glass Map, from where each glass has an Abbe number υd and Partial Dispersion. Based on the theory of Gaussian Optics and Seidel third-order aberration theory, the paper derives apochromatic formula, and the power of individual lenses can be calculated. Then with a required value of spherical aberration and coma, this paper derives equations to calculate the initial structure of apochromatic optical systems. Finally, optimized refractive SWIR fore-optics working in 1μm-2.5μm with effective focal length (EFFL) of 11mm is reported. Its full field and F-number are respectively 40°, F/2.8. The system has many advantages such as simple and compact structure, small size, near diffraction-limited imaging quality, small secondary spectrum and imagery telecentricity. Especially it consists of spherical surfaces that can greatly reduce the difficulty and the cost of manufacture as well as test, which is applicable for SWIR imaging spectrometer with wide field of view.

  9. The explosive transient camera - An automatic, wide-field sky monitor for short-timescale optical transients

    NASA Technical Reports Server (NTRS)

    Vanderspek, Roland K.; Ricker, George R.; Doty, John P.

    1992-01-01

    The Explosive Transient Camera (ETC) is a widefield sky monitor designed to detect short-timescale (1-l0 s) celestial optical flashes. It consists of two arrays of wide-field CCD cameras monitoring about 0.4 steradian of the night sky for optical transients with risetimes of about 1-10 s and peak magnitudes m(V) of less than about 10. The ETC was designed to be completely automated in order to make year-round observations with minimal human intervention. A small, powerful 68,000-based computer controls all aspects of observations, including roof motion, CCD readouts, and weather sensing: under software control, the ETC is able to perform all the functions of a human observer automatically.

  10. KMTNET: A Network of 1.6 m Wide-Field Optical Telescopes Installed at Three Southern Observatories

    NASA Astrophysics Data System (ADS)

    Kim, Seung-Lee; Lee, Chung-Uk; Park, Byeong-Gon; Kim, Dong-Jin; Cha, Sang-Mok; Lee, Yongseok; Han, Cheongho; Chun, Moo-Young; Yuk, Insoo

    2016-02-01

    The Korea Microlensing Telescope Network (KMTNet) is a wide-field photometric system installed by the Korea Astronomy and Space Science Institute (KASI). Here, we present the overall technical specifications of the KMTNet observation system, test observation results, data transfer and image processing procedure, and finally, the KMTNet science programs. The system consists of three 1.6 m wide-field optical telescopes equipped with mosaic CCD cameras of 18k by 18k pixels. Each telescope provides a 2.0 by 2.0 square degree field of view. We have finished installing all three telescopes and cameras sequentially at the Cerro-Tololo Inter-American Observatory (CTIO) in Chile, the South African Astronomical Observatory (SAAO) in South Africa, and the Siding Spring Observatory (SSO) in Australia. This network of telescopes, which is spread over three different continents at a similar latitude of about -30 degrees, enables 24-hour continuous monitoring of targets observable in the Southern Hemisphere. The test observations showed good image quality that meets the seeing requirement of less than 1.0 arcsec in I-band. All of the observation data are transferred to the KMTNet data center at KASI via the international network communication and are processed with the KMTNet data pipeline. The primary scientific goal of the KMTNet is to discover numerous extrasolar planets toward the Galactic bulge by using the gravitational microlensing technique, especially earth-mass planets in the habitable zone. During the non-bulge season, the system is used for wide-field photometric survey science on supernovae, asteroids, and external galaxies.

  11. A future wide field-of-view TeV gamma-ray observatory in the Southern Hemisphere

    NASA Astrophysics Data System (ADS)

    Mostafa, Miguel; HAWC Collaboration

    2017-01-01

    High-energy gamma-ray observations are an essential probe of cosmic-ray acceleration. Detection of the highest energies and the shortest timescales of variability are key motivations when designing the next generation of gamma-ray experiments. The Milagro experiment was the first-generation of gamma-ray detectors based on the water-Cherenkov technique, and demonstrated that it is possible to continuously monitor a large fraction of the TeV sky. The second-generation water-Cherenkov experiment, the High Altitude Water Cherenkov observatory, consists of an array of 300 water-Cherenkov detectors covering an area of 22,000 m2 at 4,100 m a.s.l. The larger effective area, the higher altitude, and the optical isolation of the detectors led to a 15-fold increase in sensitivity relative to Milagro. Instruments with a wide field of view and large duty cycle are capable of surveying the TeV sky, mapping the diffuse emission, detecting emission from extended regions, and observing transient events such as gamma ray bursts. They also have the potential for discovering electromagnetic counterparts to gravitational waves and astrophysical neutrinos. I will present the preliminary design of a third-generation water-Cherenkov observatory located at very high altitude in South America.

  12. Improvements in Space Surveillance Processing for Wide Field of View Optical Sensors

    NASA Astrophysics Data System (ADS)

    Sydney, P.; Wetterer, C.

    2014-09-01

    For more than a decade, an autonomous satellite tracking system at the Air Force Maui Optical and Supercomputing (AMOS) observatory has been generating routine astrometric measurements of Earth-orbiting Resident Space Objects (RSOs) using small commercial telescopes and sensors. Recent work has focused on developing an improved processing system, enhancing measurement performance and response while supporting other sensor systems and missions. This paper will outline improved techniques in scheduling, detection, astrometric and photometric measurements, and catalog maintenance. The processing system now integrates with Special Perturbation (SP) based astrodynamics algorithms, allowing covariance-based scheduling and more precise orbital estimates and object identification. A merit-based scheduling algorithm provides a global optimization framework to support diverse collection tasks and missions. The detection algorithms support a range of target tracking and camera acquisition rates. New comprehensive star catalogs allow for more precise astrometric and photometric calibrations including differential photometry for monitoring environmental changes. This paper will also examine measurement performance with varying tracking rates and acquisition parameters.

  13. FRD in optical fibres at low temperatures: investigations for Gemini's Wide-field Fibre Multi-Object Spectrograph

    NASA Astrophysics Data System (ADS)

    de Oliveira, A. C.; de Oliveira, L. S.; Dos Santos, J. B.; Arruda, M. V.; Dos Santos, L. G. C.; Rodrigues, F.; de Castro, F. L. F.

    2011-06-01

    While there is no direct evidence for the deterioration in Focal Ratio Degradation (FRD) of optical fibres in severe temperature gradients, the fibre ends inserted into metallic containment devices such as steel ferrules can be a source of stress, and hence increased FRD at low temperatures. In such conditions, instruments using optical fibres may suffer some increase in FRD and consequent loss of system throughput when they are working in environments with significant thermal gradients, a common characteristic of ground-based observatories. In this paper we present results of experiments with optical fibres inserted in different materials as a part of our prototyping study for Gemini's Wide-field Multi-Object Spectrograph (WFMOS) project. Thermal effects and the use of new holding techniques will be discussed in the context of Integral Field Units and multi-fibres systems. In this work, we have used careful methodologies that give absolute measurements of FRD to quantify the advantages of using epoxy-based composites rather than metals as support structures for the fibre ends. This is shown to be especially important in minimizing thermally induced stresses in the fibre terminations. Not only is this important for optimizing fibre spectrograph performance but the benefits of using such materials are demonstrated in the minimization of positional variations and the avoidance of metal-to-glass delamination. Furthermore, by impregnating the composites with small zirconium oxide particles the composite materials supply their own fine polishing grit which aids significantly to the optical quality of the finished product.

  14. Automated three-dimensional registration and volume rebuilding for wide-field angiographic and structural optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Zang, Pengxiao; Liu, Gangjun; Zhang, Miao; Wang, Jie; Hwang, Thomas S.; Wilson, David J.; Huang, David; Li, Dengwang; Jia, Yali

    2017-02-01

    We propose a three-dimensional (3-D) registration method to correct motion artifacts and construct the volume structure for angiographic and structural optical coherence tomography (OCT). This algorithm is particularly suitable for the nonorthogonal wide-field OCT scan acquired by a ultrahigh-speed swept-source system (>200 kHz A-scan rate). First, the transverse motion artifacts are corrected by the between-frame registration based on en face OCT angiography (OCTA). After A-scan transverse translation between B-frames, the axial motions are corrected based on the rebuilt boundary of inner limiting membrane. Finally, a within-frame registration is performed for local optimization based on cross-sectional OCTA. We evaluated this algorithm on retinal volumes of six normal subjects. The results showed significantly improved retinal smoothness in 3-D-registered structural OCT and image contrast on en face OCTA.

  15. Update on BOMBOLO: a 3-arm, wide-field, near-UV/optical imager for the 4-meter SOAR telescope

    NASA Astrophysics Data System (ADS)

    Garcés, Eduardo; Guzmán, Dani; Jones, Damien; Angeloni, Rodolfo; Puzia, Thomas

    2016-08-01

    BOMBOLO is our instrument proposal for covering a series of scientific cases, in the not-so-explored time window of tens of seconds to minutes exposures, to be installed at the SOAR observatory. BOMBOLO is a wide field imager, capable of simultaneous, synchronous and independent observations in three different bands of the near-UV and visible wavelengths. BOMBOLO will be located at one of the Bent Cassegrain focal stations. Given its length, weight and mounting limitations, we discuss the current mechanical and opto-mechanical design of the instrument, given flexures caused by a changing gravity vector. In order to validate our designs, a Monte-Carlo simulation is used to explore different observing conditions, as the starting point for static and dynamic studies of the structure using Finite Element Analysis tools. A quick update on the current state of the instrument related to the optical design and manufacturing as well as the CCD cameras is included.

  16. Active optics and modified-Rumsey wide-field telescopes: MINITRUST demonstrators with vase- and tulip-form mirrors

    NASA Astrophysics Data System (ADS)

    Lemaître, Gérard R.; Montiel, Pierre; Joulié, Patrice; Dohlen, Kjetil; Lanzoni, Patrick

    2005-12-01

    Wide-field astronomy requires the development of larger aperture telescopes. The optical properties of a three-mirror modified-Rumsey design provide significant advantages when compared to other telescope designs: (i) at any wavelength, the design has a flat field and is anastigmatic; (ii) the system is extremely compact, i.e., it is almost four times shorter than a Schmidt. Compared to the equally compact flat-field Ritchey-Chrétien with a doublet-lens corrector, as developed for the Sloan digital sky survey - and which requires the polishing of six optical surfaces - the proposed modified-Rumsey design requires only a two-surface polishing and provides a better imaging quality. All the mirrors are spheroids of the hyperboloid type. Starting from the classical Rumsey design, it is shown that the use of all eight available free parameters allows the simultaneous aspherization of the primary and tertiary mirrors by active optics methods from a single deformable substrate. The continuity conditions between the primary and the tertiary hyperbolizations are achieved by an intermediate narrow ring of constant thickness that is not optically used. After the polishing of a double vase form in a spherical shape, the primary-tertiary hyperbolizations are achieved by in situ stressing. The tulip-form secondary is hyperbolized by stress polishing. Other active optics alternatives are possible for a space telescope. The modified-Rumsey design is of interest for developing large space- and ground-based survey telescopes in UV, visible, or IR ranges, such as currently demonstrated with the construction of identical telescopes MINITRUST-1 and -2, f/5 - 2° field of view. Double-pass optical tests show diffraction-limited images.

  17. Active optics and modified-Rumsey wide-field telescopes: MINITRUST demonstrators with vase- and tulip-form mirrors.

    PubMed

    Lemaître, Gérard R; Montiel, Pierre; Joulié, Patrice; Dohlen, Kjetil; Lanzoni, Patrick

    2005-12-01

    Wide-field astronomy requires the development of larger aperture telescopes. The optical properties of a three-mirror modified-Rumsey design provide significant advantages when compared to other telescope designs: (i) at any wavelength, the design has a flat field and is anastigmatic; (ii) the system is extremely compact, i.e., it is almost four times shorter than a Schmidt. Compared to the equally compact flat-field Ritchey-Chrétien with a doublet-lens corrector, as developed for the Sloan digital sky survey-and which requires the polishing of six optical surfaces-the proposed modified-Rumsey design requires only a two-surface polishing and provides a better imaging quality. All the mirrors are spheroids of the hyperboloid type. Starting from the classical Rumsey design, it is shown that the use of all eight available free parameters allows the simultaneous aspherization of the primary and tertiary mirrors by active optics methods from a single deformable substrate. The continuity conditions between the primary and the tertiary hyperbolizations are achieved by an intermediate narrow ring of constant thickness that is not optically used. After the polishing of a double vase form in a spherical shape, the primary-tertiary hyperbolizations are achieved by in situ stressing. The tulip-form secondary is hyperbolized by stress polishing. Other active optics alternatives are possible for a space telescope. The modified-Rumsey design is of interest for developing large space- and ground-based survey telescopes in UV, visible, or IR ranges, such as currently demonstrated with the construction of identical telescopes MINITRUST-1 and -2, f/5-2 degrees field of view. Double-pass optical tests show diffraction-limited images.

  18. Andromeda (M31) optical and infrared disk survey. I. Insights in wide-field near-IR surface photometry

    SciTech Connect

    Sick, Jonathan; Courteau, Stéphane; Cuillandre, Jean-Charles; McDonald, Michael; De Jong, Roelof; Tully, R. Brent

    2014-05-01

    We present wide-field near-infrared J and K{sub s} images of the Andromeda Galaxy (M31) taken with WIRCam at the Canada-France-Hawaii Telescope as part of the Andromeda Optical and Infrared Disk Survey. This data set allows simultaneous observations of resolved stars and near-infrared (NIR) surface brightness across M31's entire bulge and disk (within R = 22 kpc), permitting a direct test of the stellar composition of near-infrared light in a nearby galaxy. Here we develop NIR observation and reduction methods to recover a uniform surface brightness map across the 3° × 1° disk of M31 with 27 WIRCam fields. Two sky-target nodding strategies are tested, and we find that strictly minimizing sky sampling latency cannot improve background subtraction accuracy to better than 2% of the background level due to spatio-temporal variations in the NIR skyglow. We fully describe our WIRCam reduction pipeline and advocate using flats built from night-sky images over a single night, rather than dome flats that do not capture the WIRCam illumination field. Contamination from scattered light and thermal background in sky flats has a negligible effect on the surface brightness shape compared to the stochastic differences in background shape between sky and galaxy disk fields, which are ∼0.3% of the background level. The most dramatic calibration step is the introduction of scalar sky offsets to each image that optimizes surface brightness continuity. Sky offsets reduce the mean surface brightness difference between observation blocks from 1% to <0.1% of the background level, though the absolute background level remains statistically uncertain to 0.15% of the background level. We present our WIRCam reduction pipeline and performance analysis to give specific recommendations for the improvement of NIR wide-field imaging methods.

  19. 3D galaxy clustering with future wide-field surveys: Advantages of a spherical Fourier-Bessel analysis

    NASA Astrophysics Data System (ADS)

    Lanusse, F.; Rassat, A.; Starck, J.-L.

    2015-06-01

    figure of merit as a function of median redshift is higher for the 3D SFB method than for the 2D tomographic method. Conclusions: Constraints from the 3D SFB analysis are less sensitive to unavoidable systematics stemming from a redshift- and scale-dependent galaxy bias. Even for surveys that are optimised with tomography in mind, a 3D SFB analysis is more powerful. In addition, for survey optimisation, the figure of merit for the 3D SFB method increases more rapidly with redshift, especially at higher redshifts, suggesting that the 3D SFB method should be preferred for designing and analysing future wide-field spectroscopic surveys. CosmicPy, the Python package developed for this paper, is freely available at https://cosmicpy.github.io. Appendices are available in electronic form at http://www.aanda.org

  20. Wide-field imaging of retinal vasculature using optical coherence tomography-based microangiography provided by motion tracking

    PubMed Central

    Zhang, Qinqin; Huang, Yanping; Zhang, Thomas; Kubach, Sophie; An, Lin; Laron, Michal; Sharma, Utkarsh; Wang, Ruikang K.

    2015-01-01

    Abstract. Optical coherence tomography (OCT)-based optical microangiography (OMAG) is a high-resolution, noninvasive imaging technique capable of providing three-dimensional in vivo blood flow visualization within microcirculatory tissue beds in the eye. Although the technique has demonstrated early clinical utility by imaging diseased eyes, its limited field of view (FOV) and the sensitivity to eye motion remain the two biggest challenges for the widespread clinical use of the technology. Here, we report the results of retinal OMAG imaging obtained from a Zeiss Cirrus 5000 spectral domain OCT system with motion tracking capability achieved by a line scan ophthalmoscope (LSO). The tracking LSO is able to guide the OCT scanning, which minimizes the effect of eye motion in the final results. We show that the tracking can effectively correct the motion artifacts and remove the discontinuities and distortions of vascular appearance due to microsaccade, leading to almost motion-free OMAG angiograms with good repeatability and reliability. Due to the robustness of the tracking LSO, we also show the montage scan protocol to provide unprecedented wide field retinal OMAG angiograms. We experimentally demonstrate a 12×16  mm2 retinal OMAG angiogram acquired from a volunteer, which is the widest FOV retinal vasculature imaging up to now in the community. PMID:26102573

  1. Wide-field optical monitoring with Mini-MegaTORTORA (MMT-9) multichannel high temporal resolution telescope

    NASA Astrophysics Data System (ADS)

    Beskin, G. M.; Karpov, S. V.; Biryukov, A. V.; Bondar, S. F.; Ivanov, E. A.; Katkova, E. V.; Orekhova, N. V.; Perkov, A. V.; Sasyuk, V. V.

    2017-01-01

    We describe the properties of Mini-MegaTORTORA (MMT-9) nine-channel wide-field optical sky monitoring system with subsecond temporal resolution. This instrument can observe sky areas as large as 900 deg2, perform photometry in three filters close to Johnson BV R system and polarimetry of selected objects or areas with 100-300 deg2 sizes. The limiting magnitude of the system is up to V = 11m for 0.1 s temporal resolution, and reaches V = 15m in minute-long exposures. The system is equipped with a powerful computing facility and dedicated software pipeline allowing it to perform automatic detection, real-time classification, and investigation of transient events of different nature located both in the near- Earth space and at extragalactic distances. The objects routinely detected by MMT-9 include faint meteors and artificial Earth satellites.We discuss astronomical tasks that can be solved using MMT-9, and present the results of the first two years of its operation. In particular, we report the parameters of the optical flare detected on June 25, 2016, which accompanied the gamma-ray burst GRB160625B.

  2. Instrumentation of LOTIS: Livermore Optical Transient Imaging System; a fully automated wide field of view telescope system searching for simultaneous optical counterparts of gamma ray bursts

    SciTech Connect

    Park, H.S.; Ables, E.; Barthelmy, S.D.; Bionta, R.M.; Ott, L.L.; Parker, E.L.; Williams, G.G.

    1998-03-06

    LOTIS is a rapidly slewing wide-field-of-view telescope which was designed and constructed to search for simultaneous gamma-ray burst (GRB) optical counterparts. This experiment requires a rapidly slewing ({lt} 10 sec), wide-field-of-view ({gt} 15{degrees}), automatic and dedicated telescope. LOTIS utilizes commercial tele-photo lenses and custom 2048 x 2048 CCD cameras to view a 17.6 x 17.6{degrees} field of view. It can point to any part of the sky within 5 sec and is fully automated. It is connected via Internet socket to the GRB coordinate distribution network which analyzes telemetry from the satellite and delivers GRB coordinate information in real-time. LOTIS started routine operation in Oct. 1996. In the idle time between GRB triggers, LOTIS systematically surveys the entire available sky every night for new optical transients. This paper will describe the system design and performance.

  3. Tiling strategies for optical follow-up of gravitational-wave triggers by telescopes with a wide field of view

    NASA Astrophysics Data System (ADS)

    Ghosh, Shaon; Bloemen, Steven; Nelemans, Gijs; Groot, Paul J.; Price, Larry R.

    2016-08-01

    Aims: Binary neutron stars are among the most promising candidates for joint gravitational-wave and electromagnetic astronomy. The goal of this work is to investigate various observing strategies that telescopes with wide field of view might incorporate while searching for electromagnetic counterparts of gravitational-wave triggers. Methods: We examined various strategies of scanning the gravitational-wave sky localizations on the mock 2015-16 gravitational-wave events. First, we studied the performance of the sky coverage using a naive tiling system that completely covers a given confidence interval contour using a fixed grid. Then we propose the ranked-tiling strategy where we sample the localization in discrete two-dimensional intervals that are equivalent to the telescope's field of view and rank them based on their sample localizations. We then introduce an optimization of the grid by iterative sliding of the tiles. Next, we conducted tests for all the methods on a large sample of sky localizations that are expected in the first two years of operation of the Laser interferometer Gravitational-wave Observatory (LIGO) and Virgo detectors. We investigated the performance of the ranked-tiling strategy for telescope arrays and compared their performance against monolithic telescopes with a giant field of view. Finally, we studied the ability of optical counterpart detection by various types of telescopes. Results: Our analysis reveals that the ranked-tiling strategy improves the localization coverage over the contour-covering method. The improvement is more significant for telescopes with larger fields of view. We also find that while optimizing the position of the tiles significantly improves the coverage compared to contour-covering tiles. For ranked-tiles the same procedure leads to negligible improvement in the coverage of the sky localizations. We observed that distributing the field of view of the telescopes into arrays of multiple telescopes significantly

  4. BOMBOLO: a Multi-Band, Wide-field, Near UV/Optical Imager for the SOAR 4m Telescope

    NASA Astrophysics Data System (ADS)

    Angeloni, R.; Guzmán, D.; Puzia, T. H.; Infante, L.

    2014-10-01

    BOMBOLO is a new multi-passband visitor instrument for SOAR observatory. The first fully Chilean instrument of its kind, it is a three-arms imager covering the near-UV and optical wavelengths. The three arms work simultaneously and independently, providing synchronized imaging capability for rapid astronomical events. BOMBOLO will be able to address largely unexplored events in the minute-to-second timescales, with the following leading science cases: 1) Simultaneous Multiband Flickering Studies of Accretion Phenomena; 2) Near UV/Optical Diagnostics of Stellar Evolutionary Phases; 3) Exoplanetary Transits and 4) Microlensing Follow-Up. BOMBOLO optical design consists of a wide field collimator feeding two dychroics at 390 and 550 nm. Each arm encompasses a camera, filter wheel and a science CCD230-42, imaging a 7 x 7 arcmin field of view onto a 2k x 2k image. The three CCDs will have different coatings to optimise the efficiencies of each camera. The detector controller to run the three cameras will be Torrent (the NOAO open-source system) and a PanView application will run the instrument and produce the data-cubes. The instrument is at Conceptual Design stage, having been approved by the SOAR Board of Directors as a visitor instrument in 2012 and having been granted full funding from CONICYT, the Chilean State Agency of Research, in 2013. The Design Phase is starting now and will be completed in late 2014, followed by a construction phase in 2015 and 2016A, with expected Commissioning in 2016B and 2017A.

  5. WINGS: A WIde-field Nearby Galaxy-cluster Survey. II. Deep optical photometry of 77 nearby clusters

    NASA Astrophysics Data System (ADS)

    Varela, J.; D'Onofrio, M.; Marmo, C.; Fasano, G.; Bettoni, D.; Cava, A.; Couch, W. J.; Dressler, A.; Kjærgaard, P.; Moles, M.; Pignatelli, E.; Poggianti, B. M.; Valentinuzzi, T.

    2009-04-01

    Context: This is the second paper of a series devoted to the WIde Field Nearby Galaxy-cluster Survey (WINGS). WINGS is a long term project which is gathering wide-field, multi-band imaging and spectroscopy of galaxies in a complete sample of 77 X-ray selected, nearby clusters (0.04 < z < 0.07) located far from the galactic plane (|b|≥ 20°). The main goal of this project is to establish a local reference for evolutionary studies of galaxies and galaxy clusters. Aims: This paper presents the optical (B,V) photometric catalogs of the WINGS sample and describes the procedures followed to construct them. We have paid special care to correctly treat the large extended galaxies (which includes the brightest cluster galaxies) and the reduction of the influence of the bright halos of very bright stars. Methods: We have constructed photometric catalogs based on wide-field images in B and V bands using SExtractor. Photometry has been performed on images in which large galaxies and halos of bright stars were removed after modeling them with elliptical isophotes. Results: We publish deep optical photometric catalogs (90% complete at V ~ 21.7, which translates to ˜ M^*_V+6 at mean redshift), giving positions, geometrical parameters, and several total and aperture magnitudes for all the objects detected. For each field we have produced three catalogs containing galaxies, stars and objects of “unknown” classification (~6%). From simulations we found that the uncertainty of our photometry is quite dependent of the light profile of the objects with stars having the most robust photometry and de Vaucouleurs profiles showing higher uncertainties and also an additional bias of ~-0.2^m. The star/galaxy classification of the bright objects (V < 20) was checked visually making negligible the fraction of misclassified objects. For fainter objects, we found that simulations do not provide reliable estimates of the possible misclassification and therefore we have compared our data

  6. Development of a Data Reduction Algorithm for Optical Wide Field Patrol (OWL) II: Improving Measurement of Lengths of Detected Streaks

    NASA Astrophysics Data System (ADS)

    Park, Sun-Youp; Choi, Jin; Roh, Dong-Goo; Park, Maru; Jo, Jung Hyun; Yim, Hong-Suh; Park, Young-Sik; Bae, Young-Ho; Park, Jang-Hyun; Moon, Hong-Kyu; Choi, Young-Jun; Cho, Sungki; Choi, Eun-Jung

    2016-09-01

    As described in the previous paper (Park et al. 2013), the detector subsystem of optical wide-field patrol (OWL) provides many observational data points of a single artificial satellite or space debris in the form of small streaks, using a chopper system and a time tagger. The position and the corresponding time data are matched assuming that the length of a streak on the CCD frame is proportional to the time duration of the exposure during which the chopper blades do not obscure the CCD window. In the previous study, however, the length was measured using the diagonal of the rectangle of the image area containing the streak; the results were quite ambiguous and inaccurate, allowing possible matching error of positions and time data. Furthermore, because only one (position, time) data point is created from one streak, the efficiency of the observation decreases. To define the length of a streak correctly, it is important to locate the endpoints of a streak. In this paper, a method using a differential convolution mask pattern is tested. This method can be used to obtain the positions where the pixel values are changed sharply. These endpoints can be regarded as directly detected positional data, and the number of data points is doubled by this result.

  7. An optical design of the wide-field imaging and multi-object spectrograph for an Antarctic infrared telescope

    NASA Astrophysics Data System (ADS)

    Ichikawa, Takashi; Obata, Tomokazu

    2016-08-01

    A design of the wide-field infrared camera (AIRC) for Antarctic 2.5m infrared telescope (AIRT) is presented. The off-axis design provides a 7'.5 ×7'. 5 field of view with 0".22 pixel-1 in the wavelength range of 1 to 5 μm for the simultaneous three-color bands using cooled optics and three 2048×2048 InSb focal plane arrays. Good image quality is obtained over the entire field of view with practically no chromatic aberration. The image size corresponds to the refraction limited for 2.5 m telescope at 2 μm and longer. To enjoy the stable atmosphere with extremely low perceptible water vapor (PWV), superb seeing quality, and the cadence of the polar winter at Dome Fuji on the Antarctic plateau, the camera will be dedicated to the transit observations of exoplanets. The function of a multi-object spectroscopic mode with low spectra resolution (R 50-100) will be added for the spectroscopic transit observation at 1-5 μm. The spectroscopic capability in the environment of extremely low PWV of Antarctica will be very effective for the study of the existence of water vapor in the atmosphere of super earths.

  8. O-6 Optical Property Degradation of the Hubble Space Telescope's Wide Field Camera-2 Pick Off Mirror

    NASA Technical Reports Server (NTRS)

    McNamara, Karen M.; Hughes, D. W.; Lauer, H. V.; Burkett, P. J.; Reed, B. B.

    2011-01-01

    Degradation in the performance of optical components can be greatly affected by exposure to the space environment. Many factors can contribute to such degradation including surface contaminants; outgassing; vacuum, UV, and atomic oxygen exposure; temperature cycling; or combinations of parameters. In-situ observations give important clues to degradation processes, but there are relatively few opportunities to correlate those observations with post-flight ground analyses. The return of instruments from the Hubble Space Telescope (HST) after its final servicing mission in May 2009 provided such an opportunity. Among the instruments returned from HST was the Wide-Field Planetary Camera-2 (WFPC-2), which had been exposed to the space environment for 16 years. This work focuses on the identifying the sources of degradation in the performance of the Pick-off mirror (POM) from WFPC-2. Techniques including surface reflectivity measurements, spectroscopic ellipsometry, FTIR (and ATR-FTIR) analyses, SEM/EDS, X-ray photoelectron spectroscopy (XPS) with and without ion milling, and wet and dry physical surface sampling were performed. Destructive and contact analyses took place only after completion of the non-destructive measurements. Spectroscopic ellipsometry was then repeated to determine the extent of contaminant removal by the destructive techniques, providing insight into the nature and extent of polymerization of the contaminant layer.

  9. Optical multi-frequency swept sensing for wide-field vibration measurement of interior surfaces in biological tissue

    NASA Astrophysics Data System (ADS)

    Choi, S.; Nin, F.; Hibino, H.; Suzuki, T.

    2015-12-01

    Multifrequency sensing technique adopting the wide field heterodyne detection technique is demonstrated for interior surface vibration measurements in thick biological tissue. These arrangements allow obtaining not only 3D tomographic images but also various vibration parameters such as spatial amplitude, phase, and frequency, with high temporal and transverse resolutions over a wide field. The axial resolution and the accuracy of vibration amplitude measurement were estimated to be 2.5 μm and 3 nm, respectively. This wide-field tomographic sensing method can be applied for measuring microdynamics of a variety of biological samples, thus contributing to the progress in life sciences research.

  10. Wide-field optical coherence elastography for intraoperative assessment of tumour margins in breast cancer (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Allen, Wes M.; Chin, Lixin; Sampson, David D.; Kennedy, Brendan F.

    2016-03-01

    Incomplete excision of tumour margins is a major issue in breast-conserving surgery. Currently 20 - 60% of cases require a second surgical procedure required as a result of cancer recurrence. A number of techniques have been proposed to assess margin status, including frozen section analysis and imprint cytology. However, the recurrence rate after using these techniques remains very high. Over the last several years, our group has been developing optical coherence elastography (OCE) as a tool for the intraoperative assessment of tumour margins in breast cancer. We have reported a feasibility study on 65 ex vivo samples from patients undergoing mastectomy or wide local excision demonstrates the potential of OCE in differentiating benign from malignant tissue. In this study, malignant tissue was readily distinguished from surrounding relative tissue by a distinctive heterogeneous pattern in micro-elastograms. To date the largest field of view for a micro-elastogram is 20 x 20mm, however, lumpectomy samples are typically ~50 x 50 x 30mm. For OCE to progress as a useful clinical tool, elastograms must be acquired over larger areas to allow a greater portion of the surface area of lumpectomies to be assessed. Here, we propose a wide-field OCE scanner that utilizes a piezoelectric transducer with an internal diameter of 65mm. In this approach partially overlapped elastograms are stitched together forming a mosaic with overall dimensions of 50 x 50mm in a total acquisition time of 15 - 30 minutes. We present results using this approach on both tissue-mimicking phantoms and tissue, and discuss prospects for shorter acquisitions times.

  11. Dynamic registration of an optical see-through HMD into a wide field-of-view rotorcraft flight simulation environment

    NASA Astrophysics Data System (ADS)

    Viertler, Franz; Hajek, Manfred

    2015-05-01

    To overcome the challenge of helicopter flight in degraded visual environments, current research considers headmounted displays with 3D-conformal (scene-linked) visual cues as most promising display technology. For pilot-in-theloop simulations with HMDs, a highly accurate registration of the augmented visual system is required. In rotorcraft flight simulators the outside visual cues are usually provided by a dome projection system, since a wide field-of-view (e.g. horizontally > 200° and vertically > 80°) is required, which can hardly be achieved with collimated viewing systems. But optical see-through HMDs do mostly not have an equivalent focus compared to the distance of the pilot's eye-point position to the curved screen, which is also dependant on head motion. Hence, a dynamic vergence correction has been implemented to avoid binocular disparity. In addition, the parallax error induced by even small translational head motions is corrected with a head-tracking system to be adjusted onto the projected screen. For this purpose, two options are presented. The correction can be achieved by rendering the view with yaw and pitch offset angles dependent on the deviating head position from the design eye-point of the spherical projection system. Furthermore, it can be solved by implementing a dynamic eye-point in the multi-channel projection system for the outside visual cues. Both options have been investigated for the integration of a binocular HMD into the Rotorcraft Simulation Environment (ROSIE) at the Technische Universitaet Muenchen. Pros and cons of both possibilities with regard on integration issues and usability in flight simulations will be discussed.

  12. KMTNet: a network of 1.6-m wide field optical telescopes installed at three southern observatories

    NASA Astrophysics Data System (ADS)

    Lee, Chung-Uk; Kim, Seung-Lee; Cha, Sang-Mok; Lee, Yongseok; Kim, Dong-Jin; Park, Byeong-Gon; Lee, Dong-Joo; Koo, Jae-Rim; Hong, Kyeongsoo; Lee, Jae Woo; Ryu, Yoon-Hyun; Lim, Beomdu; Lim, Jin-Sun; Gho, Seung-Won; Kim, Min-Jun

    2015-08-01

    Korea Astronomy and Space Science Institute (KASI) have installed three identical 1.6-m telescopes, called Korea Microlensing Telescope Network (KMTNet), which cover 2 x 2 degree field of view with the plate scale of 0.4 arcsec/pixel at three observatories - CTIO, SSO and SAAO in southern hemisphere. The uniqueness of the system is the uninterupted 24-hour monitoring with a wide field optics in southern hemisphere. The telescope adopts prime focus using a parabolic mirror and four spherical flattening lenses. The structural design and driving systems are modified from the degin of 2MASS telescope. The one piece filter-shutter assembly has a sliding shutter and four 310-mm square filters. Each observation system produces a 680MB size image file at site and the images are transfered to KASI data center using the Global Ring Network for Advanced Application Development (GLORIAD) network with the band width of 50Mbps in average. The main science goal of the KMTNet is to discover Earth like extra solar planet using the microlensing technique during bulge season, and 50% of the total observation time is allocated for the science program solely. The other telescope times are allocated for pre-selected seven science programs during non-bulge season. From the test observation, we verify that the most important two requirements are satisfied: 10 arcsec in RMS for the pointing accuracy and 1 arcsec of delivered image quality in I-band. In this presentation, we introduce finally installed system at each observatory and its observational performance obtained from the test observation.

  13. Prime Focus Spectrograph: A very wide-field, massively multiplexed, optical & near-infrared spectrograph for Subaru Telescope

    NASA Astrophysics Data System (ADS)

    Tamura, Naoyuki

    This short article is about Prime Focus Spectrograph (PFS), a very wide-field, massively-multiplexed, and optical & near-infrared (NIR) spectrograph as a next generation facility instrument on Subaru Telescope. More details and updates are available on the PFS official website (http://pfs.ipmu.jp), blog (http://pfs.ipmu.jp/blog/), and references therein. The project, instrument, & timeline PFS will position 2400 fibers to science targets or blank sky in the 1.3 degree field on the Subaru prime focus. These fibers will be quickly (~60sec) reconfigurable and feed the photons during exposures to the Spectrograph System (SpS). SpS consists of 4 modules each of which accommodate ~600 fibers and deliver spectral images ranging from 380nm to 1260nm simultaneously at one exposure via the 3 arms of blue, red, and NIR cameras. The instrument development has been undertaken by the international collaboration at the initiative of Kavli IPMU. The project is now going into the construction phase aiming at system integration and on-sky engineering observations in 2017-2018, and science operation in 2019. The survey design has also been under development envisioning a survey spanning ~300 nights over ~5 years in the framework of Subaru Strategic Program (SSP). The key science areas are: Cosmology, galaxy/AGN evolution, and Galactic Archaeology (GA) (Takada et al. 2014). The cosmology program will be to constrain the nature of dark energy via a survey of emission line galaxies over a comoving volume of 10 Gpc3 at z=0.8-2.4. In the galaxy/AGN program, the wide wavelength coverage of PFS as well as the large field of view will be exploited to characterize the galaxy populations and its clustering properties over a wide redshift range. A survey of color-selected galaxies/AGN at z = 1-2 will be conducted over 20 square degrees yielding a fair sample of galaxies with stellar masses down to ~1010 M ⊙. In the GA program, radial velocities and chemical abundances of stars in the Milky

  14. Prime Focus Spectrograph: A very wide-field, massively multiplexed, optical & near-infrared spectrograph for Subaru Telescope

    NASA Astrophysics Data System (ADS)

    TAMURA, NAOYUKI

    2015-08-01

    PFS (Prime Focus Spectrograph), a next generation facility instrument on Subaru, is a very wide-field, massively-multiplexed, and optical & near-infrared spectrograph. Exploiting the Subaru prime focus, 2400 reconfigurable fibers will be distributed in the 1.3 degree field. The spectrograph will have 3 arms of blue, red, and near-infrared cameras to simultaneously observe spectra from 380nm to 1260nm at one exposure. The development of this instrument has been undertaken by the international collaboration at the initiative of Kavli IPMU. The project is now going into the construction phase aiming at system integration and on-sky commissioning in 2017-2018, and science operation in 2019. In parallel, the survey design has also been developed envisioning a Subaru Strategic Program (SSP) that spans roughly speaking 300 nights over 5 years. The major science areas are three-folds: Cosmology, galaxy/AGN evolution, and Galactic archaeology (GA). The cosmology program will be to constrain the nature of dark energy via a survey of emission line galaxies over a comoving volume of ~10 Gpc^3 in the redshift range of 0.8 < z < 2.4. In the GA program, radial velocities and chemical abundances of stars in the Milky Way, dwarf spheroidal galaxies, and M31 will be used to understand the past assembly histories of those galaxies and the structures of their dark matter halos. Spectra will be taken for ~1 million stars as faint as V = 22 therefore out to large distances from the Sun. For the extragalactic program, our simulations suggest the wide wavelength coverage of PFS will be particularly powerful in probing the galaxy populations and its clustering properties over a wide redshift range. We will conduct a survey of color-selected 1 < z < 2 galaxies and AGN over 20 square degrees down to J = 23.4, yielding a fair sample of galaxies with stellar masses above ˜10^10 solar masses. Further, PFS will also provide unique spectroscopic opportunities even in the era of Euclid, LSST

  15. Development of an optical imaging platform for functional imaging of small animals using wide-field excitation

    PubMed Central

    Venugopal, Vivek; Chen, Jin; Intes, Xavier

    2010-01-01

    The design and characterization of a time-resolved functional imager using a wide-field excitation scheme for small animal imaging is described. The optimal operation parameters are established based on phantom studies. The performance of the platform for functional imaging and the simultaneous 3D reconstruction of absorption and scattering coefficients is investigated in vitro. PMID:21258454

  16. Wide field of view telescope

    DOEpatents

    Ackermann, Mark R.; McGraw, John T.; Zimmer, Peter C.

    2008-01-15

    A wide field of view telescope having two concave and two convex reflective surfaces, each with an aspheric surface contour, has a flat focal plane array. Each of the primary, secondary, tertiary, and quaternary reflective surfaces are rotationally symmetric about the optical axis. The combination of the reflective surfaces results in a wide field of view in the range of approximately 3.8.degree. to approximately 6.5.degree.. The length of the telescope along the optical axis is approximately equal to or less than the diameter of the largest of the reflective surfaces.

  17. Invited Article: First flight in space of a wide-field-of-view soft x-ray imager using lobster-eye optics: Instrument description and initial flight results.

    PubMed

    Collier, Michael R; Porter, F Scott; Sibeck, David G; Carter, Jenny A; Chiao, Meng P; Chornay, Dennis J; Cravens, Thomas E; Galeazzi, Massimiliano; Keller, John W; Koutroumpa, Dimitra; Kujawski, Joseph; Kuntz, Kip; Read, Andy M; Robertson, Ina P; Sembay, Steve; Snowden, Steven L; Thomas, Nicholas; Uprety, Youaraj; Walsh, Brian M

    2015-07-01

    We describe the development, launch into space, and initial results from a prototype wide field-of-view soft X-ray imager that employs lobster-eye optics and targets heliophysics, planetary, and astrophysics science. The sheath transport observer for the redistribution of mass is the first instrument using this type of optics launched into space and provides proof-of-concept for future flight instruments capable of imaging structures such as the terrestrial cusp, the entire dayside magnetosheath from outside the magnetosphere, comets, the Moon, and the solar wind interaction with planetary bodies like Venus and Mars [Kuntz et al., Astrophys. J. (in press)].

  18. Invited Article: First flight in space of a wide-field-of-view soft x-ray imager using lobster-eye optics: Instrument description and initial flight results

    NASA Astrophysics Data System (ADS)

    Collier, Michael R.; Porter, F. Scott; Sibeck, David G.; Carter, Jenny A.; Chiao, Meng P.; Chornay, Dennis J.; Cravens, Thomas E.; Galeazzi, Massimiliano; Keller, John W.; Koutroumpa, Dimitra; Kujawski, Joseph; Kuntz, Kip; Read, Andy M.; Robertson, Ina P.; Sembay, Steve; Snowden, Steven L.; Thomas, Nicholas; Uprety, Youaraj; Walsh, Brian M.

    2015-07-01

    We describe the development, launch into space, and initial results from a prototype wide field-of-view soft X-ray imager that employs lobster-eye optics and targets heliophysics, planetary, and astrophysics science. The sheath transport observer for the redistribution of mass is the first instrument using this type of optics launched into space and provides proof-of-concept for future flight instruments capable of imaging structures such as the terrestrial cusp, the entire dayside magnetosheath from outside the magnetosphere, comets, the Moon, and the solar wind interaction with planetary bodies like Venus and Mars [Kuntz et al., Astrophys. J. (in press)].

  19. Active optics and the axisymmetric case: MINITRUST wide-field three-reflection telescopes with mirrors aspherized from tulip and vase forms

    NASA Astrophysics Data System (ADS)

    Lemaitre, Gerard R.; Montiel, Pierre; Joulie, Patrice; Dohlen, Kjetil; Lanzoni, Patrick

    2004-09-01

    Wide-field astronomy requires larger size telescopes. Compared to the catadioptric Schmidt, the optical properties of a three mirror telescope provides significant advantages. (1) The flat field design is anastigmatic at any wavelength, (2) the system is extremely compact -- four times shorter than a Schmidt -- and, (3) compared to a Schmidt with refractive corrector -- requiring the polishing of three optical surfaces --, the presently proposed Modified-Rumsey design uses all of eight available free parameters of a flat fielded anastigmatic three mirror telescope for mirrors generated by active optics methods. Compared to a Rumsey design, these parameters include the additional slope continuity condition at the primary-tertiary link for in-situ stressing and aspherization from a common sphere. Then, active optics allows the polishing of only two spherical surfaces: the combined primary-tertiary mirror and the secondary mirror. All mirrors are spheroids of the hyperboloid type. This compact system is of interest for space and ground-based astronomy and allows to built larger wide-field telescopes such as demonstrated by the design and construction of identical telescopes MINITRUST-1 and -2, f/5 - 2° FOV, consisting of an in-situ stressed double vase form primary-tertiary and of a stress polished tulip form secondary. Optical tests of these telescopes, showing diffraction limited images, are presented.

  20. Wide-Field Plate Database

    NASA Astrophysics Data System (ADS)

    Tsvetkov, M. K.; Stavrev, K. Y.; Tsvetkova, K. P.; Semkov, E. H.; Mutatov, A. S.

    The Wide-Field Plate Database (WFPDB) and the possibilities for its application as a research tool in observational astronomy are presented. Currently the WFPDB comprises the descriptive data for 400 000 archival wide field photographic plates obtained with 77 instruments, from a total of 1 850 000 photographs stored in 269 astronomical archives all over the world since the end of last century. The WFPDB is already accessible for the astronomical community, now only in batch mode through user requests sent by e-mail. We are working on on-line interactive access to the data via INTERNET from Sofia and parallel from the Centre de Donnees Astronomiques de Strasbourg. (Initial information can be found on World Wide Web homepage URL http://www.wfpa.acad.bg.) The WFPDB may be useful in studies of a variety of astronomical objects and phenomena, andespecially for long-term investigations of variable objects and for multi-wavelength research. We have analysed the data in the WFPDB in order to derive the overall characteristics of the totality of wide-field observations, such as the sky coverage, the distributions by observation time and date, by spectral band, and by object type. We have also examined the totality of wide-field observations from point of view of their quality, availability and digitisation. The usefulness of the WFPDB is demonstrated by the results of identification and investigation of the photometrical behaviour of optical analogues of gamma-ray bursts.

  1. Prime Focus Spectrograph (PFS): A Very Wide-Field, Massively Multi-Object, Optical and Near-Infrared Fiber-Fed Spectrograph on the Subaru Telescope

    NASA Astrophysics Data System (ADS)

    Tamura, N.; PFS Collaboration

    2016-10-01

    PFS (Prime Focus Spectrograph), a next generation facility instrument on the Subaru Telescope, is a very wide-field, massively multiplexed, optical and near-infrared fiber spectrograph: 2400 reconfigurable fibers are distributed in the 1.3 deg. field of view at the prime focus of the Subaru Telescope. The spectrograph system has blue, red, and near-infrared cameras to simultaneously observe spectra from 380 nm to 1260 nm in one exposure. The project is now entering the construction phase, aiming at starting system integration and commissioning in 2017-2018, and science operation in 2019.

  2. Wide-field optical detection of nanoparticles using on-chip microscopy and self-assembled nanolenses

    NASA Astrophysics Data System (ADS)

    Mudanyali, Onur; McLeod, Euan; Luo, Wei; Greenbaum, Alon; Coskun, Ahmet F.; Hennequin, Yves; Allier, Cédric P.; Ozcan, Aydogan

    2013-03-01

    The direct observation of nanoscale objects is a challenging task for optical microscopy because the scattering from an individual nanoparticle is typically weak at optical wavelengths. Electron microscopy therefore remains one of the gold standard visualization methods for nanoparticles, despite its high cost, limited throughput and restricted field-of-view. Here, we describe a high-throughput, on-chip detection scheme that uses biocompatible wetting films to self-assemble aspheric liquid nanolenses around individual nanoparticles to enhance the contrast between the scattered and background light. We model the effect of the nanolens as a spatial phase mask centred on the particle and show that the holographic diffraction pattern of this effective phase mask allows detection of sub-100 nm particles across a large field-of-view of >20 mm2. As a proof-of-concept demonstration, we report on-chip detection of individual polystyrene nanoparticles, adenoviruses and influenza A (H1N1) viral particles.

  3. Comparison of multispectral wide-field optical imaging modalities to maximize image contrast for objective discrimination of oral neoplasia

    NASA Astrophysics Data System (ADS)

    Roblyer, Darren; Kurachi, Cristina; Stepanek, Vanda; Schwarz, Richard A.; Williams, Michelle D.; El-Naggar, Adel K.; Lee, J. Jack; Gillenwater, Ann M.; Richards-Kortum, Rebecca

    2010-11-01

    Multispectral widefield optical imaging has the potential to improve early detection of oral cancer. The appropriate selection of illumination and collection conditions is required to maximize diagnostic ability. The goals of this study were to (i) evaluate image contrast between oral cancer/precancer and non-neoplastic mucosa for a variety of imaging modalities and illumination/collection conditions, and (ii) use classification algorithms to evaluate and compare the diagnostic utility of these modalities to discriminate cancers and precancers from normal tissue. Narrowband reflectance, autofluorescence, and polarized reflectance images were obtained from 61 patients and 11 normal volunteers. Image contrast was compared to identify modalities and conditions yielding greatest contrast. Image features were extracted and used to train and evaluate classification algorithms to discriminate tissue as non-neoplastic, dysplastic, or cancer; results were compared to histologic diagnosis. Autofluorescence imaging at 405-nm excitation provided the greatest image contrast, and the ratio of red-to-green fluorescence intensity computed from these images provided the best classification of dysplasia/cancer versus non-neoplastic tissue. A sensitivity of 100% and a specificity of 85% were achieved in the validation set. Multispectral widefield images can accurately distinguish neoplastic and non-neoplastic tissue; however, the ability to separate precancerous lesions from cancers with this technique was limited.

  4. A Wide-Field Narrowband Optical Survey of the Braid Nebula Star Formation Region in Cygnus OB7

    NASA Astrophysics Data System (ADS)

    Magakian, Tigran Yu.; Nikogossian, Elena H.; Aspin, Colin; Pyo, Tae-Soo; Khanzadyan, Tigran; Movsessian, Tigran; Smith, Michael D.; Mitchison, Sharon; Davis, Chris J.; Beck, Tracy L.; Moriarty-Schieven, Gerald H.

    2010-03-01

    We study the population of Herbig-Haro (HH) flows and jets in an area of Cygnus OB7 designated the Braid Nebula star formation region. This complex forms part of the L 1003 dark cloud, and hosts two FU Orionis (FUor)-like objects as well as several other active young stars. To trace outflow activity and to relate both known and newly discovered flows to young star hosts we intercompare new, deep, narrowband Hα and [S II] optical images taken on the Subaru 8 m Telescope on Mauna Kea, Hawaii. Our images show that there is considerable outflow and jet activity in this region suggesting the presence of an extensive young star population. We confirm that both of the FUor-like objects drive extensive HH flows and document further members of the flows in both objects. The L 1003 star formation complex is a highly kinematically active region with young stars in several different stages of evolution. We trace collimated outflows from numerous young stars although the origin of some HH objects remains elusive. Based on data collected at the Subaru Telescope, which is operated by the National Astronomical Observatory of Japan.

  5. A WIDE-FIELD NARROWBAND OPTICAL SURVEY OF THE BRAID NEBULA STAR FORMATION REGION IN CYGNUS OB7

    SciTech Connect

    Magakian, Tigran Yu.; Nikogossian, Elena H.; Movsessian, Tigran; Aspin, Colin; Pyo, Tae-Soo; Khanzadyan, Tigran; Smith, Michael D.; Mitchison, Sharon; Davis, Chris J.; Beck, Tracy L.; Moriarty-Schieven, Gerald H. E-mail: elena@bao.sci.am E-mail: pyo@subaru.naoj.org E-mail: smm23@kent.ac.uk E-mail: c.davis@jach.hawaii.edu E-mail: gerald.schieven@nrc-cnrc.gc.ca

    2010-03-15

    We study the population of Herbig-Haro (HH) flows and jets in an area of Cygnus OB7 designated the Braid Nebula star formation region. This complex forms part of the L 1003 dark cloud, and hosts two FU Orionis (FUor)-like objects as well as several other active young stars. To trace outflow activity and to relate both known and newly discovered flows to young star hosts we intercompare new, deep, narrowband H{alpha} and [S II] optical images taken on the Subaru 8 m Telescope on Mauna Kea, Hawaii. Our images show that there is considerable outflow and jet activity in this region suggesting the presence of an extensive young star population. We confirm that both of the FUor-like objects drive extensive HH flows and document further members of the flows in both objects. The L 1003 star formation complex is a highly kinematically active region with young stars in several different stages of evolution. We trace collimated outflows from numerous young stars although the origin of some HH objects remains elusive.

  6. BRIGHTEST X-RAY CLUSTERS OF GALAXIES IN THE CFHTLS WIDE FIELDS: CATALOG AND OPTICAL MASS ESTIMATOR

    SciTech Connect

    Mirkazemi, M.; Finoguenov, A.; Lerchster, M.; Erfanianfar, G.; Seitz, S.; Pereira, M. J.; Egami, E.; Tanaka, M.; Brimioulle, F.; Kettula, K.; McCracken, H. J.; Mellier, Y.; Kneib, J. P.; Rykoff, E.; Erben, T.; Taylor, J. E.

    2015-01-20

    The Canada-France-Hawaii Telescope Legacy Survey (CFHTLS) presents a unique data set for weak-lensing studies, having high-quality imaging and deep multiband photometry. We have initiated an XMM-CFHTLS project to provide X-ray observations of the brightest X-ray-selected clusters within the wide CFHTLS area. Performance of these observations and the high quality of CFHTLS data allow us to revisit the identification of X-ray sources, introducing automated reproducible algorithms, based on the multicolor red sequence finder. We have also introduced a new optical mass proxy. We provide the calibration of the red sequence observed in the Canada-France-Hawaii filters and compare the results with the traditional single-color red sequence and photo-z. We test the identification algorithm on the subset of highly significant XMM clusters and identify 100% of the sample. We find that the integrated z-band luminosity of the red sequence galaxies correlates well with the X-ray luminosity, with a surprisingly small scatter of 0.20 dex. We further use the multicolor red sequence to reduce spurious detections in the full XMM and ROSAT All-Sky Survey (RASS) data sets, resulting in catalogs of 196 and 32 clusters, respectively. We made spectroscopic follow-up observations of some of these systems with HECTOSPEC and in combination with BOSS DR9 data. We also describe the modifications needed to the source detection algorithm in order to maintain high purity of extended sources in the shallow X-ray data. We also present the scaling relation between X-ray luminosity and velocity dispersion.

  7. First ever cross comparison of thermospheric wind measured by narrow- and wide-field optical Doppler spectroscopy

    NASA Astrophysics Data System (ADS)

    Dhadly, M. S.; Meriwether, J.; Conde, M.; Hampton, D.

    2015-11-01

    We present the first ever cross comparisons of F region horizontal neutral wind measurements taken using two different types of optical Doppler spectrometer: all-sky scanning Doppler imagers (SDI) and narrow-field Fabry-Perot interferometers (NFPIs). Horizontal neutral winds were inferred using bistatic observations from three NFPIs, together with monostatic and bistatic observations from two SDIs. All instruments were located in Alaska. Cross comparisons were made for a total of seven nights in January and February 2010. The results show a high degree of correlation between the diurnal behaviors of the line-of-sight (LOS) winds measured by both instruments. The SDI and NFPI LOS wind time series also often contained high-frequency fluctuations with similar overall characteristics, strongly suggesting that these fluctuations were geophysical in origin. However, the amplitude of the high-frequency component was stronger in the NFPI LOS wind than in the SDI data. Even the smallest SDI angular resolution element is much larger than the NFPI field of view, suggesting that its relative insensitivity to high frequencies is because these fluctuations are associated with local-scale structures whose spatial extent is smaller than ˜40 km spanned by the smallest SDI viewing field. Upon fitting vectors to the LOS wind data, close agreement was found between the wind components estimated by the two types of instrument. Discrepancies that did arise occurred most often when the neutral wind speed was weak, suggesting that conditions capable of driving higher neutral wind speeds also suppressed the development of small-scale structures in the thermospheric neutral wind fields.

  8. Design and characterization of a nano-encapsulated self-referenced fluorescent nitric oxide sensor for wide-field optical imaging.

    PubMed

    Zhang, Guodong; Shu, Florence P; Robinson, Charles J

    2007-01-01

    A nano-encapsulated fluorescence dye DAF-2 sensor that is specifically sensitive to nitric oxide (NO) was fabricated by using an electrostatic layer-by-layer (LbL) self-assembly technique. Fluorescence calibrations of the NO sensor were collected by a wide-field optical imaging system and a fluorescence spectrometer using NO standards generated by the self decomposition of S-nitrosol-acetyl-penicillamine (SNAP). The NO sensor consists of two fluorescence dyes, indicator DAF-2 and a reference R-PE. The two dyes share the same excitation, and have different emission wavelengths. The calibration results show that the indicator fluorescence intensity increases with NO standard solution additions, while the reference fluorescence intensity does not. The encapsulation reduced the NO sensor detection limit, but it is still within physiological level of NO. This sensor design can also achieve ratiometric self referencing with very little leaching effect.

  9. Future Optical Networks

    NASA Astrophysics Data System (ADS)

    O'Mahony, Michael J.; Politi, Christina; Klonidis, Dimitrios; Nejabati, Reza; Simeonidou, Dimitra

    2006-12-01

    This paper presents views on the future of optical networking. A historical look at the emergence of optical networking is first taken, followed by a discussion on the drivers pushing for a new and pervasive network, which is based on photonics and can satisfy the needs of a broadening base of residential, business, and scientific users. Regional plans and targets for optical networking are reviewed to understand which current approaches are judged important. Today, two thrusts are driving separate optical network infrastructure models, namely 1) the need by nations to provide a ubiquitous network infrastructure to support all the future services and telecommunication needs of residential and business users and 2) increasing demands by the scientific community for networks to support their requirements with respect to large-scale data transport and processing. This paper discusses these network models together with the key enabling technologies currently being considered for future implementation, including optical circuit, burst and packet switching, and optical code-division multiplexing. Critical subsystem functionalities are also reviewed. The discussion considers how these separate models might eventually merge to form a global optical network infrastructure.

  10. Reflection, phase and en- face sectional imaging of scattering objects using quasi-single-shot wide-field optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Anna, Tulsi; Kimura, Satoshi; Mehta, Dalip Singh; Sato, Manabu

    2015-10-01

    We report a quasi-single-shot wide-field optical coherence tomography system that enables to measure the reflection, phase and en- face OCT images from the same setup using the glass jig. The jig consisting of a wedge glass substrate and a glue dot is contacted to the tissue surfaces, and the data within glue dot is used to reduce the phase noise of the interference signal. The reconstructed image size of the object was 4.0 mm × 4.3 mm. The standard deviation (STD) of the phase variation was minimized by 54 % and obtained to be 0.027 rad for the poke tissue. The corresponding STD in optical path length change was measured to be 1.4 nm. The refractive index of the water and poke tissue at the surface is also evaluated as 1.36 and 1.39, respectively, using reflection intensity images. Further, the en- face sectional images of the tissue sample are also measured.

  11. Instrumentation of LOTIS--Livermore Optical Transient Imaging System: a fully automated wide-field-of-view telescope system searching for simultaneous optical counterparts of gamma-ray bursts

    NASA Astrophysics Data System (ADS)

    Park, Hye-Sook; Ables, Elden; Barthelmy, Scott D.; Bionta, Richard M.; Ott, Linda L.; Parker, Eric L.; Williams, George G.

    1998-07-01

    LOTIS is a rapidly slewing wide-field-of-viewtelescope which was designed and constructed to search for simultaneous gamma- ray burst (GRB) optical counterparts. This experiment requires a rapidly slewing (less than 10 sec), wide-field-of-view (greater than 15 degrees celsius), automatic and dedicated telescope. LOTIS utilizes commercial tele-photo lenses and custom 2048 X 2048 CCD cameras to view a 17.6 X 17.6 degree field of view. It can point to any part of the sky within 5 sec and is fully automated. It is connected via Internet socket to the GRB coordinate distribution network which analyzes telemetry from the satellite and delivers GRB coordinate information in real-time. LOTIS started routine operation in Oct. 1996. In the idle time between GRB triggers, LOTIS systematically surveys the entire available sky every night for new optical transients. This paper will describe the system design and performance.

  12. A processing work-flow for measuring erythrocytes velocity in extended vascular networks from wide field high-resolution optical imaging data.

    PubMed

    Deneux, Thomas; Takerkart, Sylvain; Grinvald, Amiram; Masson, Guillaume S; Vanzetta, Ivo

    2012-02-01

    Comprehensive information on the spatio-temporal dynamics of the vascular response is needed to underpin the signals used in hemodynamics-based functional imaging. It has recently been shown that red blood cells (RBCs) velocity and its changes can be extracted from wide-field optical imaging recordings of intrinsic absorption changes in cortex. Here, we describe a complete processing work-flow for reliable RBC velocity estimation in cortical networks. Several pre-processing steps are implemented: image co-registration, necessary to correct for small movements of the vasculature, semi-automatic image segmentation for fast and reproducible vessel selection, reconstruction of RBC trajectories patterns for each micro-vessel, and spatio-temporal filtering to enhance the desired data characteristics. The main analysis step is composed of two robust algorithms for estimating the RBCs' velocity field. Vessel diameter and its changes are also estimated, as well as local changes in backscattered light intensity. This full processing chain is implemented with a software suite that is freely distributed. The software uses efficient data management for handling the very large data sets obtained with in vivo optical imaging. It offers a complete and user-friendly graphical user interface with visualization tools for displaying and exploring data and results. A full data simulation framework is also provided in order to optimize the performances of the algorithm with respect to several characteristics of the data. We illustrate the performance of our method in three different cases of in vivo data. We first document the massive RBC speed response evoked by a spreading depression in anesthetized rat somato-sensory cortex. Second, we show the velocity response elicited by a visual stimulation in anesthetized cat visual cortex. Finally, we report, for the first time, visually-evoked RBC speed responses in an extended vascular network in awake monkey extrastriate cortex.

  13. ROSAT wide field camera mirrors.

    PubMed

    Willingale, R

    1988-04-15

    The ROSAT wide field camera (WFC) is an XUV telescope operating in the 12-250-eV energy band. The mirror system utilizes Wolter-Schwarzschild type I (WS I) grazing incidence optics with a focal length of 525 mm, comprised of three nested aluminum shells with an outermost diameter of 576 mm providing a geometric aperture area of 456 cm(2). The reflecting surfaces are electroless nickel plated and coated with gold to enhance their reflectivity in the XUV. The mirrors have undergone full aperture optical testing, narrow beam XUV testing, and full aperture XUV testing. Measurements of the reflectivity are compared to theoretical values derived from the optical constants of gold in the XUV range. Analysis of the focused distribution is used to estimate the surface roughness and figuring errors of the polished surfaces. The results are compared to the mechanical metrology data collected during manufacture of the shells and the power spectral density of the reflecting surfaces is found to have a power-law form.

  14. ROSAT Wide Field Camera Mirrors

    NASA Astrophysics Data System (ADS)

    Willingale, R.

    1988-08-01

    The ROSAT wide field camera (WFC) is an XUV telescope operating in the 12-250-eV energy band. The mirror system utilizes Wolter-Schwarzschild type I (WSI) grazing incidence optics with a focal length of 525 mm, comprised of three nested aluminum shells with an outermost diameter of 576 mm providing a geometric aperture area of 456 cm2. The reflecting surfaces are electroless nickel plated and coated with gold to enhance their reflectivity in the XUV. The mirrors have undergone full aperture optical testing, narrow beam XUV testing, and full aperture XUV testing. Measurements of the reflectivity are compared to theoretical values derived from the optical constants of gold in the XUV range. Analysis of the focused distribution is used to estimate the surface roughness and figuring errors of the polished surfaces. The results are compared to the mechanical metrology data collected during manufacture of the shells and the power spectral density of the reflecting surfaces is found to have a power-law form.

  15. Wide-field TCSPC: methods and applications

    NASA Astrophysics Data System (ADS)

    Hirvonen, Liisa M.; Suhling, Klaus

    2017-01-01

    Time-correlated single photon counting (TCSPC) is a widely used, robust and mature technique to measure the photon arrival time in applications such as fluorescence spectroscopy and microscopy, LIDAR and optical tomography. In the past few years there have been significant developments with wide-field TCSPC detectors, which can record the position as well as the arrival time of the photon simultaneously. In this review, we summarise different approaches used in wide-field TCSPC detection, and discuss their merits for different applications, with emphasis on fluorescence lifetime imaging.

  16. Future Optical Communications Systems

    DTIC Science & Technology

    2008-06-01

    Networking Equipment Revenue and Forecast, 2000-2017 Sources: KMI, Infonetics, Ovum -RHK, OIDA member companies, TIA, IDC, CIR, Gartner, Dell’Oro, Aventis...quarter seasonality marks a re- turn to normal, established business patterns. Figure 10: Optical Transport Equipment Market ($M) Source: Ovum ...Goldman Sachs Optical Transceivers Figure 14 shows the optical transceiver market and forecast from 2000 to 2011. Ovum forecasts that Ethernet

  17. Real-time turbulence profiling with a pair of laser guide star Shack-Hartmann wavefront sensors for wide-field adaptive optics systems on large to extremely large telescopes.

    PubMed

    Gilles, L; Ellerbroek, B L

    2010-11-01

    Real-time turbulence profiling is necessary to tune tomographic wavefront reconstruction algorithms for wide-field adaptive optics (AO) systems on large to extremely large telescopes, and to perform a variety of image post-processing tasks involving point-spread function reconstruction. This paper describes a computationally efficient and accurate numerical technique inspired by the slope detection and ranging (SLODAR) method to perform this task in real time from properly selected Shack-Hartmann wavefront sensor measurements accumulated over a few hundred frames from a pair of laser guide stars, thus eliminating the need for an additional instrument. The algorithm is introduced, followed by a theoretical influence function analysis illustrating its impulse response to high-resolution turbulence profiles. Finally, its performance is assessed in the context of the Thirty Meter Telescope multi-conjugate adaptive optics system via end-to-end wave optics Monte Carlo simulations.

  18. Wide Field Instrument Adjutant Scientist

    NASA Astrophysics Data System (ADS)

    Spergel, David

    As Wide Field Instrument Adjutant Scientist, my goal will be to maximize the science capability of the mission in a cost-contained environment. I hope to work with the HQ, project and the FSWG to assure mission success. I plan to play a leadership role in communicating the WFIRST science capabilities to the astronomy community , obtain input from both science teams and the broader community that help derive performance requirements and calibration metrics. I plan to focus on developing the observing program for the deep fields and focus on using them to calibrate instrument performance and capabilities. I plan to organize workshops that will bring together WFIRST team members with astronomers working on LSST, Euclid, JWST, and the ELTs to maximize combined science return. I am also eager to explore the astrometric and stellar seismology capabilities of the instrument with a goal of maximizing science return without affecting science requirements.

  19. The LOFT wide field monitor

    NASA Astrophysics Data System (ADS)

    Brandt, S.; Hernanz, M.; Alvarez, L.; Azzarello, P.; Barret, D.; Bozzo, E.; Budtz-Jørgensen, C.; Campana, R.; del Monte, E.; Donnarumma, I.; Evangalista, Y.; Feroci, M.; Galvez Sanchez, J. L.; Götz, D.; Hansen, F.; den Herder, J. W.; Hudec, R.; Huovelin, J.; Karelin, D.; Korpela, S.; Lund, N.; Orleanski, P.; Pohl, M.; Rashevski, A.; Santangelo, A.; Schanne, S.; Schmid, C.; Suchy, S.; Tenzer, C.; Vacchi, A.; Wilms, J.; Zampa, G.; Zampa, N.; in't Zand, J.; Zdziarski, A.

    2012-09-01

    LOFT (Large Observatory For x-ray Timing) is one of the four missions selected in 2011 for assessment study for the ESA M3 mission in the Cosmic Vision program, expected to be launched in 2024. The LOFT mission will carry two instruments with their prime sensitivity in the 2-30 keV range: a 10 m2 class large area detector (LAD) with a <1° collimated field of view and a wide field monitor (WFM) instrument based on the coded mask principle, providing coverage of more than 1/3 of the sky. The LAD will provide an effective area ~20 times larger than any previous mission and will by timing studies be able to address fundamental questions about strong gravity in the vicinity of black holes and the equation of state of nuclear matter in neutron stars. The prime goal of the WFM will be to detect transient sources to be observed by the LAD. However, with its wide field of view and good energy resolution of <300 eV, the WFM will be an excellent monitoring instrument to study long term variability of many classes of X-ray sources. The sensitivity of the WFM will be 2.1 mCrab in a one day observation, and 270 mCrab in 3s in observations of in the crowded field of the Galactic Center. The high duty cycle of the instrument will make it an ideal detector of fast transient phenomena, like X-ray bursters, soft gamma repeaters, terrestrial gamma flashes, and not least provide unique capabilities in the study of gamma ray bursts. A dedicated burst alert system will enable the distribution to the community of ~100 gamma ray burst positions per year with a ~1 arcmin location accuracy within 30 s of the burst. This paper provides an overview of the design, configuration, and capabilities of the LOFT WFM instrument.

  20. Gemini Frontier Fields: Wide-field Adaptive Optics Ks-band Imaging of the Galaxy Clusters MACS J0416.1-2403 and Abell 2744

    NASA Astrophysics Data System (ADS)

    Schirmer, M.; Carrasco, E. R.; Pessev, P.; Garrel, V.; Winge, C.; Neichel, B.; Vidal, F.

    2015-04-01

    We have observed two of the six Frontier Fields galaxy clusters, MACS J0416.1-2403 and Abell 2744, using the Gemini Multi-Conjugate Adaptive Optics System (GeMS) and the Gemini South Adaptive Optics Imager (GSAOI). With 0.″ 08-0.″ 10 FWHM our data are nearly diffraction-limited over a 100\\prime\\prime × 100\\prime\\prime wide area. GeMS/GSAOI complements the Hubble Space Telescope (HST) redwards of 1.6 μm with twice the angular resolution. We reach a 5σ depth of {{K}s}˜ 25.6 mag (AB) for compact sources. In this paper, we describe the observations, data processing, and initial public data release. We provide fully calibrated, co-added images matching the native GSAOI pixel scale as well as the larger plate scales of the HST release, adding to the legacy value of the Frontier Fields. Our work demonstrates that even for fields at high galactic latitude where natural guide stars are rare, current multi-conjugated adaptive optics technology at 8 m telescopes has opened a new window on the distant universe. Observations of a third Frontier Field, Abell 370, are planned. Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the Science and Technology Facilities Council (United Kingdom), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), Ministério da Ciência, Tecnologia e Inovação (Brazil) and Ministerio de Ciencia, Tecnología e Innovación Productiva (Argentina). Based on observations made with ESO Telescopes at the La Silla and Paranal Observatories, Chile.

  1. Optical electrocorticogram (OECoG) using wide-field calcium imaging reveals the divergence of neuronal and glial activity during acute rodent seizures.

    PubMed

    Daniel, Andy G S; Laffont, Philippe; Zhao, Mingrui; Ma, Hongtao; Schwartz, Theodore H

    2015-08-01

    The role of glia in epilepsy has been widely debated. Using in vivo bulk loading of calcium dyes, we imaged neuronal and glial activity in an acute pharmacologic rodent model of neocortical seizures. Optical calcium-based ECoG maps revealed that neuronal waves propagated rapidly and remained mostly confined to the seizure focus. Glial waves were triggered by ictal onset but propagated slowly in a stereotypical fashion far beyond the seizure focus. Although related at their onset, the divergence of these two phenomena during seizure evolution calls into question their interdependence and the criticality of the role of glia in seizure onset and neurovascular coupling. This article is part of a Special Issue entitled "Status Epilepticus".

  2. Measurement of signal intensity depth profiles in rat brains with cardiac arrest maintaining primary temperature by wide-field optical coherence tomography.

    PubMed

    Sato, Manabu; Nomura, Daisuke; Tsunenari, Takashi; Nishidate, Izumi

    2010-09-10

    We have already reported that after an injection for euthanasia, the signal intensity of optical coherence tomography (OCT) images are 2.7 times increased before cardiac arrest (CA) using OCT and rat brains without temperature control to show the potential of OCT to monitor tissue viability in brains [Appl. Opt.48, 4354 (2009)APOPAI0003-693510.1364/AO.48.004354]. In this paper, we similarly measured maintaining the primary temperature of rat brains. It was confirmed that when maintaining the primary temperature, the time courses of the ratios of signal intensity (RSIs) were almost the same as those without temperature control. RSIs after CA varied from 1.6 to 4.5 and depended on positions measured in tissues. These results mean that the OCT technique has clinical potential for applications to monitor or diagnose a focal degraded area, such as cerebral infarctions due to focal ischemia in brains.

  3. Standoff Laser-Induced Breakdown Spectroscopy (LIBS) using a Miniature Wide Field of View Spatial Heterodyne Spectrometer with Sub-Microsteradian Collection Optics.

    PubMed

    Barnett, Patrick D; Lamsal, Nirmal; Angel, S Michael

    2017-01-01

    A spatial heterodyne spectrometer (SHS) is described for standoff laser-induced breakdown spectroscopy (LIBS) measurements. The spatial heterodyne LIBS spectrometer (SHLS) is a diffraction grating based interferometer with no moving parts that offers a very large field of view, high light throughput, and high spectral resolution in a small package. The field of view of the SHLS spectrometer is shown to be ∼1° in standoff LIBS measurements. In the SHLS system described here, the collection aperture was defined by the 10 mm diffraction gratings in the SHS and standoff LIBS measurements were made up to 20 m with no additional collection optics, corresponding to a collection solid angle of 0.2 μsr, or f/2000, and also using a small telescope to increase the collection efficiency. The use of a microphone was demonstrated to rapidly optimize laser focus for 20 m standoff LIBS measurements.

  4. The Ooty Wide Field Array

    NASA Astrophysics Data System (ADS)

    Subrahmanya, C. R.; Manoharan, P. K.; Chengalur, Jayaram N.

    2017-03-01

    We describe here an ongoing upgrade to the legacy Ooty Radio Telescope (ORT). The ORT is a cylindrical parabolic cylinder 530 m × 30 m in size operating at a frequency of 326.5 (or z˜3.35 for the HI 21-cm line). The telescope has been constructed on a North-South hill slope whose gradient is equal to the latitude of the hill, making it effectively equatorially mounted. The feed consists of an array of 1056 dipoles. The key feature of this upgrade is the digitization and cross-correlation of the signals of every set of 4-dipoles. This converts the ORT into a 264 element interferometer with a field-of-view of 2∘×27.4∘cos( δ). This upgraded instrument is called the Ooty Wide Field Array (OWFA). This paper briefly describes the salient features of the upgrade, as well as its main science drivers. There are three main science drivers viz. (1) observations of the large scale distribution of HI in the post-reionization era, (2) studies of the propagation of plasma irregularities through the inner heliosphere and (3) blind surveys for transient sources. More details on the upgrade, as well as on the expected science uses can be found in other papers in this special issue.

  5. Long-range and wide field of view optical coherence tomography for in vivo 3D imaging of large volume object based on akinetic programmable swept source

    PubMed Central

    Song, Shaozhen; Xu, Jingjiang; Wang, Ruikang K.

    2016-01-01

    Current optical coherence tomography (OCT) imaging suffers from short ranging distance and narrow imaging field of view (FOV). There is growing interest in searching for solutions to these limitations in order to expand further in vivo OCT applications. This paper describes a solution where we utilize an akinetic swept source for OCT implementation to enable ~10 cm ranging distance, associated with the use of a wide-angle camera lens in the sample arm to provide a FOV of ~20 x 20 cm2. The akinetic swept source operates at 1300 nm central wavelength with a bandwidth of 100 nm. We propose an adaptive calibration procedure to the programmable akinetic light source so that the sensitivity of the OCT system over ~10 cm ranging distance is substantially improved for imaging of large volume samples. We demonstrate the proposed swept source OCT system for in vivo imaging of entire human hands and faces with an unprecedented FOV (up to 400 cm2). The capability of large-volume OCT imaging with ultra-long ranging and ultra-wide FOV is expected to bring new opportunities for in vivo biomedical applications. PMID:27896012

  6. In vivo wide-field multispectral scanning laser ophthalmoscopy–optical coherence tomography mouse retinal imager: longitudinal imaging of ganglion cells, microglia, and Müller glia, and mapping of the mouse retinal and choroidal vasculature

    PubMed Central

    Zhang, Pengfei; Zam, Azhar; Jian, Yifan; Wang, Xinlei; Li, Yuanpei; Lam, Kit S.; Burns, Marie E.; Sarunic, Marinko V.; Pugh, Edward N.; Zawadzki, Robert J.

    2015-01-01

    Abstract. Scanning laser ophthalmoscopy (SLO) and optical coherence tomography (OCT) provide complementary views of the retina, with the former collecting fluorescence data with good lateral but relatively low-axial resolution, and the latter collecting label-free backscattering data with comparable lateral but much higher axial resolution. To take maximal advantage of the information of both modalities in mouse retinal imaging, we have constructed a compact, four-channel, wide-field (∼50  deg) system that simultaneously acquires and automatically coregisters three channels of confocal SLO and Fourier domain OCT data. The scanner control system allows “zoomed” imaging of a region of interest identified in a wide-field image, providing efficient digital sampling and localization of cellular resolution features in longitudinal imaging of individual mice. The SLO is equipped with a “flip-in” spectrometer that enables spectral “fingerprinting” of fluorochromes. Segmentation of retina layers and en face display facilitate spatial comparison of OCT data with SLO fluorescence patterns. We demonstrate that the system can be used to image an individual retinal ganglion cell over many months, to simultaneously image microglia and Müller glia expressing different fluorochromes, to characterize the distinctive spatial distributions and clearance times of circulating fluorochromes with different molecular sizes, and to produce unequivocal images of the heretofore uncharacterized mouse choroidal vasculature. PMID:26677070

  7. WIDE-FIELD ASTRONOMICAL MULTISCALE CAMERAS

    SciTech Connect

    Marks, Daniel L.; Brady, David J.

    2013-05-15

    In order to produce sufficiently low aberrations with a large aperture, telescopes have a limited field of view. Because of this narrow field, large areas of the sky at a given time are unobserved. We propose several telescopes based on monocentric reflective, catadioptric, and refractive objectives that may be scaled to wide fields of view and achieve 1.''1 resolution, which in most locations is the practical seeing limit of the atmosphere. The reflective and Schmidt catadioptric objectives have relatively simple configurations and enable large fields to be captured at the expense of the obscuration of the mirror by secondary optics, a defect that may be managed by image plane design. The refractive telescope design does not have an obscuration but the objective has substantial bulk. The refractive design is a 38 gigapixel camera which consists of a single monocentric objective and 4272 microcameras. Monocentric multiscale telescopes, with their wide fields of view, may observe phenomena that might otherwise be unnoticed, such as supernovae, glint from orbital space debris, and near-earth objects.

  8. Imaging spectrometer wide field catadioptric design

    DOEpatents

    Chrisp; Michael P.

    2008-08-19

    A wide field catadioptric imaging spectrometer with an immersive diffraction grating that compensates optical distortions. The catadioptric design has zero Petzval field curvature. The imaging spectrometer comprises an entrance slit for transmitting light, a system with a catadioptric lens and a dioptric lens for receiving the light and directing the light, an immersion grating, and a detector array. The entrance slit, the system for receiving the light, the immersion grating, and the detector array are positioned wherein the entrance slit transmits light to the system for receiving the light and the system for receiving the light directs the light to the immersion grating and the immersion grating receives the light and directs the light through the system for receiving the light to the detector array.

  9. Wide-field Infrared Survey Explorer

    NASA Technical Reports Server (NTRS)

    Padgett, Deborah

    2012-01-01

    We present WISE (Wide-field Infrared Survey Explorer) mid-infrared photometry of young stellar object candidates in the Canis Majoris clouds at a distance of 1 kpc. WISE has identified 682 objects with apparent 12 and 22 micron excess emission in a 7 deg x 10 deg field around the CMa Rl cloud . While a substantial fraction of these candidates are likely galaxies, AGB stars, and artifacts from confusion along the galactic plane, others are part of a spectacular cluster of YSOs imaged by WISE along a dark filament in the R1 cloud. Palomar Double Spectrograph observations of several sources in this cluster confirm their identity as young A and B stars with strong emission lines. In this contribution, we plot the optical -mid-infrared spectral energy distribution for the WISE YSO candidates and discuss potential contaminants to the sample . The data demonstrate the utility of WISE in performing wide-area surveys for young stellar objects.

  10. Wide-Field Detected Fourier Transform CARS Microscopy

    PubMed Central

    Duarte, Alex Soares; Schnedermann, Christoph; Kukura, Philipp

    2016-01-01

    We present a wide-field imaging implementation of Fourier transform coherent anti-Stokes Raman scattering (wide-field detected FT-CARS) microscopy capable of acquiring high-contrast label-free but chemically specific images over the full vibrational ‘fingerprint’ region, suitable for a large field of view. Rapid resonant mechanical scanning of the illumination beam coupled with highly sensitive, camera-based detection of the CARS signal allows for fast and direct hyperspectral wide-field image acquisition, while minimizing sample damage. Intrinsic to FT-CARS microscopy, the ability to control the range of time-delays between pump and probe pulses allows for fine tuning of spectral resolution, bandwidth and imaging speed while maintaining full duty cycle. We outline the basic principles of wide-field detected FT-CARS microscopy and demonstrate how it can be used as a sensitive optical probe for chemically specific Raman imaging. PMID:27881844

  11. Wide-Field Detected Fourier Transform CARS Microscopy

    NASA Astrophysics Data System (ADS)

    Duarte, Alex Soares; Schnedermann, Christoph; Kukura, Philipp

    2016-11-01

    We present a wide-field imaging implementation of Fourier transform coherent anti-Stokes Raman scattering (wide-field detected FT-CARS) microscopy capable of acquiring high-contrast label-free but chemically specific images over the full vibrational ‘fingerprint’ region, suitable for a large field of view. Rapid resonant mechanical scanning of the illumination beam coupled with highly sensitive, camera-based detection of the CARS signal allows for fast and direct hyperspectral wide-field image acquisition, while minimizing sample damage. Intrinsic to FT-CARS microscopy, the ability to control the range of time-delays between pump and probe pulses allows for fine tuning of spectral resolution, bandwidth and imaging speed while maintaining full duty cycle. We outline the basic principles of wide-field detected FT-CARS microscopy and demonstrate how it can be used as a sensitive optical probe for chemically specific Raman imaging.

  12. Wide field-of-view bifocal eyeglasses

    NASA Astrophysics Data System (ADS)

    Barbero, Sergio; Rubinstein, Jacob

    2015-09-01

    When vision is affected simultaneously by presbyopia and myopia or hyperopia, a solution based on eyeglasses implies a surface with either segmented focal regions (e.g. bifocal lenses) or a progressive addition profile (PALs). However, both options have the drawback of reducing the field-of-view for each power position, which restricts the natural eye-head movements of the wearer. To avoid this serious limitation we propose a new solution which is essentially a bifocal power-adjustable optical design ensuring a wide field-of-view for every viewing distance. The optical system is based on the Alvarez principle. Spherical refraction correction is considered for different eccentric gaze directions covering a field-of-view range up to 45degrees. Eye movements during convergence for near objects are included. We designed three bifocal systems. The first one provides 3 D for far vision (myopic eye) and -1 D for near vision (+2 D Addition). The second one provides a +3 D addition with 3 D for far vision. Finally the last system is an example of reading glasses with +1 D power Addition.

  13. Stereoscopic wide field of view imaging system

    NASA Technical Reports Server (NTRS)

    Prechtl, Eric F. (Inventor); Sedwick, Raymond J. (Inventor); Jonas, Eric M. (Inventor)

    2011-01-01

    A stereoscopic imaging system incorporates a plurality of imaging devices or cameras to generate a high resolution, wide field of view image database from which images can be combined in real time to provide wide field of view or panoramic or omni-directional still or video images.

  14. Filters for HST Wide Field Camera 3

    NASA Astrophysics Data System (ADS)

    Baggett, S.; Brown, T.; Boucarut, R.; Figer, D.; Hartig, G.; Kimble, R.; MacKenty, J.; Robberto, M.; Telfer, R.; Kim-Quijano, J.; Quijada, M.; Allen, G.; Arsenovic, P.; Hilbert, B.; Lupie, O.; Townsend, J.

    2006-06-01

    Wide-Field Camera 3 (WFC3) has been built for installation on the Hubble Space Telescope (HST) during the next servicing mission. The WFC3 instrument consists of both a UVIS and an IR channel, each with its own complement of filters. On the UVIS side, a selectable optical filter assembly (SOFA) contains a set of 12 wheels that house 48 elements (42 full-frame filters, 5 quadrant filters, and 1 UV grism). The IR channel has one filter wheel which houses 17 elements (15 filters and 2 grisms). While the majority of UVIS filters exhibited excellent performance during ground testing, a subset of filters showed filter ghosting; improved replacements for these filters have been procured and installed. No filter ghosting was found in any of the IR filters; however, the new IR detector for WFC3 will have significantly more response blueward of 800 nm than the original detector, requiring that two filters originally constructed on a fused silica substrate be remade to block any visible light transmission. This paper summarizes the characterization of the final complement of the WFC3 UVIS and IR filters, highlighting improvements in the replacement filters and the projected benefit to science observations.

  15. The wide field/planetary camera

    NASA Technical Reports Server (NTRS)

    Westphal, J. A.; Baum, W. A.; Code, A. D.; Currie, D. G.; Danielson, G. E.; Gunn, J. E.; Kelsall, T. F.; Kristian, J. A.; Lynds, C. R.; Seidelmann, P. K.

    1982-01-01

    A wide site of potential astronomical and solar system scientific studies using the wide field planetary camera on space telescope are described. The expected performance of the camera as it approaches final assembly and testing is also detailed.

  16. Invited Article: First Flight in Space of a Wide-field-of-view Soft X-Ray Imager Using Lobster-Eye Optics: Instrument Description and Initial Flight Results

    NASA Technical Reports Server (NTRS)

    Collier, Michael; Porter, F. Scott; Sibeck, David G.; Carter, Jenny A.; Chiao, Meng P.; Chomay, Dennis J.; Cravens, Thomas E.; Galeazzi, Massiniliano; Keller, John; Koutroumpa, Dimitra

    2015-01-01

    We describe the development, launch into space, and initial results from a prototype wide eld-of-view (FOV) soft X-ray imager that employs Lobster-eye optics and targets heliophysics, planetary, and astrophysics science. The Sheath Transport Observer for the Redistribution of Mass (STORM) is the rst instrument using this type of optics launched into space and provides proof-of-concept for future ight instruments capable of imaging structures such as the terrestrial cusp, the entire dayside magnetosheath from outside the magnetosphere, comets, the moon, and the solar wind interaction with planetary bodies like Venus and Mars.

  17. Invited Article: First Flight in Space of a Wide-Field-of-View Soft X-Ray Imager Using Lobster-Eye Optics: Instrument Description and Initial Flight Results

    NASA Technical Reports Server (NTRS)

    Collier, Michael R.; Porter, Frederick S.; Sibeck, David G.; Carter, Jenny A.; Chiao, Meng P.; Chornay, Dennis J.; Cravens, Thomas E.; Galeazzi, Massimiliano; Keller, John W.; Koutroumpa, Dimitra; Kujawski, Joseph; Kuntz, Kip; Read, Andy M.; Robertson, Ina P.; Sembay, Steve; Snowden, Steven; Thomas, Nicholas; Uprety, Youaraj; Walsh, Brian M.

    2015-01-01

    We describe the development, launch into space, and initial results from a prototype wide eld-of-view (FOV) soft X-ray imager that employs Lobster-eye optics and targets heliophysics, planetary, and astrophysics science. The Sheath Transport Observer for the Redistribution of Mass (STORM) is the rst instrument using this type of optics launched into space and provides proof-of-concept for future ight instruments capable of imaging structures such as the terrestrial cusp, the entire dayside magnetosheath from outside the magnetosphere, comets, the moon, and the solar wind interaction with planetary bodies like Venus and Mars.

  18. Fiber Optics: A Bright Future.

    ERIC Educational Resources Information Center

    Rice, James, Jr.

    1980-01-01

    Presents an overview of the impact of fiber optics on telecommunications and its application to information processing and library services, including information retrieval, news services, remote transmission of library services, and library networking. (RAA)

  19. Sensitivity analysis of a wide-field telescope

    NASA Astrophysics Data System (ADS)

    Lim, Juhee; Lee, Sangon; Moon, Il Kweon; Yang, Ho-Soon; Lee, Jong Ung; Choi, Young-Jun; Park, Jang-Hyun; Jin, Ho

    2013-07-01

    We are developing three ground-based wide-field telescopes. A wide-field Cassegrain telescope consists of two hyperbolic mirrors, aberration correctors and a field flattener for a 2-degree field of view. The diameters of the primary mirror and the secondary mirror are 500 mm and 200 mm, respectively. Corrective optics combined with four lenses, a filter and a window are also considered. For the imaging detection device, we use a charge coupled device (CCD) which has a 4096 × 4096 array with a 9-µm2 pixel size. One of the requirements is that the image motion limit of the opto-mechanical structure be less than 1 pixel size of the CCD on the image plane. To meet this requirement, we carried out an optical design evaluation and a misalignment analysis. Line-of-sight sensitivity equations are obtained from the rigid-body rotation in three directions and the rigid-body translation in three directions. These equations express the image motions at the image plane in terms of the independent motions of the optical components. We conducted a response simulation to evaluate the finite element method models under static load conditions, and the result is represented by the static response function. We show that the wide-field telescope system is stiff and stable enough to be supported and operated during its operating time.

  20. Optics for future solar system exploration

    NASA Technical Reports Server (NTRS)

    Norris, D. D.; Vescelus, F. E.; Wellman, J. B.

    1980-01-01

    The optics technology necessary for future solar system exploration is discussed. To satisfy the various mission objectives, optical components need to be of low weight, provide adequate spatial resolution and mapping coverage, provide necessary spectral resolution, provide means to perform adaptable mapping spectrometry, operate under low light levels, provide color images of high fidelity and operate under high temperatures. Future near-infrared mapping spectrometers are examined, and the use of focal-plane detectors to improve their sensitivity is discussed.

  1. Wide field imaging problems in radio astronomy

    NASA Astrophysics Data System (ADS)

    Cornwell, T. J.; Golap, K.; Bhatnagar, S.

    2005-03-01

    The new generation of synthesis radio telescopes now being proposed, designed, and constructed face substantial problems in making images over wide fields of view. Such observations are required either to achieve the full sensitivity limit in crowded fields or for surveys. The Square Kilometre Array (SKA Consortium, Tech. Rep., 2004), now being developed by an international consortium of 15 countries, will require advances well beyond the current state of the art. We review the theory of synthesis radio telescopes for large fields of view. We describe a new algorithm, W projection, for correcting the non-coplanar baselines aberration. This algorithm has improved performance over those previously used (typically an order of magnitude in speed). Despite the advent of W projection, the computing hardware required for SKA wide field imaging is estimated to cost up to $500M (2015 dollars). This is about half the target cost of the SKA. Reconfigurable computing is one way in which the costs can be decreased dramatically.

  2. Developing Wide-Field Spatio-Spectral Interferometry for Far-Infrared Space Applications

    NASA Technical Reports Server (NTRS)

    Leisawitz, David; Bolcar, Matthew R.; Lyon, Richard G.; Maher, Stephen F.; Memarsadeghi, Nargess; Rinehart, Stephen A.; Sinukoff, Evan J.

    2012-01-01

    Interferometry is an affordable way to bring the benefits of high resolution to space far-IR astrophysics. We summarize an ongoing effort to develop and learn the practical limitations of an interferometric technique that will enable the acquisition of high-resolution far-IR integral field spectroscopic data with a single instrument in a future space-based interferometer. This technique was central to the Space Infrared Interferometric Telescope (SPIRIT) and Submillimeter Probe of the Evolution of Cosmic Structure (SPECS) space mission design concepts, and it will first be used on the Balloon Experimental Twin Telescope for Infrared Interferometry (BETTII). Our experimental approach combines data from a laboratory optical interferometer (the Wide-field Imaging Interferometry Testbed, WIIT), computational optical system modeling, and spatio-spectral synthesis algorithm development. We summarize recent experimental results and future plans.

  3. The Wide-Field Infrared Explorer

    NASA Technical Reports Server (NTRS)

    Schember, Helene; Hacking, Perry

    1993-01-01

    More than 30% of current star formation is taking place ingalaxies known as starburst galaxies. Do starburst galaxies play a central role in the evolution of all galaxies, and can they lead us to the birth of galaxies and the source of quasars? We have proposed to build the Wide Field Infrared Explorer (WIRE), capable of detecting typical starburst galaxies at a redshift of 0.5, ultraluminous infrared galaxies behond a redshift of 2, and luminous protogalaxies beyond a redshift of 5.

  4. Wide-field fluorescence lifetime imaging of cancer

    PubMed Central

    McGinty, James; Galletly, Neil P.; Dunsby, Chris; Munro, Ian; Elson, Daniel S.; Requejo-Isidro, Jose; Cohen, Patrizia; Ahmad, Raida; Forsyth, Amanda; Thillainayagam, Andrew V.; Neil, Mark A. A.; French, Paul M. W.; Stamp, Gordon W

    2010-01-01

    Optical imaging of tissue autofluorescence has the potential to provide rapid label-free screening and detection of surface tumors for clinical applications, including when combined with endoscopy. Quantitative imaging of intensity-based contrast is notoriously difficult and spectrally resolved imaging does not always provide sufficient contrast. We demonstrate that fluorescence lifetime imaging (FLIM) applied to intrinsic tissue autofluorescence can directly contrast a range of surface tissue tumors, including in gastrointestinal tissues, using compact, clinically deployable instrumentation achieving wide-field fluorescence lifetime images of unprecedented clarity. Statistically significant contrast is observed between cancerous and healthy colon tissue for FLIM with excitation at 355 nm. To illustrate the clinical potential, wide-field fluorescence lifetime images of unstained ex vivo tissue have been acquired at near video rate, which is an important step towards real-time FLIM for diagnostic and interoperative imaging, including for screening and image-guided biopsy applications. PMID:21258496

  5. The wide field imager instrument for Athena

    NASA Astrophysics Data System (ADS)

    Meidinger, Norbert; Nandra, Kirpal; Plattner, Markus; Porro, Matteo; Rau, Arne; Santangelo, Andrea E.; Tenzer, Chris; Wilms, Jörn

    2014-07-01

    The "Hot and Energetic Universe" has been selected as the science theme for ESA's L2 mission, scheduled for launch in 2028. The proposed Athena X-ray observatory provides the necessary capabilities to achieve the ambitious goals of the science theme. The X-ray mirrors are based on silicon pore optics technology and will have a 12 m focal length. Two complementary camera systems are foreseen which can be moved in and out of the focal plane by an interchange mechanism. These instruments are the actively shielded micro-calorimeter spectrometer X-IFU and the Wide Field Imager (WFI). The WFI will combine an unprecedented survey power through its large field of view of 40 arcmin with a high countrate capability (approx. 1 Crab). It permits a state-of-the-art energy resolution in the energy band of 0.1 keV to 15 keV during the entire mission lifetime (e.g. FWHM <= 150 eV at 6 keV). This performance is accomplished by a set of DEPFET active pixel sensor matrices with a pixel size matching the angular resolution of 5 arcsec (on-axis) of the mirror system. Each DEPFET pixel is a combined detector-amplifier structure with a MOSFET integrated onto a fully depleted 450 micron thick silicon bulk. The signal electrons generated by an X-ray photon are collected in a so-called internal gate below the transistor channel. The resulting change of the conductivity of the transistor channel is proportional to the number of electrons and thus a measure for the photon energy. DEPFETs have already been developed for the "Mercury Imaging X-ray Spectrometer" on-board of ESA's BepiColombo mission. For Athena we develop enhanced sensors with integrated electronic shutter and an additional analog storage area in each pixel. These features improve the peak-to-background ratio of the spectra and minimize dead time. The sensor will be read out with a new, fast, low-noise multi-channel analog signal processor with integrated sequencer and serial analog output. The architecture of sensor and readout

  6. The wide field imager instrument for Athena

    NASA Astrophysics Data System (ADS)

    Meidinger, Norbert; Eder, Josef; Eraerds, Tanja; Nandra, Kirpal; Pietschner, Daniel; Plattner, Markus; Rau, Arne; Strecker, Rafael

    2016-07-01

    The WFI (Wide Field Imager) instrument is planned to be one of two complementary focal plane cameras on ESA's next X-ray observatory Athena. It combines unprecedented survey power through its large field of view of 40 amin x 40 amin together with excellent count rate capability (>= 1 Crab). The energy resolution of the silicon sensor is state-of-the-art in the energy band of interest from 0.2 keV to 15 keV, e.g. the full width at half maximum of a line at 7 keV will be <= 170 eV until the end of the nominal mission phase. This performance is accomplished by using DEPFET active pixel sensors with a pixel size of 130 μm x 130 μm well suited to the on-axis angular resolution of 5 arcsec half energy width (HEW) of the mirror system. Each DEPFET pixel is a combined sensor-amplifier structure with a MOSFET integrated onto a fully depleted 450 μm thick silicon bulk. Two detectors are planned for the WFI instrument: A large-area detector comprising four sensors with a total of 1024 x 1024 pixels and a fast detector optimized for high count rate observations. This high count rate capable detector permits for bright point sources with an intensity of 1 Crab a throughput of more than 80% and a pile-up of less than 1%. The fast readout of the DEPFET pixel matrices is facilitated by an ASIC development, called VERITAS-2. Together with the Switcher-A, a control ASIC that allows for operation of the DEPFET in rolling shutter mode, these elements form the key components of the WFI detectors. The detectors are surrounded by a graded-Z shield, which has in particular the purpose to avoid fluorescence lines that would contribute to the instrument background. Together with ultra-thin coating of the sensor and particle identification by the detector itself, the particle induced background shall be minimized in order to achieve the scientific requirement of a total instrumental background value smaller than 5 x 10-3 cts/cm2/s/keV. Each detector has its dedicated detector electronics

  7. Future of gradient index optics

    NASA Astrophysics Data System (ADS)

    Hashizume, Hideki; Hamanaka, Kenjiro; Graham, Alan C., III; Zhu, X. Frank

    2001-11-01

    First developed over 30 years ago, gradient index lenses play an important role not only in telecommunications technology, but also in applications such as information interface and biomedical technology. Traditional manufacturing consists of doping a certain ion, A+ into the mother glass, drawing the glass into rods and then immersing the rods into s molten salt bath containing another certain ion B+. During a thermal ion exchange process, the original ion migrates out of the mother glass, and is replaced by the alternate ion, creating a refractive index variation. Current research is being conducted to improve the thermal ion exchange technology, and open new applications. This research includes extending working distances to greater than 100mm, decreasing the lens diameter, increasing the effective radius, and combining the technology with other technologies such as photolithographically etched masks to produce arrays of gradient index lenses. As a result of this ongoing research, the gradient index lens is expected to continue to be the enabling optical technology in the first decade of the new millennium and beyond.

  8. Wide Field Camera 3 Accommodations for HST Robotics Servicing Mission

    NASA Technical Reports Server (NTRS)

    Ginyard, Amani

    2005-01-01

    This slide presentation discusses the objectives of the Hubble Space Telescope (HST) Robotics Servicing and Deorbit Mission (HRSDM), reviews the Wide Field Camera 3 (WFC3), and also reviews the contamination accomodations for the WFC3. The objectives of the HRSDM are (1) to provide a disposal capability at the end of HST's useful life, (2) to upgrade the hardware by installing two new scientific instruments: replace the Corrective Optics Space Telescope Axial Replacement (COSTAR) with the Cosmic Origins Spectrograph (COS), and to replace the Wide Field/Planetary Camera-2 (WFPC2) with Wide Field Camera-3, and (3) Extend the Scientific life of HST for a minimum of 5 years after servicing. Included are slides showing the Hubble Robotic Vehicle (HRV) and slides describing what the HRV contains. There are also slides describing the WFC3. One of the mechanisms of the WFC3 is to serve partially as replacement gyroscopes for HST. There are also slides that discuss the contamination requirements for the Rate Sensor Units (RSUs), that are part of the Rate Gyroscope Assembly on the WFC3.

  9. Light concentrator of the wide field of view Cherenkov telescope

    NASA Astrophysics Data System (ADS)

    Yang, Rui; Sheng, Xi Yi; Liao, Bo Lin

    2016-10-01

    The Wide Field of View Cherenkov Telescope (WFCT) is mainly constituted by optical reflector and focal-plane photomultiplier (PMT) array camera. In order to avoid loss of Cherenkov signal resulting from the dead area between circular PMT tubes and invalid fringe of each PMT, the light concentrator used as front window of PMT is considered to improve detective efficiency. Basing on the edge-ray principle and features of WFCT, several light concentrators are designed and simulated with ZEMAX. The result shows that the hollow hexahedral compound parabolic concentrator (hex-CPC) has good performance in collecting light. Moreover, the samples of the hollow hexahedral CPC have been manufactured and tested.

  10. PSF modelling for very wide-field CCD astronomy

    NASA Astrophysics Data System (ADS)

    Piotrowski, L. W.; Batsch, T.; Czyrkowski, H.; Cwiok, M.; Dabrowski, R.; Kasprowicz, G.; Majcher, A.; Majczyna, A.; Malek, K.; Mankiewicz, L.; Nawrocki, K.; Opiela, R.; Siudek, M.; Sokolowski, M.; Wawrzaszek, R.; Wrochna, G.; Zaremba, M.; Żarnecki, A. F.

    2013-03-01

    Context. One of the possible approaches to detecting optical counterparts of GRBs requires monitoring large parts of the sky. This idea has gained some instrumental support in recent years, such as with the "Pi of the Sky" project. The broad sky coverage of the "Pi of the Sky" apparatus results from using cameras with wide-angle lenses (20° × 20° field of view). Optics of this kind introduce significant deformations of the point spread function (PSF), increasing with the distance from the frame centre. A deformed PSF results in additional uncertainties in data analysis. Aims: Our aim was to create a model describing highly deformed PSF in optical astronomy, allowing uncertainties caused by image deformations to be reduced. Methods: Detailed laboratory measurements of PSF, pixel sensitivity, and pixel response functions were performed. These data were used to create an effective high quality polynomial model of the PSF. Finally, tuning the model and tests in applications to the real sky data were performed. Results: We have developed a PSF model that accurately describes even very deformed stars in our wide-field experiment. The model is suitable for use in any other experiment with similar image deformation, with a simple tuning of its parameters. Applying this model to astrometric procedures results in a significant improvement over standard methods, while basic photometry precision performed with the model is comparable to the results of an optimised aperture algorithm. Additionally, the model was used to search for a weak signal - namely a possible gamma ray burst optical precursor - showing very promising results. Conclusions: Precise modelling of the PSF function significantly improves the astrometric precision and enhances the discovery potential of a wide-field system with lens optics.

  11. Wide-field in vivo oral OCT imaging

    PubMed Central

    Lee, Anthony M. D.; Cahill, Lucas; Liu, Kelly; MacAulay, Calum; Poh, Catherine; Lane, Pierre

    2015-01-01

    We have built a polarization-sensitive swept source Optical Coherence Tomography (OCT) instrument capable of wide-field in vivo imaging in the oral cavity. This instrument uses a hand-held side-looking fiber-optic rotary pullback catheter that can cover two dimensional tissue imaging fields approximately 2.5 mm wide by up to 90 mm length in a single image acquisition. The catheter spins at 100 Hz with pullback speeds up to 15 mm/s allowing imaging of areas up to 225 mm2 field-of-view in seconds. A catheter sheath and two optional catheter sheath holders have been designed to allow imaging at all locations within the oral cavity. Image quality of 2-dimensional image slices through the data can be greatly enhanced by averaging over the orthogonal dimension to reduce speckle. Initial in vivo imaging results reveal a wide-field view of features such as epithelial thickness and continuity of the basement membrane that may be useful in clinic for chair-side management of oral lesions. PMID:26203389

  12. Development of the Wide Field Grism Spectrograph 2

    NASA Astrophysics Data System (ADS)

    Uehara, Mariko; Nagashima, Chie; Sugitani, Koji; Watanabe, Makoto; Sato, Shuji; Nagata, Tetsuya; Tamura, Motohide; Ebizuka, Noboru; Pickles, Andrew J.; Hodapp, Klaus W.; Itoh, Yoichi; Nakano, Makoto; Ogura, Katsuo

    2004-09-01

    We have developed the Wide Field Grism Spectrograph 2 (WFGS2) for the f/10 focus of the University of Hawaii 2.2 m telescope (UH88). This instrument provides slit-less, wide-field spectroscopy as well as imaging and long-slit spectroscopy. Two CCD cameras of UH88, Tektronix 2k x 2k and OPTIC 4k x 4k, can be used as a detector. The spectral coverage is 380 - 970 nm, and the field of view is 11'.5 x 11'.5 with a pixel scale of 0".34 (Tektronix) or 0".21 pixel-1 (OPTIC) in the imaging mode. WFGS2 has two replica grisms (R = 620 at 650 nm and R = 730 at 400 nm) and a Volume-Phase Holographic (VPH) grism (R = 2500 at 664 nm). The VPH grism enables intermediate-dispersion spectroscopy with this transmission system. Two long-slits with widths of 0".6 and 0".9 can be used. The Sloan Digital Sky Survey (g', r', i', z') and narrow-band (wide Hα, Hα, and [SII]+Li) filters are equipped. The first light observation was done in November 2003. We present the details of WFGS2, including the results of the first light observation.

  13. Origin and Future of Plasmonic Optical Tweezers

    PubMed Central

    Huang, Jer-Shing; Yang, Ya-Tang

    2015-01-01

    Plasmonic optical tweezers can overcome the diffraction limits of conventional optical tweezers and enable the trapping of nanoscale objects. Extension of the trapping and manipulation of nanoscale objects with nanometer position precision opens up unprecedented opportunities for applications in the fields of biology, chemistry and statistical and atomic physics. Potential applications include direct molecular manipulation, lab-on-a-chip applications for viruses and vesicles and the study of nanoscale transport. This paper reviews the recent research progress and development bottlenecks and provides an overview of possible future directions in this field. PMID:28347051

  14. Collimation of Fast Wide-Field Telescopes

    NASA Astrophysics Data System (ADS)

    McLeod, Brian A.

    1996-02-01

    In this paper, I present a simple technique for collimating the secondary mirror of fast focal ratio wide-field Cassegrain telescopes. This technique minimizes both coma and astigmatism across the field. Because astigmatism is nearly zero on-axis even in a misaligned system, it is necessary to make measurements off-axis. This technique is useful on telescopes corrected for off-axis coma such as Ritchey-Cretien designs and classical Cassegrains with refractive correctors. Proper alignment for astigmatism is especially important in the latter type of telescope where there is no astigmatism across the field in a properly aligned system. The tools required for collimation are a camera that can examine images at several locations at the edge of the field and a secondary mirror that can be controlled in five axes. Also presented are analytic expressions for the amount of field-dependent astigmatism due to miscollimation. The technique is robust enough to collimate telescopes with fixed astigmatism in the telescope primary. (SECTION: Astronomical Instrumentation)

  15. The IXO wide-field imager

    NASA Astrophysics Data System (ADS)

    Lechner, Peter; Aschauer, Florian; Bombelli, Luca; Fiorini, Carlo; Herrmann, Sven; Lauf, Thomas; Lutz, Gerhard; Majewski, Petra; Meuris, Aline; Porro, Matteo; Reiffers, Jonas; Richter, Rainer; Stefanescu, Alexander; Strüder, Lothar; Treis, Johannes; De Vita, Giulio

    2010-07-01

    The Wide Field Imager (WFI) of the International X-ray Observatory (IXO) is an X-ray imaging spectrometer based on a large monolithic DePFET (Depleted P-channel Field Effect Transistor) Active Pixel Sensor. Filling an area of 10 × 10 cm² with a format of 1024 × 1024 pixels it will cover a field of view of 18 arcmin. The pixel size of 100 × 100 μm² corresponds to a fivefold oversampling of the telescope's expected 5 arcsec point spread function. The WFI's basic DePFET structure combines the functionalities of sensor and integrated amplifier with nearly Fano-limited energy resolution and high efficiency from 100 eV to 15 keV. The development of dedicated control and amplifier ASICs allows for high frame rates up to 1 kHz and flexible readout modes. Results obtained with representative prototypes with a format of 256 × 256 pixels are presented.

  16. A Wide Field of View Plasma Spectrometer

    SciTech Connect

    Skoug, Ruth M.; Funsten, Herbert O.; Moebius, Eberhard; Harper, Ron W.; Kihara, Keith H.; Bower, Jonathan S.

    2016-07-01

    Here we present a fundamentally new type of space plasma spectrometer, the wide field of view plasma spectrometer, whose field of view is >1.25π ster using fewer resources than traditional methods. The enabling component is analogous to a pinhole camera with an electrostatic energy-angle filter at the image plane. Particle energy-per-charge is selected with a tunable bias voltage applied to the filter plate relative to the pinhole aperture plate. For a given bias voltage, charged particles from different directions are focused by different angles to different locations. Particles with appropriate locations and angles can transit the filter plate and are measured using a microchannel plate detector with a position-sensitive anode. Full energy and angle coverage are obtained using a single high-voltage power supply, resulting in considerable resource savings and allowing measurements at fast timescales. Lastly, we present laboratory prototype measurements and simulations demonstrating the instrument concept and discuss optimizations of the instrument design for application to space measurements.

  17. A wide field of view plasma spectrometer

    NASA Astrophysics Data System (ADS)

    Skoug, R. M.; Funsten, H. O.; Möbius, E.; Harper, R. W.; Kihara, K. H.; Bower, J. S.

    2016-07-01

    We present a fundamentally new type of space plasma spectrometer, the wide field of view plasma spectrometer, whose field of view is > 1.25π ster using fewer resources than traditional methods. The enabling component is analogous to a pinhole camera with an electrostatic energy-angle filter at the image plane. Particle energy-per-charge is selected with a tunable bias voltage applied to the filter plate relative to the pinhole aperture plate. For a given bias voltage, charged particles from different directions are focused by different angles to different locations. Particles with appropriate locations and angles can transit the filter plate and are measured using a microchannel plate detector with a position-sensitive anode. Full energy and angle coverage are obtained using a single high-voltage power supply, resulting in considerable resource savings and allowing measurements at fast timescales. We present laboratory prototype measurements and simulations demonstrating the instrument concept and discuss optimizations of the instrument design for application to space measurements.

  18. A Wide Field of View Plasma Spectrometer

    DOE PAGES

    Skoug, Ruth M.; Funsten, Herbert O.; Moebius, Eberhard; ...

    2016-07-01

    Here we present a fundamentally new type of space plasma spectrometer, the wide field of view plasma spectrometer, whose field of view is >1.25π ster using fewer resources than traditional methods. The enabling component is analogous to a pinhole camera with an electrostatic energy-angle filter at the image plane. Particle energy-per-charge is selected with a tunable bias voltage applied to the filter plate relative to the pinhole aperture plate. For a given bias voltage, charged particles from different directions are focused by different angles to different locations. Particles with appropriate locations and angles can transit the filter plate and aremore » measured using a microchannel plate detector with a position-sensitive anode. Full energy and angle coverage are obtained using a single high-voltage power supply, resulting in considerable resource savings and allowing measurements at fast timescales. Lastly, we present laboratory prototype measurements and simulations demonstrating the instrument concept and discuss optimizations of the instrument design for application to space measurements.« less

  19. Facility calibration unit of Hobby Eberly Telescope wide field upgrade

    NASA Astrophysics Data System (ADS)

    Lee, Hanshin; Hill, Gary J.; Vattiat, Brian L.; Smith, Michael P.; Haeuser, Marco

    2012-09-01

    The Hobby-Eberly Telescope (HET) Wide-Field Upgrade (WFU) will be equipped with new Facility Calibration Unit (FCU). The FCU is in support of VIRUS and the facility instruments and consists of the head and source box. The FCU head, connected to the source box through two liquid light guides, is attached to the bottom of the WFU Wide-Field Corrector (WFC) and can be deployed into the beam to inject calibration light through the WFC whenever calibration is needed. A set of Fresnel lenses is used in the FCU head to mimic the caustics of M1 as much as possible to re-produce the telescope’s focal plane illumination pattern. Various imaging/non-imaging optical components (e.g. Compound Parabolic Concentrators, cone reflectors, condenser lenses) are used for efficient coupling between different types of calibration lamps and light guides, covering wavelengths from 350nm to 1800nm. In addition, we developed an efficient and tunable Light-Emitting Diode (LED) based source and coupler for UV and Visible spectral flat field calibration. This paper presents the designs, prototypes, and as-built components / subsystems of the FCU.

  20. Two-mirror, three-reflection telescopes as candidates for sky surveys in ground and space applications. The MINITRUST: an active optics warping telescope for wide-field astronomy

    NASA Astrophysics Data System (ADS)

    Viotti, Roberto F.; La Padula, Cesare D.; Vignato, Agostino; Lemaitre, Gerard R.; Montiel, Pierre; Dohlen, Kjetil

    2002-12-01

    A concept based on a two-mirror, three-reflection telescope has been investigated. Its anastigmatism and flat fielded properties, the compactness and optical performances over 2-2.5 arc deg field of view, make this optical system of high interest for the development of much larger telescopes than with Schmidt designs. The 2MTRT concept is a potential candidate for sky surveys with 2-3 meter class telescopes and particularily well adapted for UV space surveys. Preliminary developments have been carried out with the construction of a 30-cm prototype on Amoretti's design, providing encouraging results. At present, a 45-cm 2MTRT prototype has been realized for ground based sky survey of NEOs, based on active optics (MINITRUST), in order to overcome the difficulty of obtaining three aspherical surfaces. The primary and tertiary lie on the same double vase substrate, and have a rest profile. The hyperbolization is carried out in situ by air depressure. The secondary, in a tulip form substrate, has been hyperbolized by elastic relaxation. The project is planned for operation in 2003.

  1. Wide-field surveys from the SNAP mission

    SciTech Connect

    agkim@lbl.gov

    2002-07-23

    The Supernova/Acceleration Probe (SNAP) is a proposed space-borne observatory that will survey the sky with a wide-field optical/NIR imager. The images produced by SNAP will have an unprecedented combination of depth, solid-angle, angular resolution, and temporal sampling. Two 7.5 square-degree fields will be observed every four days over 16 months to a magnitude depth of AB = 27.7 in each of nine filters. Co-adding images over all epochs will give an AB = 30.3 per filter. A 300 square-degree field will be surveyed with no repeat visits to AB = 28 per filter. The nine filters span 3500-17000 {angstrom}. Although the survey strategy is tailored for supernova and weak gravitational lensing observations, the resulting data supports a broad range of auxiliary science programs.

  2. Deployment of the Hobby-Eberly Telescope wide field upgrade

    NASA Astrophysics Data System (ADS)

    Hill, Gary J.; Drory, Niv; Good, John; Lee, Hanshin; Vattiat, Brian; Kriel, Herman; Bryant, Randy; Elliot, Linda; Landriau, Martin; Leck, Ron; Perry, David; Ramsey, Jason; Savage, Richard; Allen, Richard D.; Damm, George; DePoy, D. L.; Fowler, Jim; Gebhardt, Karl; Haeuser, Marco; MacQueen, Phillip; Marshall, J. L.; Martin, Jerry; Prochaska, Travis; Ramsey, Lawrence W.; Rheault, Jean-Philippe; Shetrone, Matthew; Schroeder Mrozinski, Emily; Tuttle, Sarah E.; Cornell, Mark E.; Booth, John; Moreira, Walter

    2014-07-01

    The Hobby-Eberly Telescope (HET) is an innovative large telescope located in West Texas at the McDonald Observatory. The HET operates with a fixed segmented primary and has a tracker, which moves the four-mirror optical corrector and prime focus instrument package to track the sidereal and non-sidereal motions of objects. A major upgrade of the HET is in progress that will substantially increase the pupil size to 10 meters (from 9.2 m) and the field of view to 22 arcminutes (from 4 arcminutes) by replacing the corrector, tracker, and prime focus instrument package. In addition to supporting existing instruments, and a new low resolution spectrograph, this wide field upgrade will feed a revolutionary new integral field spectrograph called VIRUS, in support of the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX§). The upgrade is being installed and this paper discusses the current status.

  3. Magnification with wide-field photometric surveys.

    NASA Astrophysics Data System (ADS)

    Garcia-Fernandez, M.; Sánchez, E.; Sevilla-Noarbe, I.

    2017-03-01

    A methodology to detect and measure magnification using the galaxy number count technique designed to be used at present and future photometric galaxy surveys is described. The method is tested with the N-body simulation MICE-GC showing that it allows to clearly detect magnification and showing agreement with the theory for sky areas of at least 110°^2.

  4. Long-range, wide-field swept-source optical coherence tomography with GPU accelerated digital lock-in Doppler vibrography for real-time, in vivo middle ear diagnostics

    PubMed Central

    MacDougall, Dan; Farrell, Joshua; Brown, Jeremy; Bance, Manohar; Adamson, Robert

    2016-01-01

    We present the design, implementation and validation of a swept-source optical coherence tomography (OCT) system for real-time imaging of the human middle ear in live patients. Our system consists of a highly phase-stable Vernier-tuned distributed Bragg-reflector laser along with a real-time processing engine implemented on a graphics processing unit. We use the system to demonstrate, for the first time in live subjects, real-time Doppler measurements of middle ear vibration in response to sound, video rate 2D B-mode imaging of the middle ear and 3D volumetric B-mode imaging. All measurements were performed non-invasively through the intact tympanic membrane demonstrating that the technology is readily translatable to the clinic. PMID:27896001

  5. Wide field of view infrared imaging system design

    NASA Astrophysics Data System (ADS)

    Rogala, Eric W.

    2004-08-01

    In the design of optical systems, simple straightforward requirements are often complicated by unusual and unique constraints. In this particular case a design mapping a 20° square field of view onto a CCD sensor is complicated by the requirement that the wide field of view must not vignette through a narrow-diameter, finite-length cylindrical aperture. Furthermore, the design must use off-the-shelf optics available from any major vendor. The imaging system is designed to operate in the near IR. The 20° square field of view must pass through a 20.32mm diameter, 40mm long cylindrical tube without vignetting. This constraint prohibits the use of a simple achromat whose back focal length would place the image within the cylindrical tube. Two design approaches are discussed, a Keplerian telescope with a field lens, and a reverse telephoto system. Matlab programs have been written that evaluate the first-order optical principles to arrive at a design solution space. Representative solutions are then evaluated in Zemax using the built-in lens catalog to select appropriate lenses. The results show the advantages and limitations of each particular design approach.

  6. Virtualized Optical Network (VON) for Future Internet and Applications

    NASA Astrophysics Data System (ADS)

    Jinno, Masahiko; Tsukishima, Yukio; Takara, Hidehiko; Kozicki, Bartlomiej; Sone, Yoshiaki; Sakano, Toshikazu

    A virtualized optical network (VON) is proposed as a key to implementing increased agility and flexibility into the future Internet and applications by providing any-to-any connectivity with the appropriate optical bandwidth at the appropriate time. The VON is enabled by introducing optical transparentization and optical fine granular grooming based on optical orthogonal frequency division multiplexing.

  7. Wide-field aberration corrector for spherical gossamer primary mirrors

    NASA Astrophysics Data System (ADS)

    Beach, David A.

    2000-10-01

    If gossamer primary mirrors were to be constructed in a spherical form, it would be possible to arrange a simple null- test in situ. However, spherical mirrors would require correction of the large amount of spherical aberration created in pupils that generally will be greater than 2 m diameter. The design requirement is for diffraction-limited performance over a useful angular field. The otherwise excellent wide- field design solutions of the classical Schmidt and Maksutov are inapplicable in gossamer structures because of the mass and size penalty of large refractive components. However, it is possible for this mode of correction to be achieved near the prime focus by means of pupil transfer optics that minify the large entrance pupil down to more acceptable dimensions. A problem with these solutions is constraint of field coverage due to pupil aberrations created by the large spherical aberration of the primary mirror. This leads the designer towards slower primaries and the penalty of larger, heavier structures. A solution is presented here for spherical primaries with speeds up to f/4. This is based on the 'KiwiStar' principle presented here in 1997, in which a large spherical catoptric is combined by pupil-transfer with a smaller spherical catadioptric to give well corrected wide field images of high speed. This system is well suited to correction at the prime focus of large spherical mirrors, and has only one relatively small weak aspheric surface to provide zonal correction, all other surfaces being spherical. An example is presented of a 4 m diameter, f/2.5 system that is diffraction-limited over the whole of a 0.25 degree field (43 mm diameter), for a bandpass of 486 - 850 nm.

  8. Wide-field-of-view (WFOV) night vision goggle

    NASA Astrophysics Data System (ADS)

    Isbell, Wayne; Estrera, Joseph P.

    2003-09-01

    The United States' armed forces continue to be presented with increased challenges in adverse operational environments with increasing risk and complexity - especially at night. To ensure continued operational success and battlefield superiority during darkness, our armed forces must be equipped with night vision (NV) systems providing increased situational awareness. Doing so will significantly enhance threat detection and engagement, as well as survivability, thus ensuring greater mission success. Northrop Grumman Electro-Optical Systems (EOS) continues to develop its Wide Field of View (WFOV) image intensification (I2) night vision system for ground forces. This system will provide a significant increase in visual coverage enabling US forces to continue "to own the night". Until now, NV systems have typically been limited to a 40-degree field of view (FOV), vertically and horizontally. This limited FOV reduces off-axis detection, restricts an individual soldier's recognition and engagement capabilities and hinders added peripheral vision. To counter this operational deficiency, EOS proposes the Wide Field of View (WFOV) night vision binocular. The WFOV system will have a 70-degree horizontal FOV, with a 55-degree vertical FOV. The increased FOV will result in increased situational awareness of soldiers' surrounding environment (including terrain, hazards, threat, etc) during normal night operations. It will also allow for rapid and safer movement, especially in MOUT operations. Additionally, the increased visual coverage of large areas will enable soldiers to detect and engage targets faster and with greater reliability. The WFOV binocular will significantly enhance survivability, threat detection and engagement, and hence, greater mission success rate.

  9. DMD-based programmable wide field spectrograph for Earth observation

    NASA Astrophysics Data System (ADS)

    Zamkotsian, Frédéric; Lanzoni, Patrick; Liotard, Arnaud; Viard, Thierry; Costes, Vincent; Hébert, Philippe-Jean

    2015-03-01

    In Earth Observation, Universe Observation and Planet Exploration, scientific return could be optimized in future missions using MOEMS devices. In Earth Observation, we propose an innovative reconfigurable instrument, a programmable wide-field spectrograph where both the FOV and the spectrum could be tailored thanks to a 2D micromirror array (MMA). For a linear 1D field of view (FOV), the principle is to use a MMA to select the wavelengths by acting on intensity. This component is placed in the focal plane of a first grating. On the MMA surface, the spatial dimension is along one side of the device and for each spatial point, its spectrum is displayed along the perpendicular direction: each spatial and spectral feature of the 1D FOV is then fully adjustable dynamically and/or programmable. A second stage with an identical grating recomposes the beam after wavelengths selection, leading to an output tailored 1D image. A mock-up has been designed, fabricated and tested. The micromirror array is the largest DMD in 2048 x 1080 mirrors format, with a pitch of 13.68μm. A synthetic linear FOV is generated and typical images have been recorded o at the output focal plane of the instrument. By tailoring the DMD, we could modify successfully each pixel of the input image: for example, it is possible to remove bright objects or, for each spatial pixel, modify the spectral signature. The very promising results obtained on the mock-up of the programmable wide-field spectrograph reveal the efficiency of this new instrument concept for Earth Observation.

  10. Design of wide-field imaging shack Hartmann testbed

    NASA Astrophysics Data System (ADS)

    Schatz, Lauren H.; Scott, R. Phillip; Bronson, Ryan S.; Sanchez, Lucas R. W.; Hart, Michael

    2016-09-01

    Standard adaptive optics systems measure the aberrations in the wavefronts of a beacon guide star caused by atmospheric turbulence, which limits the corrected field of view to the isoplanatic patch, the solid angle over which the optical aberration is roughly constant. For imaging systems that require a corrected field of view larger than the isoplanatic angle, a three-dimensional estimate of the aberration is required. We are developing a wide-field imaging Shack-Hartmann wavefront sensor (WFS) that will characterize turbulence over a large field of view tens of times the size of the isoplanatic angle. The technique will find application in horizontal and downward looking remote sensing scenarios where high resolution imaging through extended atmospheric turbulence is required. The laboratory prototype system consists of a scene generator, turbulence simulator, a Shack Hartman WFS arm, and an imaging arm. The system has a high intrinsic Strehl ratio, is telecentric, and diffraction limited. We present preliminary data and analysis from the system.

  11. Wide-field, high-resolution Fourier ptychographic microscopy

    PubMed Central

    Zheng, Guoan; Horstmeyer, Roarke; Yang, Changhuei

    2014-01-01

    In this article, we report an imaging method, termed Fourier ptychographic microscopy (FPM), which iteratively stitches together a number of variably illuminated, low-resolution intensity images in Fourier space to produce a wide-field, high-resolution complex sample image. By adopting a wavefront correction strategy, the FPM method can also correct for aberrations and digitally extend a microscope’s depth-of-focus beyond the physical limitations of its optics. As a demonstration, we built a microscope prototype with a resolution of 0.78 μm, a field-of-view of ~120 mm2, and a resolution-invariant depth-of-focus of 0.3 mm (characterized at 632 nm). Gigapixel colour images of histology slides verify FPM’s successful operation. The reported imaging procedure transforms the general challenge of high-throughput, high-resolution microscopy from one that is coupled to the physical limitations of the system’s optics to one that is solvable through computation. PMID:25243016

  12. The Wide-Field Imaging Interferometry Testbed: Progress and Plans

    NASA Technical Reports Server (NTRS)

    Rinehart, S. A.; Leisawitz, D.; Leviton, D.; Martino, A.; Maynard, W.; Mundy, L. G.; Zhang, X.

    2004-01-01

    We describe the technique of wide field mosaic imaging for optical/IR interferometers and present early experimental results from a laboratory instrument designed to validate, experiment with, and refine the technique. A conventional single-detector stellar interferometer operating with narrow bandwidth at center wavelength lambda is limited in its field of view to the primary beam of the individual telescope apertures, or approx. lambda/D(sub tel) radians, where is the telescope diameter. Such a field is too small for many applications; often one wishes to image extended sources. We are developing and testing a technique analogous to the mosaic method employed in millimeter and radio astronomy, but applicable to optical/IR Michelson interferometers, in which beam combination is done in the pupil plane. An N(sub pix) x N(sub pix) detector array placed in the image plane of the interferometer is used to record simultaneously the fringe patterns from many contiguous telescope fields, effectively multiplying the field size by N(sub pix)/2, where the factor 2 allows for Nyquist sampling. This mosaic imaging technique will be especially valuable for far IR and submillimeter interferometric space observatories such as the Space Infrared Interferometric Telescope (SPIRIT) and the Submillimeter Probe of the Evolution of Cosmic Structure (SPECS). SPIRIT and SPECS will be designed to provide sensitive, high angular resolution observations of fields several arcminutes in diameter, and views of the universe complementary to those provided by HST, NGST, and ALMA.

  13. Portable wide-field hand-held NIR scanner

    NASA Astrophysics Data System (ADS)

    Jung, Young-Jin; Roman, Manuela; Carrasquilla, Jennifer; Erickson, Sarah J.; Godavarty, Anuradha

    2013-03-01

    Near-infrared (NIR) optical imaging modality is one of the widely used medical imaging techniques for breast cancer imaging, functional brain mapping, and many other applications. However, conventional NIR imaging systems are bulky and expensive, thereby limiting their accelerated clinical translation. Herein a new compact (6 × 7 × 12 cm3), cost-effective, and wide-field NIR scanner has been developed towards contact as well as no-contact based real-time imaging in both reflectance and transmission mode. The scanner mainly consists of an NIR source light (between 700- 900 nm), an NIR sensitive CCD camera, and a custom-developed image acquisition and processing software to image an area of 12 cm2. Phantom experiments have been conducted to estimate the feasibility of diffuse optical imaging by using Indian-Ink as absorption-based contrast agents. As a result, the developed NIR system measured the light intensity change in absorption-contrasted target up to 4 cm depth under transillumination mode. Preliminary in-vivo studies demonstrated the feasibility of real-time monitoring of blood flow changes. Currently, extensive in-vivo studies are carried out using the ultra-portable NIR scanner in order to assess the potential of the imager towards breast imaging..

  14. Optical processing for future computer networks

    NASA Technical Reports Server (NTRS)

    Husain, A.; Haugen, P. R.; Hutcheson, L. D.; Warrior, J.; Murray, N.; Beatty, M.

    1986-01-01

    In the development of future data management systems, such as the NASA Space Station, a major problem represents the design and implementation of a high performance communication network which is self-correcting and repairing, flexible, and evolvable. To obtain the goal of designing such a network, it will be essential to incorporate distributed adaptive network control techniques. The present paper provides an outline of the functional and communication network requirements for the Space Station data management system. Attention is given to the mathematical representation of the operations being carried out to provide the required functionality at each layer of communication protocol on the model. The possible implementation of specific communication functions in optics is also considered.

  15. Focus Validation of the Wide-Field Infrared Explorer (WIRE)

    NASA Astrophysics Data System (ADS)

    Tansock, J.; Larsen, M.; Shumway, A.; Hacking, P.

    1998-09-01

    The Wide-Field Infrared Explorer (WIRE) is a small cryogenic spaceborne infrared telescope being readied for launch in September 1998 as the fifth of NASA's Small Explorers. WIRE illuminates two 128 x 128 Si:As Focal Plane Arrays (FPAs) produced by Boeing North American with a 30 cm diameter Ritchey Cretien diamond turned mirror system. A dichroic beam splitter and band-pass filter define two broad pass bands for a deep pointed survey to search for protogalaxies and to study the evolution of starburst galaxies. The Space Dynamics Laboratory at Utah State University (SDL/USU) developed and instrumented ground-based procedures to validate the focus of the WIRE Instrument. The procedures used point source data acquired during ground measurements obtained with a calibration source consisting of an illuminated pinhole near the focus of a cryogenically cooled collimator. Simulated point source measurements were obtained at multiple focus positions by translating the pinhole along the optical axis inside and outside the optimum focus of the collimator. The detector FPAs were moved to positions indicated by the test results. These focus positions were verified by subsequent cold tests using an independent cold collimator. The method and hardware used to obtain focus validation are described and results presented.

  16. The Receiver System for the Ooty Wide Field Array

    NASA Astrophysics Data System (ADS)

    Subrahmanya, C. R.; Prasad, P.; Girish, B. S.; Somashekar, R.; Manoharan, P. K.; Mittal, A. K.

    2017-03-01

    The legacy Ooty Radio Telescope (ORT) is being reconfigured as a 264-element synthesis telescope, called the Ooty Wide Field Array (OWFA). Its antenna elements are the contiguous 1.92 m sections of the parabolic cylinder. It will operate in a 38-MHz frequency band centred at 326.5 MHz and will be equipped with a digital receiver including a 264-element spectral correlator with a spectral resolution of 48 kHz. OWFA is designed to retain the benefits of equatorial mount, continuous 9-hour tracking ability and large collecting area of the legacy telescope and use of modern digital techniques to enhance the instantaneous field-of-view by more than an order of magnitude. OWFA has unique advantages for contemporary investigations related to large scale structure, transient events and space weather watch. In this paper, we describe the RF subsystems, digitizers and fibre optic communication of OWFA and highlight some specific aspects of the system relevant for the observations planned during the initial operation.

  17. Design of wide field and high resolution video lens

    NASA Astrophysics Data System (ADS)

    Xiao, Ze-xin; Zhan, Binzhou; Han, Haimei

    2009-11-01

    Online detecting is increasingly used in industrial process for the requirement of product quality improving. It is a trend that the "machine detecting" with "machine version + computer intelligence" as new method replaces traditional manual "eye observation". The essential of "machine detecting" is that image of object being collected with high resolution video lens on sensor panel of photoelectric (CCD ,CMOS) and detecting result being automatically gained by computer after the image saved and processed. "Machine detecting" is developing rapidly with the universal reception by enterprises because of its fine accurateness, high efficiency and the real time. Video lens is one of the important components of machine version system. Requirements of wide field and high resolution enlarged the complexity of video lens design. In this paper a design case used in visible light with field diameter Φ32mm, β=-0.25× and NA'=0.15. We give design parameters of the video lens which obtained with theoretically calculating and Oslo software optimization: MTF>0.3 in full field and 215lp/mm, distortion <0.05%.This lens has an excellent optic performance to match with 1.3 million pixels 1/2"CCD, and a high performance price ratio for being consist of only 7 single lens in the way of 5 units.

  18. Non-mydriatic, wide field, fundus video camera

    NASA Astrophysics Data System (ADS)

    Hoeher, Bernhard; Voigtmann, Peter; Michelson, Georg; Schmauss, Bernhard

    2014-02-01

    We describe a method we call "stripe field imaging" that is capable of capturing wide field color fundus videos and images of the human eye at pupil sizes of 2mm. This means that it can be used with a non-dilated pupil even with bright ambient light. We realized a mobile demonstrator to prove the method and we could acquire color fundus videos of subjects successfully. We designed the demonstrator as a low-cost device consisting of mass market components to show that there is no major additional technical outlay to realize the improvements we propose. The technical core idea of our method is breaking the rotational symmetry in the optical design that is given in many conventional fundus cameras. By this measure we could extend the possible field of view (FOV) at a pupil size of 2mm from a circular field with 20° in diameter to a square field with 68° by 18° in size. We acquired a fundus video while the subject was slightly touching and releasing the lid. The resulting video showed changes at vessels in the region of the papilla and a change of the paleness of the papilla.

  19. Infrared Testing of the Wide-field Infrared Survey Telescope Grism Using Computer Generated Holograms

    NASA Technical Reports Server (NTRS)

    Dominguez, Margaret Z.; Content, David A.; Gong, Qian; Griesmann, Ulf; Hagopian, John G.; Marx, Catherine T; Whipple, Arthur L.

    2017-01-01

    Infrared Computer Generated Holograms (CGHs) were designed, manufactured and used to measure the performance of the grism (grating prism) prototype which includes testing Diffractive Optical Elements (DOE). The grism in the Wide Field Infrared Survey Telescope (WFIRST) will allow the surveying of a large section of the sky to find bright galaxies.

  20. Wide-field strain imaging with preferentially aligned nitrogen-vacancy centers in polycrystalline diamond

    NASA Astrophysics Data System (ADS)

    Trusheim, Matthew E.; Englund, Dirk

    2016-12-01

    We report on wide-field optically detected magnetic resonance imaging of nitrogen-vacancy centers (NVs) in type IIa polycrystalline diamond. These studies reveal a heterogeneous crystalline environment that produces a varied density of NV centers, including preferential orientation within some individual crystal grains, but preserves long spin coherence times. Using the native NVs as nanoscale sensors, we introduce a three-dimensional strain imaging technique with high sensitivity (< {10}-5 Hz-1/2) and diffraction-limited resolution across a wide field of view.

  1. CCD photometry using a wide-field Newtonian telescope.

    NASA Astrophysics Data System (ADS)

    Menako, C. R.; Henson, G. D.; Castelaz, M. A.; Powell, H. D.

    1996-01-01

    The paper demonstrates the utility of a CCD electronic-imaging camera at the focus of a wide-field Newtonian telescope as an efficient system for astronomical photometry. The CCD camera coupled to the wide-field telescope images one square degree of the sky, allowing for simultaneous light flux measurement of multiple stars without instrument repositioning. Photometric data acquired from the variable star W UMa using this system is compared to published values.

  2. MEO and LEO space debris optical observations at Crimean Observatory: first experience and future perspectives.

    NASA Astrophysics Data System (ADS)

    Rumyantsev, Vasilij; Biryukov, Vadim; Agapov, Vladimir; Molotov, Igor

    The near Earth space observation group of Crimean Observatory is performing the regular op-tical monitoring of space debris at GEO region within framework of the International Scientific Optical Network (ISON). During last years we also paid attention to objects on lower orbits due to increasing interest to LEO and MEO regions caused by several catastrophic events happened in the recent past. Optical observations provide high quality information about position and physical properties of space debris at LEO and MEO so they can be considered as another source of data comple-mentary to traditional radar measurements. We will discuss our observations of fragments from Briz-M upper stage (object 28944) and Block-DM ullage motor (25054) explosions. Results of observation of USA-193 debris will be presented. Then we will focus on observations and some photometric properties of FengYun 1C debris as well as Cosmos 2251 and Iridium 33 fragments. Radar cross-section versus optical photometry will be compared. Moreover, estimates of orbital parameters as well as area-to-mass ratio for some observed objects will be given. Most of our observations which we discuss in the paper represent just the first attempt to investigate capabilities of our optical system to observe MEO and LEO objects. But these results are very promising and show good perspectives for the future. We will briefly describe future perspectives of our optical observations of space debris and other objects in MEO and LEO region after the new wide-field telescopes will be put into operation.

  3. Update on the Wide-field Infrared Survey Explorer (WISE)

    NASA Technical Reports Server (NTRS)

    Mainzer, Amanda K.; Eisenhardt, Peter; Wright, Edward L.; Liu, Feng-Chuan; Irace, William; Heinrichsen, Ingolf; Cutri, Roc; Duval, Valerie

    2006-01-01

    The Wide-field Infrared Survey Explorer (WISE), a NASA MIDEX mission, will survey the entire sky in four bands from 3.3 to 23 microns with a sensitivity 1000 times greater than the IRAS survey. The WISE survey will extend the Two Micron All Sky Survey into the thermal infrared and will provide an important catalog for the James Webb Space Telescope. Using 1024(sup 2) HgCdTe and Si:As arrays at 3.3, 4.7, 12 and 23 microns, WISE will find the most luminous galaxies in the universe, the closest stars to the Sun, and it will detect most of the main belt asteroids larger than 3 km. The single WISE instrument consists of a 40 cm diamond-turned aluminum afocal telescope, a two-stage solid hydrogen cryostat, a scan mirror mechanism, and reimaging optics giving 5 resolution (full-width-half-maximum). The use of dichroics and beamsplitters allows four color images of a 47' x47' field of view to be taken every 8.8 seconds, synchronized with the orbital motion to provide total sky coverage with overlap between revolutions. WISE will be placed into a Sun-synchronous polar orbit on a Delta 7320-10 launch vehicle. The WISE survey approach is simple and efficient. The three-axis-stabilized spacecraft rotates at a constant rate while the scan mirror freezes the telescope line of sight during each exposure. WISE has completed its mission Preliminary Design Review and its NASA Confirmation Review, and the project is awaiting confirmation from NASA to proceed to the Critical Design phase. Much of the payload hardware is now complete, and assembly of the payload will occur over the next year. WISE is scheduled to launch in late 2009; the project web site can be found at www.wise.ssl.berkeley.edu.

  4. PSF reconstruction for MUSE in wide field mode

    NASA Astrophysics Data System (ADS)

    Villecroze, R.; Fusco, Thierry; Bacon, Roland; Madec, Pierre-Yves

    2012-07-01

    The resolution of ground-based telescopes is dramatically limited by the atmospheric turbulence.. Adaptative optics (AO) is a real-time opto-mechanical approach which allows to correct for the turbulence effect and to reach the ultimate diffraction limit astronomical telescopes and their associated instrumentation. Nevertheless, the AO correction is never perfect especially when it has to deal with large Field of View (FoV). Hence, a posteriori image processing really improves the final estimation of astrophysical data. Such techniques require an accurate knowledge of the system response at any position in the FoV The purpose of this work is then the estimation of the AO response in the particular case of the MUSE [1] /GALACSI [2] instrument (a 3D mult-object spectrograph combined with a Laser-assisted wide field AO system which will be installed at the VLT in 2013). Using telemetry data coming from both AO Laser and natural guide stars, a Point Spread Function (PSF) is derived at any location of the FoV and for every wavelength of the MUSE spectrograph. This document presents the preliminary design of the MUSE WFM PSF reconstruction process. The various hypothesis and approximations are detailed and justified. A first description of the overall process is proposed. Some alternative strategies to improve the performance (in terms of computation time and storage) are described and have been implemented. Finally, after a validation of the proposed algorithm using end-to-end models, a performance analysis is conducted (with the help of a full end-to-end model). This performance analysis will help us to populate an exhaustive error budget table.

  5. The Wide Field Spectrograph (WiFeS)

    NASA Astrophysics Data System (ADS)

    Dopita, Michael; Hart, John; McGregor, Peter; Oates, Patrick; Bloxham, Gabe; Jones, Damien

    2007-08-01

    This paper describes the Wide Field Spectrograph (WiFeS) under construction at the Research School of Astronomy and Astrophysics (RSAA) of the Australian National University (ANU) for the ANU 2.3 m telescope at the Siding Spring Observatory. WiFeS is a powerful integral field, double-beam, concentric, image-slicing spectrograph designed to deliver excellent throughput, wavelength stability, spectrophotometric performance and superb image quality along with wide spectral coverage throughout the 320 950 nm wavelength region. It provides a 25×38 arcsec field with 0.5 arcsec sampling along each of twenty five 38×1 arcsec slitlets. The output format is optimized to match the 4096×4096 pixel CCD detectors in each of two cameras individually optimized for the blue and the red ends of the spectrum, respectively. A process of “interleaved nod-and-shuffle” will be applied to permit quantum noise-limited sky subtraction. Using VPH gratings, spectral resolutions of 3000 and 7000 are provided. The full spectral range is covered in a single exposure at R=3000, and in two exposures in the R=7000 mode. The use of transmissive coated optics, VPH gratings and optimized mirror coatings ensures a throughput (including telescope atmosphere and detector) >30% over a wide spectral range. The concentric image-slicer design ensures an excellent and uniform image quality across the full field. To maximize scientific return, the whole instrument is configured for remote observing, pipeline data reduction, and the accumulation of calibration image libraries.

  6. Texas Supernova Search: A Wide Field Search for Nearby SNe

    NASA Astrophysics Data System (ADS)

    Quimby, R. M.; Castro, F.; Gerardy, C. L.; Hoeflich, P.; Kannappan, S. J.; Mondol, P.; Sellers, M.; Wheeler, J. C.

    2005-12-01

    ROTSE-IIIb is one four robotic telescopes built by the University of Michigan to observe the prompt optical afterglows associated with gamma-ray bursts. At just 0.45m in diameter, it is the smallest research telescope at McDonald, but its 1.85 x 1.85 deg field of view and autonomous operation make it an excellent survey instrument for rare transient phenomena. We have been using ROTSE-IIIb for the past year to search for supernovae in nearby galaxy clusters such as the Virgo, Coma, and Ursa Major clusters. ROTSE-IIIb's wide field of view allows us to search the thousands of galaxies in these clusters, which cover hundreds of square degrees on the sky, in just a few tens of exposures. We can therefore observe all of these fields in a single night, and repeat the search every night. When we identify a new supernova candidate, we invoke our target of opportunity time on the neighboring 9.2m Hobby-Eberly Telescope (HET) the following night to obtain a spectrum. Because of the rolling search and the quick spectral turn-around possible with the HET, we are able to capture spectra of the earliest phases of the explosion. By combining this information with spectra taken at later epochs, we can construct a complete description of the explosion. Through this work we aim to better understand the physical conditions of supernova explosions, identify any systematic effects that may affect how Type Ia supernovae are calibrated as standard candles and used to probe cosmology, and also to better calibrate Type II supernovae as standard candles.

  7. Hybrid wide-field and scanning microscopy for high-speed 3D imaging.

    PubMed

    Duan, Yubo; Chen, Nanguang

    2015-11-15

    Wide-field optical microscopy is efficient and robust in biological imaging, but it lacks depth sectioning. In contrast, scanning microscopic techniques, such as confocal microscopy and multiphoton microscopy, have been successfully used for three-dimensional (3D) imaging with optical sectioning capability. However, these microscopic techniques are not very suitable for dynamic real-time imaging because they usually take a long time for temporal and spatial scanning. Here, a hybrid imaging technique combining wide-field microscopy and scanning microscopy is proposed to accelerate the image acquisition process while maintaining the 3D optical sectioning capability. The performance was demonstrated by proof-of-concept imaging experiments with fluorescent beads and zebrafish liver.

  8. A 4-meter wide field coronagraph space telescope for general astrophysics and exoplanet observations

    NASA Astrophysics Data System (ADS)

    Tenerelli, Domenick; Angel, Roger; Burge, Jim; Guyon, Olivier; Zabludoff, Ann; Belikov, Ruslan; Pluzhnik, Eugene; Egerman, Robert

    2010-07-01

    The Wide Field Coronagraph Telescope (WFCT) is a 4-meter space telescope for general astrophysics and exoplanet observations that meets the 2000 Decadal Committee requirements. This paper presents a design for a 4-m diameter, off-axis space telescope that offers high performance in both wide field and coronagraphic imaging modes. A 3.8 x 3.3-m unobstructed elliptical pupil is provided for direct coronagraphic imaging of exoplanets and a 4-m diameter pupil for wide-field imaging from far-ultraviolet (UV) to near-infrared (IR). The off-axis wide-field optics are all reflective and designed to deliver an average of 12 nm wavefront aberrations over a 6 x 24 arcminute field of view (FOV), therefore providing diffraction-limited images down to 300 nm wavelength and 15 mas images down to a wavelength limit set only by the mirror coatings. The coronagraph with phase-induced amplitude apodization (PIAA) provides diffraction suppression around a 360-degree field with high Strehl and sensitivity at the 1e-10 level to an inner working angle of 2 λ/D (or 50 mas at 500 nm wavelength). This paper focuses on the optical design that allows the above imaging features to be combined in single telescope, and gives a preliminary spacecraft design and costing, assuming a distant trailing orbit.

  9. Wide-field holography of Compact Array antennae at 1.4 GHz

    NASA Astrophysics Data System (ADS)

    Middelberg, E.; Voronkov, M.; Kesteven, M.; Cornwell, T.; Graves, G.

    2006-08-01

    It is not trivial to produce high-SNR images from radio interferometer data. In very deep integrations at low frequencies, strong radio sources well outside the primary beams cause sidelobes in the synthesized image, and limit its dynamic range. These sidelobes cannot be removed with cleaning and self-calibration techniques, and it becomes necessary to predict the effects of strong sources and to remove them from the data before an image is formed. We present results from recent holographic measurements of a subset of the antennae of the Australia Telescope Compact Array (ATCA) at 1.4 GHz. We have mapped in detail the far-field reception pattern of ATCA antennae to sources as far as 20 degrees away from the optical axis, using beacons of a geostationary satellite. We report the results from these observations and the improvements they yield for wide-field, deep radio interferometer observations. Future sensitive, low-frequency radio interferometers such as the xNTD and the SKA will need similar calibration techniques to reach their full potential.

  10. Automated classification of periodic variable stars detected by the wide-field infrared survey explorer

    SciTech Connect

    Masci, Frank J.; Grillmair, Carl J.; Cutri, Roc M.; Hoffman, Douglas I.

    2014-07-01

    We describe a methodology to classify periodic variable stars identified using photometric time-series measurements constructed from the Wide-field Infrared Survey Explorer (WISE) full-mission single-exposure Source Databases. This will assist in the future construction of a WISE Variable Source Database that assigns variables to specific science classes as constrained by the WISE observing cadence with statistically meaningful classification probabilities. We have analyzed the WISE light curves of 8273 variable stars identified in previous optical variability surveys (MACHO, GCVS, and ASAS) and show that Fourier decomposition techniques can be extended into the mid-IR to assist with their classification. Combined with other periodic light-curve features, this sample is then used to train a machine-learned classifier based on the random forest (RF) method. Consistent with previous classification studies of variable stars in general, the RF machine-learned classifier is superior to other methods in terms of accuracy, robustness against outliers, and relative immunity to features that carry little or redundant class information. For the three most common classes identified by WISE: Algols, RR Lyrae, and W Ursae Majoris type variables, we obtain classification efficiencies of 80.7%, 82.7%, and 84.5% respectively using cross-validation analyses, with 95% confidence intervals of approximately ±2%. These accuracies are achieved at purity (or reliability) levels of 88.5%, 96.2%, and 87.8% respectively, similar to that achieved in previous automated classification studies of periodic variable stars.

  11. Deepest Wide-Field Colour Image in the Southern Sky

    NASA Astrophysics Data System (ADS)

    2003-01-01

    " (HDF-N in the northern and HDF-S in the southern sky, cf. e.g. ESO PR Photo 35a/98 ), but the field-of-view is about 200 times larger. The present image displays about 50 times more galaxies than the HDF images, and therefore provides a more representative view of the universe . The WFI CDF-S image will now form a most useful basis for the very extensive and systematic census of the population of distant galaxies and quasars, allowing at once a detailed study of all evolutionary stages of the universe since it was about 2 billion years old . These investigations have started and are expected to provide information about the evolution of galaxies in unprecedented detail. They will offer insights into the history of star formation and how the internal structure of galaxies changes with time and, not least, throw light on how these two evolutionary aspects are interconnected. GALAXIES IN THE WFI IMAGE ESO PR Photo 02b/03 ESO PR Photo 02b/03 [Preview - JPEG: 488 x 400 pix - 112k] [Normal - JPEG: 896 x 800 pix - 1.0M] [Full-Res - JPEG: 2591 x 2313 pix - 8.6M] Caption : PR Photo 02b/03 contains a collection of twelve subfields from the full WFI Chandra Deep Field South (WFI CDF-S), centred on (pairs or groups of) galaxies. Each of the subfields measures 2.5 x 2.5 arcmin 2 (635 x 658 pix 2 ; 1 pixel = 0.238 arcsec). North is up and East is left. Technical information is available below. The WFI CDF-S colour image - of which the full field is shown in PR Photo 02a/03 - was constructed from all available observations in the optical B- ,V- and R-bands obtained under good conditions with the Wide Field Imager (WFI) on the 2.2-m MPG/ESO telescope at the ESO La Silla Observatory (Chile), and now stored in the ESO Science Data Archive. It is the "deepest" image ever taken with this instrument. It covers a sky field measuring 36 x 34 arcmin 2 , i.e., an area somewhat larger than that of the full moon. The observations were collected during a period of nearly four years, beginning in

  12. The Astronomical Potential of Wide-field Imaging from Space

    NASA Astrophysics Data System (ADS)

    Beckwith, S.

    2001-12-01

    Wide-field imaging is best done from space. Unrestricted by seeing and the limitations of an isoplanatic patch, it should be possible to construct space telescopes delivering very wide fields of diffraction-limited images with enormous information content per image. Among the science programs that will benefit are complete sky surveys to look for rare objects, staring observations to look for microlensing events, monitoring of star clusters to look for eclipses by extra-solar planets, regular surveys of large regions to search for time-variable phenomena, especially supernovae, and repeated observations of the ecliptic to identify ``killer asteroids" and other interlopers. This talk will discuss some of the science that could be enabled by wide-field imaging telescopes in space such as the SNAP satellite.

  13. IAU Working Group on Wide-Field Imaging.

    NASA Astrophysics Data System (ADS)

    MacGillivray, H. T.

    1991-01-01

    Contents: 1. Introduction - The IAU Working Group on Wide-Field Imaging (R. M. West). 2. Reports from the Sub-Sections of the Working Group - a. Sky surveys and patrols (R. M. West). b. Photographic techniques (D. F. Malin). c. Digitization techniques (H. T. MacGillivray). d. Archival and retrieval of wide-field data (B. Lasker). 3. Meeting of the Organising Committee (R. M. West). 4. Wide-field plate archives (M. Tsvetkov). 5. Reproduction of the Palomar Observatory Sky Surveys (R. J. Brucato). 6. Status of the St ScI scan-distribution program (B. Lasker). 7. Pixel addition - pushing Schmidt plates to B = 25 (M. R. S. Hawkins). 8. Photometry from Estar film (S. Phillipps, Q. Parker). 9. ASCHOT - Astrophysical Schmidt Orbital Telescope (H. Lorenz). 10. The Hitchhiker parallel CCD camera (J. Davies, M. Disney, S. Driver, I. Morgan, S. Phillipps).

  14. Ultra-Wide-Field Fluorescein Angiography in Microscopic Polyangiitis

    PubMed Central

    Philander, Shannon A.; Ter-Zakarian, Anna; Rao, Narsing A.; Rodger, Damien C.

    2016-01-01

    A 25-year-old Hispanic female presented with 5 months of dry eyes and 2 months of bilateral photophobia and decreased vision. On examination, she had bilateral anterior uveitis and mild disc edema of the left eye. A complete infectious and inflammatory work-up was positive for elevated antinuclear antibodies and p-ANCA, leading to a diagnosis of microscopic polyangiitis. One year after initial treatment and steroid taper, an ultra-wide-field fluorescein angiography revealed peripheral vasculitis, outside of the standard traditional field of view, leading to an increase in immunomodulatory therapy and illustrating the utility of wide-field angiography for managing patients with uveitis. PMID:27872779

  15. Telecom optical componentry: past, present, future

    NASA Astrophysics Data System (ADS)

    Eldada, Louay A.

    2001-10-01

    We review and contrast key technologies developed to address the optical components market for telecom applications. We first look at different material systems, compare their properties, and describe the functions achieved to date in each of them. The material systems reviewed include silica fiber, silica on silicon, silicon on insulator, silicon oxynitride, sol-gels, polymers, thin film dielectrics, lithium niobate, indium phosphide, gallium arsenide, magneto-optic materials, and birefringent crystals. We then look at the most commonly used classes of technology and present their pros & cons as well as the functions achieved to date in each. The technologies reviewed include passive, actuation, and active technologies. The passive technologies described include fused fibers, dispersion-compensating fiber, beam steering (e.g., AWG), Bragg gratings, diffraction gratings, holographic elements, thin film filters, photonic crystals, microrings, and birefringent elements. The actuation technologies include thermo-optics, electro-optics, acousto-optics, magneto-optics, liquid crystals, total internal reflection technologies (e.g., bubble technology), and mechanical actuation (e.g., moving fibers, MEMS). We finally describe active technologies including heterostructures, quantum wells, rare earth doping, Raman amplification, and semiconductor amplification. We also investigate the use of different material systems and technologies to achieve building block functions including lasers, amplifiers, detectors, modulators, polarization controllers, couplers, filters, switches, attenuators, non-reciprocal elements for isolators and circulators, wavelength converters, chromatic dispersion compensators, and polarization mode dispersion (PMD) compensators. Some of the technologies presented are established in the industry, others have recently been proven to be commercially viable, and some others are still under development in laboratories.

  16. The Future of X-Ray Optics

    NASA Technical Reports Server (NTRS)

    Weisskopf, Martin C.

    2013-01-01

    The most important next step is the development of X-ray optics comparable to (or better than) Chandra in angular resolution that far exceed Chandra s effective area. Use the long delay to establish an adequately funded, competitive technology program along the lines I have recommended. Don't be diverted from this objective, except for Explorer-class missions. Progress in X-ray optics, with emphasis on the angular resolution, is central to the paradigm-shifting discoveries and the contributions of X-ray astronomy to multiwavelength astrophysics over the past 51 years.

  17. Design Evolution of the Wide Field Infrared Survey Telescope Using Astrophysics Focused Telescope Assets (WFIRST-AFTA) and Lessons Learned

    NASA Technical Reports Server (NTRS)

    Peabody, Hume L.; Peters, Carlton V.; Rodriguez-Ruiz, Juan E.; McDonald, Carson S.; Content, David A.; Jackson, Clifton E.

    2015-01-01

    The design of the Wide Field Infrared Survey Telescope using Astrophysics Focused Telescope Assets (WFIRST-AFTA) continues to evolve as each design cycle is analyzed. In 2012, two Hubble sized (2.4 m diameter) telescopes were donated to NASA from elsewhere in the Federal Government. NASA began investigating potential uses for these telescopes and identified WFIRST as a mission to benefit from these assets. With an updated, deeper, and sharper field of view than previous design iterations with a smaller telescope, the optical designs of the WFIRST instruments were updated and the mechanical and thermal designs evolved around the new optical layout. Beginning with Design Cycle 3, significant analysis efforts yielded a design and model that could be evaluated for Structural-Thermal-Optical-Performance (STOP) purposes for the Wide Field Imager (WFI) and provided the basis for evaluating the high level observatory requirements. Development of the Cycle 3 thermal model provided some valuable analysis lessons learned and established best practices for future design cycles. However, the Cycle 3 design did include some major liens and evolving requirements which were addressed in the Cycle 4 Design. Some of the design changes are driven by requirements changes, while others are optimizations or solutions to liens from previous cycles. Again in Cycle 4, STOP analysis was performed and further insights into the overall design were gained leading to the Cycle 5 design effort currently underway. This paper seeks to capture the thermal design evolution, with focus on major design drivers, key decisions and their rationale, and lessons learned as the design evolved.

  18. Design Evolution of the Wide Field Infrared Survey Telescope using Astrophysics Focused Telescope Assets (WFIRST-AFTA) and Lessons Learned

    NASA Technical Reports Server (NTRS)

    Peabody, Hume; Peters, Carlton; Rodriguez, Juan; McDonald, Carson; Content, David A.; Jackson, Cliff

    2015-01-01

    The design of the Wide Field Infrared Survey Telescope using Astrophysics Focused Telescope Assets (WFIRST-AFTA) continues to evolve as each design cycle is analyzed. In 2012, two Hubble sized (2.4 m diameter) telescopes were donated to NASA from elsewhere in the Federal Government. NASA began investigating potential uses for these telescopes and identified WFIRST as a mission to benefit from these assets. With an updated, deeper, and sharper field of view than previous design iterations with a smaller telescope, the optical designs of the WFIRST instruments were updated and the mechanical and thermal designs evolved around the new optical layout. Beginning with Design Cycle 3, significant analysis efforts yielded a design and model that could be evaluated for Structural-Thermal-Optical-Performance (STOP) purposes for the Wide Field Imager (WFI) and provided the basis for evaluating the high level observatory requirements. Development of the Cycle 3 thermal model provided some valuable analysis lessons learned and established best practices for future design cycles. However, the Cycle 3 design did include some major liens and evolving requirements which were addressed in the Cycle 4 Design. Some of the design changes are driven by requirements changes, while others are optimizations or solutions to liens from previous cycles. Again in Cycle 4, STOP analysis was performed and further insights into the overall design were gained leading to the Cycle 5 design effort currently underway. This paper seeks to capture the thermal design evolution, with focus on major design drivers, key decisions and their rationale, and lessons learned as the design evolved.

  19. The second generation Wide-Field/Planetary Camera on the Hubble Space Telescope

    NASA Technical Reports Server (NTRS)

    Leschly, Kim; Allestad, David; Herrell, Linda

    1991-01-01

    The general design and principal features of the second generation Wide-Field/Planetary Camera (WFPC-2) for the Hubble Space Telescope are reviewed. The discussion covers the background of WFPC-2 development, science capabilities, key performance parameters, optical and electronic equipment, mechanisms, thermal control, and contamination control. Attention is also given to on-orbit operations, including commanding and telemetry and on-orbit servicing.

  20. Past, present, and future of optical design at the College of Optical Sciences

    NASA Astrophysics Data System (ADS)

    Sasián, José

    2014-09-01

    The College of Optical Sciences, OSC, has seen three periods of optical design teaching and development. The first years 1964-1969; the golden years 1970-1999; and the new millennia years. Today the college offers a comprehensive and professional curriculum in optical design learning, and enjoys a strong heritage in optical design. This paper provides a perspective into the history and future prospects in optical design at the OSC.

  1. Wide-Field Raman Imaging of Dental Lesions

    PubMed Central

    Yang, Shan; Li, Bolan; Akkus, Anna; Akkus, Ozan; Lang, Lisa

    2014-01-01

    Detection of dental caries at the onset remains as a great challenge in dentistry. Raman spectroscopy could be successfully applied towards detecting caries since it is sensitive to the amount of the Raman active mineral crystals, the most abundant component of enamel. Effective diagnosis requires full examination of a tooth surface via a Raman mapping. Point-scan Raman mapping is not clinically relevant (feasible) due to lengthy data acquisition time. In this work, a wide-field Raman imaging system was assembled based on a high-sensitivity 2D CCD camera for imaging the mineralization status of teeth with lesions. Wide-field images indicated some lesions to be hypomineralized and others to be hypermineralized. The observations of wide-field Raman imaging were in agreement with point-scan Raman mapping. Therefore, sound enamel and lesions can be discriminated by Raman imaging of the mineral content. In conclusion, wide-field Raman imaging is a potentially useful tool for visualization of dental lesions in the clinic. PMID:24781363

  2. Wide-field lensfree imaging of tissue slides

    NASA Astrophysics Data System (ADS)

    Morel, Sophie Nhu An; Delon, Antoine; Blandin, Pierre; Bordy, Thomas; Cioni, Olivier; Hervé, Lionel; Fromentin, Catherine; Dinten, Jean-Marc; Allier, Cédric

    2015-07-01

    We developed a new imaging tool that can help pathologists in recording wide-field images of tissue slides. We present a simple cost-effective lens-free imaging method to record 2-4μm resolution wide-field (10 mm2 - 6 cm2) images of stained and unstained tissue slides. To our knowledge, our method is the first technique that enables fast (less than 5 minutes) wide-field lens-free imaging of such dense samples. Multiple holograms are recorded with different wavelength illumination, and a multispectral algorithm is used to retrieve both amplitude and phase. Our method can be used to retrieve images of stained tissue slides. For such absorbing object, the useful information is included in the modulus of the reconstructed complex field. Our method can also be applied to retrieve images of unstained tissue slides, where the useful information is in the retrieved phase. This technique is much cheaper and compact than a conventional microscope and could be made portable. Moreover, it enables wide field unstained tissue slides imaging, which could quickly provide useful information, for example on frozen section biopsies, when a rapid diagnosis is needed during surgery.

  3. Conceptual design of wide-field focal plane with InGaAs image sensors

    NASA Astrophysics Data System (ADS)

    Komiyama, Y.; Nakaya, H.; Kashikawa, N.; Uchida, T.

    2016-08-01

    We present a conceptual design to implement wide-field focal plane assembly with InGaAs image sensors which are being tested intensively and reveled to be promising for astronomical use. InGaAs image sensors are sensitive up to 1.7 microns and would open a new window for the wide-field near-infrared (NIR) imaging survey once large format sensors are developed. The sensors are not necessarily cooled down to below 100 K, which is the case for prevailing NIR image sensors such as HgCdTe, enabling us to develop the NIR camera based on the technique developed for the CCD camera in optical wavelength. The major technical challenges to employ InGaAS image sensors for wide-field NIR camera are implementation of focal plane assembly and thermal design. In this article, we discuss these difficulties and show how we can conquer based on our experience to build Hyper Suprime-Cam, which is a wide-field imager with 116 2k4k CCDs attached to Subaru Telescope.

  4. Dynamic Optical Networks for Future Internet Environments

    NASA Astrophysics Data System (ADS)

    Matera, Francesco

    2014-05-01

    This article reports an overview on the evolution of the optical network scenario taking into account the exponential growth of connected devices, big data, and cloud computing that is driving a concrete transformation impacting the information and communication technology world. This hyper-connected scenario is deeply affecting relationships between individuals, enterprises, citizens, and public administrations, fostering innovative use cases in practically any environment and market, and introducing new opportunities and new challenges. The successful realization of this hyper-connected scenario depends on different elements of the ecosystem. In particular, it builds on connectivity and functionalities allowed by converged next-generation networks and their capacity to support and integrate with the Internet of Things, machine-to-machine, and cloud computing. This article aims at providing some hints of this scenario to contribute to analyze impacts on optical system and network issues and requirements. In particular, the role of the software-defined network is investigated by taking into account all scenarios regarding data centers, cloud computing, and machine-to-machine and trying to illustrate all the advantages that could be introduced by advanced optical communications.

  5. Si photonics technology for future optical interconnection

    NASA Astrophysics Data System (ADS)

    Zheng, Xuezhe; Krishnamoorthy, Ashok V.

    2011-12-01

    Scaling of computing systems require ultra-efficient interconnects with large bandwidth density. Silicon photonics offers a disruptive solution with advantages in reach, energy efficiency and bandwidth density. We review our progress in developing building blocks for ultra-efficient WDM silicon photonic links. Employing microsolder based hybrid integration with low parasitics and high density, we optimize photonic devices on SOI platforms and VLSI circuits on more advanced bulk CMOS technology nodes independently. Progressively, we successfully demonstrated single channel hybrid silicon photonic transceivers at 5 Gbps and 10 Gbps, and 80 Gbps arrayed WDM silicon photonic transceiver using reverse biased depletion ring modulators and Ge waveguide photo detectors. Record-high energy efficiency of less than 100fJ/bit and 385 fJ/bit were achieved for the hybrid integrated transmitter and receiver, respectively. Waveguide grating based optical proximity couplers were developed with low loss and large optical bandwidth to enable multi-layer intra/inter-chip optical interconnects. Thermal engineering of WDM devices by selective substrate removal, together with WDM link using synthetic wavelength comb, we significantly improved the device tuning efficiency and reduced the tuning range. Using these innovative techniques, two orders of magnitude tuning power reduction was achieved. And tuning cost of only a few 10s of fJ/bit is expected for high data rate WDM silicon photonic links.

  6. HST Wide Field Camera 3: Instrument Status and Advice for Cycle 25 Proposers

    NASA Astrophysics Data System (ADS)

    Momcheva, Ivelina G.; WFC3 Instrument Team

    2017-01-01

    The Wide Field Camera 3 on-board of the Hubble Space Telescope provides astronomers with powerful imaging and slitless spectroscopic capabilities from the near-ultraviolet (200 nm) to the near-infrared (1700 nm). We summarize the basic characteristics and performances of WFC3, highlight changes in the calibration pipeline, summarize the calibration program for Cycle 24, and provide new information useful for observers planning to apply for future science investigations.

  7. Wide-field turbulence imaging with beam emission spectroscopy

    SciTech Connect

    McKee, G. R.; Fonck, R. J.; Uzun-Kaymak, I. U.; Yan, Z.; Shafer, M. W.

    2010-10-15

    Imaging of the size, shape, time-averaged, and time-resolved dynamics of long-wavelength density turbulence structures is accomplished with an expanded, high-sensitivity, wide-field beam emission spectroscopy (BES) diagnostic on DIII-D. A 64-channel BES system is configured with an 8x8 grid of discrete channels that image an approximately 7x9 cm region at the outboard midplane. The grid covers multiple correlation lengths and each channel shape matches the measured radial-poloidal correlation length asymmetry of turbulent eddies. The wide field 8x8 imaging capability allows for sampling of essentially the full two-dimensional spatial correlation function for typical plasma conditions. The sampled area can be radially scanned over 0.4

  8. In-Flight Performance of Wide Field Camera 3

    NASA Technical Reports Server (NTRS)

    Kimble, Randy

    2010-01-01

    Wide Field Camera 3 (WFC3), a powerful new UVNisible/IR imager, was installed into HST during Servicing Mission 4. After a successful commissioning in the Servicing Mission Orbital Verification program, WFC3 has been engaged in an exciting program of scientific observations. I review here the in-flight scientific performance of the instrument, addressing such topics as image quality, sensitivity, detector performance, and stability.

  9. Wide-field quantitative imaging of tissue microstructure using sub-diffuse spatial frequency domain imaging.

    PubMed

    McClatchy, David M; Rizzo, Elizabeth J; Wells, Wendy A; Cheney, Philip P; Hwang, Jeeseong C; Paulsen, Keith D; Pogue, Brian W; Kanick, Stephen C

    2016-06-20

    Localized measurements of scattering in biological tissue provide sensitivity to microstructural morphology but have limited utility to wide-field applications, such as surgical guidance. This study introduces sub-diffusive spatial frequency domain imaging (sd-SFDI), which uses high spatial frequency illumination to achieve wide-field sampling of localized reflectances. Model-based inversion recovers macroscopic variations in the reduced scattering coefficient [Formula: see text] and the phase function backscatter parameter (γ). Measurements in optical phantoms show quantitative imaging of user-tuned phase-function-based contrast with accurate decoupling of parameters that define both the density and the size-scale distribution of scatterers. Measurements of fresh ex vivo breast tissue samples revealed, for the first time, unique clustering of sub-diffusive scattering properties for different tissue types. The results support that sd-SFDI provides maps of microscopic structural biomarkers that cannot be obtained with diffuse wide-field imaging and characterizes spatial variations not resolved by point-based optical sampling.

  10. Foregrounds in Wide-field Redshifted 21 cm Power Spectra

    NASA Astrophysics Data System (ADS)

    Thyagarajan, Nithyanandan; Jacobs, Daniel C.; Bowman, Judd D.; Barry, N.; Beardsley, A. P.; Bernardi, G.; Briggs, F.; Cappallo, R. J.; Carroll, P.; Corey, B. E.; de Oliveira-Costa, A.; Dillon, Joshua S.; Emrich, D.; Ewall-Wice, A.; Feng, L.; Goeke, R.; Greenhill, L. J.; Hazelton, B. J.; Hewitt, J. N.; Hurley-Walker, N.; Johnston-Hollitt, M.; Kaplan, D. L.; Kasper, J. C.; Kim, Han-Seek; Kittiwisit, P.; Kratzenberg, E.; Lenc, E.; Line, J.; Loeb, A.; Lonsdale, C. J.; Lynch, M. J.; McKinley, B.; McWhirter, S. R.; Mitchell, D. A.; Morales, M. F.; Morgan, E.; Neben, A. R.; Oberoi, D.; Offringa, A. R.; Ord, S. M.; Paul, Sourabh; Pindor, B.; Pober, J. C.; Prabu, T.; Procopio, P.; Riding, J.; Rogers, A. E. E.; Roshi, A.; Udaya Shankar, N.; Sethi, Shiv K.; Srivani, K. S.; Subrahmanyan, R.; Sullivan, I. S.; Tegmark, M.; Tingay, S. J.; Trott, C. M.; Waterson, M.; Wayth, R. B.; Webster, R. L.; Whitney, A. R.; Williams, A.; Williams, C. L.; Wu, C.; Wyithe, J. S. B.

    2015-05-01

    Detection of 21 cm emission of H i from the epoch of reionization, at redshifts z\\gt 6, is limited primarily by foreground emission. We investigate the signatures of wide-field measurements and an all-sky foreground model using the delay spectrum technique that maps the measurements to foreground object locations through signal delays between antenna pairs. We demonstrate interferometric measurements are inherently sensitive to all scales, including the largest angular scales, owing to the nature of wide-field measurements. These wide-field effects are generic to all observations but antenna shapes impact their amplitudes substantially. A dish-shaped antenna yields the most desirable features from a foreground contamination viewpoint, relative to a dipole or a phased array. Comparing data from recent Murchison Widefield Array observations, we demonstrate that the foreground signatures that have the largest impact on the H i signal arise from power received far away from the primary field of view. We identify diffuse emission near the horizon as a significant contributing factor, even on wide antenna spacings that usually represent structures on small scales. For signals entering through the primary field of view, compact emission dominates the foreground contamination. These two mechanisms imprint a characteristic pitchfork signature on the “foreground wedge” in Fourier delay space. Based on these results, we propose that selective down-weighting of data based on antenna spacing and time can mitigate foreground contamination substantially by a factor of ∼100 with negligible loss of sensitivity.

  11. Quantitative phase imaging by wide field lensless digital holographic microscope

    NASA Astrophysics Data System (ADS)

    Adinda-Ougba, A.; Koukourakis, N.; Essaidi, A.; Ger­hardt, N. C.; Hofmann, M. R.

    2015-05-01

    Wide field, lensless microscopes have been developed for telemedicine and for resource limited setting [1]. They are based on in-line digital holography which is capable to provide amplitude and phase information resulting from numerical reconstruction. The phase information enables achieving axial resolution in the nanometer range. Hence, such microscopes provide a powerful tool to determine three-dimensional topologies of microstructures. In this contribution, a compact, low-cost, wide field, lensless microscope is presented, which is capable of providing topological profiles of microstructures in transparent material. Our setup consist only of two main components: a CMOSsensor chip and a laser diode without any need of a pinhole. We use this very simple setup to record holograms of microobjects. A wide field of view of ~24 mm², and a lateral resolution of ~2 μm are achieved. Moreover, amplitude and phase information are obtained from the numerical reconstruction of the holograms using a phase retrieval algorithm together with the angular spectrum propagation method. Topographic information of highly transparent micro-objects is obtained from the phase data. We evaluate our system by recording holograms of lines with different depths written by a focused laser beam. A reliable characterization of laser written microstructures is crucial for their functionality. Our results show that this system is valuable for determination of topological profiles of microstructures in transparent material.

  12. Prime focus wide-field corrector designs with lossless atmospheric dispersion correction

    SciTech Connect

    Saunders, Will; Gillingham, Peter; Smith, Greg; Kent, Steve; Doel, Peter

    2014-07-18

    Wide-Field Corrector designs are presented for the Blanco and Mayall telescopes, the CFHT and the AAT. The designs are Terezibh-style, with 5 or 6 lenses, and modest negative optical power. They have 2.2-3 degree fields of view, with curved and telecentric focal surfaces suitable for fiber spectroscopy. Some variants also allow wide-field imaging, by changing the last WFC element. Apart from the adaptation of the Terebizh design for spectroscopy, the key feature is a new concept for a 'Compensating Lateral Atmospheric Dispersion Corrector', with two of the lenses being movable laterally by small amounts. This provides excellent atmospheric dispersion correction, without any additional surfaces or absorption. A novel and simple mechanism for providing the required lens motions is proposed, which requires just 3 linear actuators for each of the two moving lenses.

  13. The Wide-Field Imaging Interferometry Testbed: Enabling Techniques for High Angular Resolution Astronomy

    NASA Technical Reports Server (NTRS)

    Rinehart, S. A.; Armstrong, T.; Frey, Bradley J.; Jung, J.; Kirk, J.; Leisawitz, David T.; Leviton, Douglas B.; Lyon, R.; Maher, Stephen; Martino, Anthony J.; Pauls, T.

    2007-01-01

    The Wide-Field Imaging Interferometry Testbed (WIIT) was designed to develop techniques for wide-field of view imaging interferometry, using "double-Fourier" methods. These techniques will be important for a wide range of future spacebased interferometry missions. We have provided simple demonstrations of the methodology already, and continuing development of the testbed will lead to higher data rates, improved data quality, and refined algorithms for image reconstruction. At present, the testbed effort includes five lines of development; automation of the testbed, operation in an improved environment, acquisition of large high-quality datasets, development of image reconstruction algorithms, and analytical modeling of the testbed. We discuss the progress made towards the first four of these goals; the analytical modeling is discussed in a separate paper within this conference.

  14. Science Archives at the Wide Field Astronomy Unit

    NASA Astrophysics Data System (ADS)

    Blake, R.; Read, M.; Sutorius, E.; Hambly, N.; Cross, N.; Collins, R.; Holliman, M.; Mann, B.

    The Wide Field Astronomy Unit (WFAU) at the Royal Observatory, Edinburgh (ROE) has been producing archives of astronomy data for more than a decade. It houses a collection of over 80 billion individual detections spread across five major astronomical surveys dating back over 60 years. As well as these surveys, we also host copies of external surveys to allow the cross-referencing of sources in our surveys with those detected with other instruments. This article details the data held by WFAU and the services we provide to our users.

  15. SSC Geopositional Assessment of the Advanced Wide Field Sensor

    NASA Technical Reports Server (NTRS)

    Ross, Kenton

    2006-01-01

    The geopositional accuracy of the standard geocorrected product from the Advanced Wide Field Sensor (AWiFS) was evaluated using digital orthophoto quarter quadrangles and other reference sources of similar accuracy. Images were analyzed from summer 2004 through spring 2005. Forty to fifty check points were collected manually per scene and analyzed to determine overall circular error, estimates of horizontal bias, and other systematic errors. Measured errors were somewhat higher than the specifications for the data, but they were consistent with the analysis of the distributing vendor.

  16. A ROSAT Wide Field Camera search for XUV bursts

    NASA Astrophysics Data System (ADS)

    Owens, Alan; Page, Clive G.; Sembay, S.; Schaefer, Bradley E.

    1993-02-01

    We have searched the ROSAT Wide Field Camera all-sky survey for short time-scale (less than 50 s) XUV bursts down to a limiting count of 5 x 10 exp -3 count/sq arcmin, corresponding to an incident flux of about 3 x 10 exp -10 erg/sq cm. In a total observation period of 171 d covering the entire sky, we found no evidence for such events. The present results are used to place limits on the log N-log S relation for gamma-ray bursts and constraints on the spectral shape of the previously reported ultrasoft X-ray transients.

  17. Wide field fluorescence imaging in narrow passageways using scanning fiber endoscope technology

    NASA Astrophysics Data System (ADS)

    Lee, Cameron M.; Chandler, John E.; Seibel, Eric J.

    2010-02-01

    An ultrathin scanning fiber endoscope (SFE) has been developed for high resolution imaging of regions in the body that are commonly inaccessible. The SFE produces 500 line color images at 30 Hz frame rate while maintaining a 1.2-1.7 mm outer diameter. The distal tip of the SFE houses a 9 mm rigid scan engine attached to a highly flexible tether (minimum bend radius < 8 mm) comprised of optical fibers and electrical wires within a protective sheath. Unlike other ultrathin technologies, the unique characteristics of this system have allowed the SFE to navigate narrow passages without sacrificing image quality. To date, the SFE has been used for in vivo imaging of the bile duct, esophagus and peripheral airways. In this study, the standard SFE operation was tailored to capture wide field fluorescence images and spectra. Green (523 nm) and blue (440 nm) lasers were used as illumination sources, while the white balance gain values were adjusted to accentuate red fluorescence signal. To demonstrate wide field fluorescence imaging of small lumens, the SFE was inserted into a phantom model of a human pancreatobiliary tract and navigated to a custom fluorescent target. Both wide field fluorescence and standard color images of the target were captured to demonstrate multimodal imaging.

  18. The Wide-Field Imager for Solar Probe Plus (WISPR)

    NASA Astrophysics Data System (ADS)

    Vourlidas, Angelos; Howard, Russell A.; Plunkett, Simon P.; Korendyke, Clarence M.; Thernisien, Arnaud F. R.; Wang, Dennis; Rich, Nathan; Carter, Michael T.; Chua, Damien H.; Socker, Dennis G.; Linton, Mark G.; Morrill, Jeff S.; Lynch, Sean; Thurn, Adam; Van Duyne, Peter; Hagood, Robert; Clifford, Greg; Grey, Phares J.; Velli, Marco; Liewer, Paulett C.; Hall, Jeffrey R.; DeJong, Eric M.; Mikic, Zoran; Rochus, Pierre; Mazy, Emanuel; Bothmer, Volker; Rodmann, Jens

    2016-12-01

    The Wide-field Imager for Solar PRobe Plus (WISPR) is the sole imager aboard the Solar Probe Plus (SPP) mission scheduled for launch in 2018. SPP will be a unique mission designed to orbit as close as 7 million km (9.86 solar radii) from Sun center. WISPR employs a 95∘ radial by 58∘ transverse field of view to image the fine-scale structure of the solar corona, derive the 3D structure of the large-scale corona, and determine whether a dust-free zone exists near the Sun. WISPR is the smallest heliospheric imager to date yet it comprises two nested wide-field telescopes with large-format (2 K × 2 K) APS CMOS detectors to optimize the performance for their respective fields of view and to minimize the risk of dust damage, which may be considerable close to the Sun. The WISPR electronics are very flexible allowing the collection of individual images at cadences up to 1 second at perihelion or the summing of multiple images to increase the signal-to-noise when the spacecraft is further from the Sun. The dependency of the Thomson scattering emission of the corona on the imaging geometry dictates that WISPR will be very sensitive to the emission from plasma close to the spacecraft in contrast to the situation for imaging from Earth orbit. WISPR will be the first `local' imager providing a crucial link between the large-scale corona and the in-situ measurements.

  19. Mitigating fluorescence spectral overlap in wide-field endoscopic imaging

    PubMed Central

    Hou, Vivian; Nelson, Leonard Y.; Seibel, Eric J.

    2013-01-01

    Abstract. The number of molecular species suitable for multispectral fluorescence imaging is limited due to the overlap of the emission spectra of indicator fluorophores, e.g., dyes and nanoparticles. To remove fluorophore emission cross-talk in wide-field multispectral fluorescence molecular imaging, we evaluate three different solutions: (1) image stitching, (2) concurrent imaging with cross-talk ratio subtraction algorithm, and (3) frame-sequential imaging. A phantom with fluorophore emission cross-talk is fabricated, and a 1.2-mm ultrathin scanning fiber endoscope (SFE) is used to test and compare these approaches. Results show that fluorophore emission cross-talk could be successfully avoided or significantly reduced. Near term, the concurrent imaging method of wide-field multispectral fluorescence SFE is viable for early stage cancer detection and localization in vivo. Furthermore, a means to enhance exogenous fluorescence target-to-background ratio by the reduction of tissue autofluorescence background is demonstrated. PMID:23966226

  20. Science with a wide-field UV transient explorer

    SciTech Connect

    Sagiv, I.; Gal-Yam, A.; Ofek, E. O.; Waxman, E.; Trakhtenbrot, B.; Topaz, J.; Aharonson, O.; Kulkarni, S. R.; Phinney, E. S.; Nakar, E.; Maoz, D.; Beichman, C.; Murthy, J.; Worden, S. P.

    2014-04-01

    The time-variable electromagnetic sky has been well-explored at a wide range of wavelengths. In contrast, the ultra-violet (UV) variable sky is relatively poorly explored, even though it offers exciting scientific prospects. Here, we review the potential scientific impact of a wide-field UV survey on the study of explosive and other transient events, as well as known classes of variable objects, such as active galactic nuclei and variable stars. We quantify our predictions using a fiducial set of observational parameters which are similar to those envisaged for the proposed ULTRASAT mission. We show that such a mission would be able to revolutionize our knowledge about massive star explosions by measuring the early UV emission from hundreds of events, revealing key physical parameters of the exploding progenitor stars. Such a mission would also detect the UV emission from many tens of tidal-disruption events of stars by supermassive black holes at galactic nuclei and enable a measurement of the rate of such events. The overlap of such a wide-field UV mission with existing and planned gravitational-wave and high-energy neutrino telescopes makes it especially timely.

  1. In-vivo performance comparison study of wide-field oxygenation imaging methods

    NASA Astrophysics Data System (ADS)

    Van de Giessen, Martijn; Angelo, Joseph; Vargas, Christina; Gioux, Sylvain

    2015-03-01

    Wide-field oxygenation saturation (StO2) estimates can be clinically very advantageous. Particularly when implemented in a non-contact manner, applications such as intra-operative assessment of tissue perfusion are very promising. Nevertheless, wide-field optical oxygenation imaging did not yet successfully translate to the clinic. In this work we compare four proposed methods for wide-field imaging that are based on different photon propagation models and that depend on different sets of assumed parameters such as absorption and reduced scattering coefficients. We investigated these for methods, with particular attention to sensitivities to errors in assumed parameters of calibration estimates. To this end we acquired an in vivo time series of a pig skin flap with a venous occlusion. StO2 estimates of all methods were compared to estimates from spatial frequency domain imaging of the same time series. Correct assumptions on scatter power and accurate calibration were found to be the most important prerequisites for accurate StO2 estimates. Although all models were able to measure relative changes in StO2 when the occlusion was applied and released, only the models that incorporated assumed reduced scattering coefficients estimated StO2 values within 5% of the expected values (estimated using SFDI). An important aspect of the compared methods is their ability to be used for real-time imaging. With the addition of real-time calibration and robust tissue scattering estimates, real-time wide-field imaging of oxygenation saturation can prove to provide important added value in the clinic.

  2. The High-Speed and Wide-Field TORTORA Camera: description & results .

    NASA Astrophysics Data System (ADS)

    Greco, G.; Beskin, G.; Karpov, S.; Guarnieri, A.; Bartolini, C.; Bondar, S.; Piccioni, A.; Molinari, E.

    We present the description and the most significant results of the wide-field and ultra-fast TORTORA camera devoted to the investigation of rapid changes in light intensity in a phenomenon occurring within an extremely short period of time and randomly distributed over the sky. In particular, the ground-based TORTORA observations synchronized with the gamma -ray BAT telescope on board of the Swift satellite has permitted to trace the optical burst time-structure of the Naked-Eye GRB 080319B with an unprecedented level of accuracy.

  3. Real-time monitoring of graphene patterning with wide-field four-wave mixing microscopy

    NASA Astrophysics Data System (ADS)

    Koivistoinen, Juha; Aumanen, Jukka; Hiltunen, Vesa-Matti; Myllyperkiö, Pasi; Johansson, Andreas; Pettersson, Mika

    2016-04-01

    The single atom thick two-dimensional graphene is a promising material for various applications due to its extraordinary electronic, optical, optoelectronic, and mechanical properties. The demand for developing graphene based applications has entailed a requirement for development of methods for fast imaging techniques for graphene. Here, we demonstrate imaging of graphene with femtosecond wide-field four-wave mixing microscopy. The method provides a sensitive, non-destructive approach for rapid large area characterization of graphene. We show that the method is suitable for online following of a laser patterning process of microscale structures on single-layer graphene.

  4. Range performance of the DARPA AWARE wide field-of-view visible imager.

    PubMed

    Nichols, J M; Judd, K P; Olson, C C; Novak, K; Waterman, J R; Feller, S; McCain, S; Anderson, J; Brady, D

    2016-06-01

    In a prior paper, we described a new imaging architecture that addresses the need for wide field-of-view imaging combined with the resolution required to identify targets at long range. Over the last two years substantive improvements have been made to the system, both in terms of the size, weight, and power of the camera as well as to the optics and data management software. The result is an overall improvement in system performance, which we demonstrate via a maritime target identification experiment.

  5. Wide field x-ray telescopes: Detecting x-ray transients/afterglows related to GRBs

    SciTech Connect

    Hudec, Rene; Pina, Ladislav; Inneman, Adolf; Gorenstein, Paul

    1998-05-16

    The recent discovery of X-ray afterglows of GRBs opens the possibility of analyses of GRBs by their X-ray detections. However, imaging X-ray telescopes in current use mostly have limited fields of view. Alternative X-ray optics geometries achieving very large fields of view have been theoretically suggested in the 70's but not constructed and used so far. We review the geometries and basic properties of the wide-field X-ray optical systems based on one- and two-dimensional lobster-eye geometry and suggest technologies for their development and construction. First results of the development of double replicated X-ray reflecting flats for use in one-dimensional X-ray optics of lobster-eye type are presented and discussed. The optimum strategy for locating GRBs upon their X-ray counterparts is also presented and discussed.

  6. A Parallel Imaging Approach to Wide-field MR Microscopy

    PubMed Central

    McDougall, Mary Preston; Wright, Steven M.

    2011-01-01

    Magnetic resonance microscopy (MRM), suggested in the earliest papers on MRI, has always been limited by the low signal-to-noise ratio (SNR) resulting from the small voxel size. MRM has largely been enabled by the use of microcoils which provide the SNR improvement required to overcome this limitation. Concomitant with the small coils is a small field-of-view, which limits the use of MRM as a histological tool or for imaging large regions in general. This paper describes initial results in wide field-of-view MR microscopy using a large array of narrow, parallel coils, which provides an SNR enhancement as well as the ability to use parallel imaging techniques. Comparison images made between a volume coil and the proposed technique demonstrate reductions in imaging time of over 100 with no loss in SNR or resolution. PMID:22139858

  7. Development of stable monolithic wide-field Michelson interferometers

    NASA Astrophysics Data System (ADS)

    Wan, Xiaoke; Ge, Jian; Chen, Zhiping

    2011-07-01

    Bulk wide-field Michelson interferometers are very useful for high precision applications in remote sensing and astronomy. A stable monolithic Michelson interferometer is a key element in high precision radial velocity (RV) measurements for extrasolar planets searching and studies. Thermal stress analysis shows that matching coefficients of thermal expansion (CTEs) is a critical requirement for ensuring interferometer stability. This requirement leads to a novel design using BK7 and LAK7 materials, such that the monolithic interferometer is free from thermal distortion. The processes of design, fabrication, and testing of interferometers are described in detail. In performance evaluations, the field angle is typically 23.8° and thermal sensitivity is typically -2.6×10-6/° C near 550nm, which corresponds to ˜800m/s/°C in the RV scale. Low-cost interferometer products have been commissioned in multiple RV instruments, and they are producing high stability performance over long term operations.

  8. Wide Field X-Ray Telescope Mission Concept Study Results

    NASA Technical Reports Server (NTRS)

    Hopkins, R. C.; Thomas, H. D.; Fabisinski, L. L.; Baysinger, M.; Hornsby, L. S.; Maples, C. D.; Purlee, T. E.; Capizzo, P. D.; Percy, T. K.

    2014-01-01

    The Wide Field X-Ray Telescope (WFXT) is an astrophysics mission concept for detecting and studying extra-galactic x-ray sources, including active galactic nuclei and clusters of galaxies, in an effort to further understand cosmic evolution and structure. This Technical Memorandum details the results of a mission concept study completed by the Advanced Concepts Office at NASA Marshall Space Flight Center in 2012. The design team analyzed the mission and instrument requirements, and designed a spacecraft that enables the WFXT mission while using high heritage components. Design work included selecting components and sizing subsystems for power, avionics, guidance, navigation and control, propulsion, structures, command and data handling, communications, and thermal control.

  9. On illumination schemes for wide-field CARS microscopy.

    PubMed

    Toytman, I; Simanovskii, D; Palanker, D

    2009-04-27

    New system for a wide-field CARS microscopy is demonstrated, including two schemes of non-phase-matching illumination. Several advantages including high Stokes pulse energy, pulse-to-pulse stability and inherent synchronization between pump and Stokes pulses were brought by use of methane-filled Raman converter. Spatial resolution of the system with axially symmetric illumination, 0.5 microm, was found to correspond to diffraction limit of the imaging objective. Selective sensitivity to lipid-rich myelin sheaths in the nerve tissue has been demonstrated and confirmed by comparison with histological samples stained with myelin-specific dye. Single-shot imaging capability of the system has been demonstrated with a speckling-free illumination on a monolayer of 3 microm polystyrene beads.

  10. Development of stable monolithic wide-field Michelson interferometers.

    PubMed

    Wan, Xiaoke; Ge, Jian; Chen, Zhiping

    2011-07-20

    Bulk wide-field Michelson interferometers are very useful for high precision applications in remote sensing and astronomy. A stable monolithic Michelson interferometer is a key element in high precision radial velocity (RV) measurements for extrasolar planets searching and studies. Thermal stress analysis shows that matching coefficients of thermal expansion (CTEs) is a critical requirement for ensuring interferometer stability. This requirement leads to a novel design using BK7 and LAK7 materials, such that the monolithic interferometer is free from thermal distortion. The processes of design, fabrication, and testing of interferometers are described in detail. In performance evaluations, the field angle is typically 23.8° and thermal sensitivity is typically -2.6×10(-6)/°C near 550 nm, which corresponds to ∼800 m/s/°C in the RV scale. Low-cost interferometer products have been commissioned in multiple RV instruments, and they are producing high stability performance over long term operations.

  11. Wide-Field-of-View, High-Resolution, Stereoscopic Imager

    NASA Technical Reports Server (NTRS)

    Prechtl, Eric F.; Sedwick, Raymond J.

    2010-01-01

    A device combines video feeds from multiple cameras to provide wide-field-of-view, high-resolution, stereoscopic video to the user. The prototype under development consists of two camera assemblies, one for each eye. One of these assemblies incorporates a mounting structure with multiple cameras attached at offset angles. The video signals from the cameras are fed to a central processing platform where each frame is color processed and mapped into a single contiguous wide-field-of-view image. Because the resolution of most display devices is typically smaller than the processed map, a cropped portion of the video feed is output to the display device. The positioning of the cropped window will likely be controlled through the use of a head tracking device, allowing the user to turn his or her head side-to-side or up and down to view different portions of the captured image. There are multiple options for the display of the stereoscopic image. The use of head mounted displays is one likely implementation. However, the use of 3D projection technologies is another potential technology under consideration, The technology can be adapted in a multitude of ways. The computing platform is scalable, such that the number, resolution, and sensitivity of the cameras can be leveraged to improve image resolution and field of view. Miniaturization efforts can be pursued to shrink the package down for better mobility. Power savings studies can be performed to enable unattended, remote sensing packages. Image compression and transmission technologies can be incorporated to enable an improved telepresence experience.

  12. Adaptive optics high resolution spectroscopy: present status and future direction

    SciTech Connect

    Alcock, C; Angel, R; Ciarlo, D; Fugate, R O; Ge, J; Kuzmenko, P; Lloyd-Hart, M; Macintosh, B; Najita, J; Woolf, N

    1999-07-27

    High resolution spectroscopy experiments with visible adaptive optics (AO) telescopes at Starfire Optical Range and Mt. Wilson have demonstrated that spectral resolution can be routinely improved by a factor of - 10 over the seeing-limited case with no extra light losses at visible wavelengths. With large CCDs now available, a very wide wavelength range can be covered in a single exposure. In the near future, most large ground-based telescopes will be equipped with powerful A0 systems. Most of these systems are aimed primarily at diffraction-limited operation in the near IR. An exciting new opportunity will thus open up for high resolution IR spectroscopy. Immersion echelle gratings with much coarser grooves being developed by us at LLNL will play a critical role in achieving high spectral resolution with a compact and low cost IR cryogenically cooled spectrograph and simultaneous large wavelength coverage on relatively small IR detectors. We have constructed a new A0 optimized spectrograph at Steward Observatory to provide R = 200,000 in the optical, which is being commissioned at the Starfire Optical Range 3.5m telescope. We have completed the optical design of the LLNL IR Immersion Spectrograph (LISPEC) to take advantage of improved silicon etching technology. Key words: adaptive optics, spectroscopy, high resolution, immersion gratings

  13. DWARF IRREGULAR GALAXY LEO A: SUPRIME-CAM WIDE-FIELD STELLAR PHOTOMETRY

    SciTech Connect

    Stonkutė, Rima; Narbutis, Donatas; Vansevičius, Vladas; Arimoto, Nobuo; Hasegawa, Takashi; Tamura, Naoyuki

    2014-10-01

    We have surveyed a complete extent of Leo A—an apparently isolated gas-rich low-mass dwarf irregular galaxy in the Local Group. The B, V, and I passband CCD images (typical seeing ∼0.''8) were obtained with the Subaru Telescope equipped with the Suprime-Cam mosaic camera. The wide-field (20' × 24') photometry catalog of 38,856 objects (V ∼ 16-26 mag) is presented. This survey is also intended to serve as ''a finding chart'' for future imaging and spectroscopic observation programs of Leo A.

  14. Head & neck optical diagnostics: vision of the future of surgery

    PubMed Central

    Upile, Tahwinder; Jerjes, Waseem; Sterenborg, Henricus JCM; El-Naggar, Adel K; Sandison, Ann; Witjes, Max JH; Biel, Merrill A; Bigio, Irving; Wong, Brian JF; Gillenwater, Ann; MacRobert, Alexander J; Robinson, Dominic J; Betz, Christian S; Stepp, Herbert; Bolotine, Lina; McKenzie, Gordon; Mosse, Charles Alexander; Barr, Hugh; Chen, Zhongping; Berg, Kristian; D'Cruz, Anil K; Stone, Nicholas; Kendall, Catherine; Fisher, Sheila; Leunig, Andreas; Olivo, Malini; Richards-Kortum, Rebecca; Soo, Khee Chee; Bagnato, Vanderlei; Choo-Smith, Lin-Ping; Svanberg, Katarina; Tan, I Bing; Wilson, Brian C; Wolfsen, Herbert; Yodh, Arjun G; Hopper, Colin

    2009-01-01

    Review paper and Proceedings of the Inaugural Meeting of the Head and Neck Optical Diagnostics Society (HNODS) on March 14th 2009 at University College London. The aim of our research must be to provide breakthrough translational research which can be applied clinically in the immediate rather than the near future. We are fortunate that this is indeed a possibility and may fundamentally change current clinical and surgical practice to improve our patients' lives. PMID:19594907

  15. Wide-Field InfraRed Survey Telescope (WFIRST) Slitless Spectrometer: Design, Prototype, and Results

    NASA Technical Reports Server (NTRS)

    Gong, Qian; Content, David; Dominguez, Margaret; Emmett, Thomas; Griesmann, Ulf; Hagopian, John; Kruk, Jeffrey; Marx, Catherine; Pasquale, Bert; Wallace, Thomas; Whipple, Arthur

    2016-01-01

    The slitless spectrometer plays an important role in the Wide-Field InfraRed Survey Telescope (WFIRST) mission for the survey of emission-line galaxies. This will be an unprecedented very wide field, HST quality 3D survey of emission line galaxies. The concept of the compound grism as a slitless spectrometer has been presented previously. The presentation briefly discusses the challenges and solutions of the optical design, and recent specification updates, as well as a brief comparison between the prototype and the latest design. However, the emphasis of this paper is the progress of the grism prototype: the fabrication and test of the complicated diffractive optical elements and powered prism, as well as grism assembly alignment and testing. Especially how to use different tools and methods, such as IR phase shift and wavelength shift interferometry, to complete the element and assembly tests. The paper also presents very encouraging results from recent element tests to assembly tests. Finally we briefly touch the path forward plan to test the spectral characteristic, such as spectral resolution and response.

  16. Chronic wide-field imaging of brain hemodynamics in behaving animals

    PubMed Central

    Miao, Peng; Zhang, Lingke; Li, Miao; Zhang, Yiguang; Feng, Shihan; Wang, Qihong; Thakor, Nitish V.

    2016-01-01

    Chronically monitoring cerebral activities in awake and freely moving status is very important in physiological and pathological studies. We present a novel standalone micro-imager for monitoring the cerebral blood flow (CBF) and total hemoglobin (HbT) activities in freely moving animals using the laser speckle contrast imaging (LSCI) and optical intrinsic signal (OIS) methods. A new cranial window method, using contact lens and wide field optics, is also proposed to achieve the chronic and wide-field imaging of rat’s cerebral cortex. The hemodynamic activities of rats’ cortex were measured for the first time without restriction of cables or fibers in awake and behaving animals. Chronic imaging showed the increase of CBF and HbT in motor cortex when the rats were climbing on the cage wall. Interestingly, the CBF activation of supplying vessel was smaller than that of parenchyma. Furthermore, after the climbing, CBF demonstrated fully return to the baseline while HbT showed a delayed recovery. The standalone micro-imager technology provides new possibilities of brain imaging in cognitive neuroscience studies. PMID:28101429

  17. Space infrared telescope facility wide field and diffraction limited array camera (IRAC)

    NASA Technical Reports Server (NTRS)

    Fazio, Giovanni G.

    1988-01-01

    The wide-field and diffraction limited array camera (IRAC) is capable of two-dimensional photometry in either a wide-field or diffraction-limited mode over the wavelength range from 2 to 30 microns with a possible extension to 120 microns. A low-doped indium antimonide detector was developed for 1.8 to 5.0 microns, detectors were tested and optimized for the entire 1.8 to 30 micron range, beamsplitters were developed and tested for the 1.8 to 30 micron range, and tradeoff studies of the camera's optical system performed. Data are presented on the performance of InSb, Si:In, Si:Ga, and Si:Sb array detectors bumpbonded to a multiplexed CMOS readout chip of the source-follower type at SIRTF operating backgrounds (equal to or less than 1 x 10 to the 8th ph/sq cm/sec) and temperature (4 to 12 K). Some results at higher temperatures are also presented for comparison to SIRTF temperature results. Data are also presented on the performance of IRAC beamsplitters at room temperature at both 0 and 45 deg angle of incidence and on the performance of the all-reflecting optical system baselined for the camera.

  18. Wide-Field Infrared Survey Telescope (WFIRST) Interim Report

    NASA Technical Reports Server (NTRS)

    Green, J.; Schechter, P.; Baltay, C.; Bean, R.; Bennett, D.; Brown, R.; Conselice, C.; Donahue, M.; Gaudi, S.; Lauer, T.; Perlmutter, S.; Rauscher, B.; Rhodes, J.; Roellig, T.; Stern, D.; Sumi, T.; Gerhels, N.; Sambruna, R.; Barry, R. K.; Content, D.; Grady, K; Jackson, C.; Kruk, J.; Melton, M.; Rioux, N.

    2011-01-01

    The New Worlds, New Horizons (NWNH) in Astronomy and Astrophysics 2010 Decadal Survey prioritized the community consensus for ground-based and space-based observatories. Recognizing that many of the community s key questions could be answered with a wide-field infrared survey telescope in space, and that the decade would be one of budget austerity, WFIRST was top ranked in the large space mission category. In addition to the powerful new science that could be accomplished with a wide-field infrared telescope, the WFIRST mission was determined to be both technologically ready and only a small fraction of the cost of previous flagship missions, such as HST or JWST. In response to the top ranking by the community, NASA formed the WFIRST Science Definition Team (SDT) and Project Office. The SDT was charged with fleshing out the NWNH scientific requirements to a greater level of detail. NWNH evaluated the risk and cost of the JDEM-Omega mission design, as submitted by NASA, and stated that it should serve as the basis for the WFIRST mission. The SDT and Project Office were charged with developing a mission optimized for achieving the science goals laid out by the NWNH re-port. The SDT and Project Office opted to use the JDEM-Omega hardware configuration as an initial start-ing point for the hardware implementation. JDEM-Omega and WFIRST both have an infrared imager with a filter wheel, as well as counter-dispersed moderate resolution spectrometers. The primary advantage of space observations is being above the Earth's atmosphere, which absorbs, scatters, warps and emits light. Observing from above the atmosphere enables WFIRST to obtain precision infrared measurements of the shapes of galaxies for weak lensing, infrared light-curves of supernovae and exoplanet microlensing events with low systematic errors, and infrared measurements of the H hydrogen line to be cleanly detected in the 1

  19. Design and characterization of a combined OCT and wide field imaging falloposcope for ovarian cancer detection

    PubMed Central

    Keenan, Molly; Tate, Tyler H.; Kieu, Khanh; Black, John F.; Utzinger, Urs; Barton, Jennifer K.

    2016-01-01

    Early detection of ovarian cancer is only achieved in around 20% of women due to lack of effective screening. We propose a method for surveillance of high risk women based on a microendoscope introduced transvaginally to image the fallopian tubes and ovaries. This requires extreme miniaturization of the optics and catheter sheath. We describe the design of a falloposcope that combines optical coherence tomography (OCT) and wide field imaging into a sub-1 mm diameter package. We characterize the systems and show that they provide contrast on ex-vivo samples of ovary and fallopian tube. In addition, we show the mechanical performance of the endoscope in an anatomically correct model of the female reproductive tract. PMID:28101406

  20. Metrology of confined flows using wide field nanoparticle velocimetry

    PubMed Central

    Ranchon, Hubert; Picot, Vincent; Bancaud, Aurélien

    2015-01-01

    The manipulation of fluids in micro/nanofabricated systems opens new avenues to engineer the transport of matter at the molecular level. Yet the number of methods for the in situ characterization of fluid flows in shallow channels is limited. Here we establish a simple method called nanoparticle velocimetry distribution analysis (NVDA) that relies on wide field microscopy to measure the flow rate and channel height based on the fitting of particle velocity distributions along and across the flow direction. NVDA is validated by simulations, showing errors in velocity and height determination of less than 1% and 8% respectively, as well as with experiments, in which we monitor the behavior of 200 nm nanoparticles conveyed in channels of ~1.8 μm in height. We then show the relevance of this assay for the characterization of flows in bulging channels, and prove its suitability to characterize the concentration of particles across the channel height in the context of visco-elastic focusing. Our method for rapid and quantitative flow characterization has therefore a broad spectrum of applications in micro/nanofluidics, and a strong potential for the optimization of Lab-on-Chips modules in which engineering of confined transport is necessary. PMID:25974654

  1. PANGU: a wide field gamma-ray imager and polarimeter

    NASA Astrophysics Data System (ADS)

    Wu, X.; Walter, R.; Su, M.; Ambrosi, G.; Azzarello, P.; Böttcher, M.; Chang, J.; Chernyakova, M.; Fan, Y.; Farnier, C.; Gargano, F.; Grenier, I.; Hajdas, W.; Mazziotta, M. N.; Pearce, M.; Pohl, M.; Zdziarski, A.

    2016-07-01

    PANGU (the PAir-productioN Gamma-ray Unit) is a gamma-ray telescope with a wide field of view optimized for spectro-imaging, timing and polarization studies. It will map the gamma-ray sky from 10 MeV to a few GeV with unprecedented spatial resolution. This window on the Universe is unique to detect photons produced directly by relativistic particles, via the decay of neutral pions, or the annihilation or decay light from anti-matter and the putative light dark matter candidates. A wealth of questions can be probed among the most important themes of modern physics and astrophysics. The PANGU instrument is a pair-conversion gamma-ray telescope based on an innovative design of a silicon strip tracker. It is light, compact and accurate. It consists of 100 layers of silicon micro-strip detector of 80 x 80 cm2 in area, stacked to height of about 90 cm, and covered by an anticoincidence detector. PANGU relies on multiple scattering effects for energy measurement, reaching an energy resolution between 30-50% for 10 MeV - 1 GeV. The novel tracker will allow the first polarization measurement and provide the best angular resolution ever obtained in the soft gamma ray and GeV band.

  2. Wide Field-of-View Fluorescence Imaging of Coral Reefs

    PubMed Central

    Treibitz, Tali; Neal, Benjamin P.; Kline, David I.; Beijbom, Oscar; Roberts, Paul L. D.; Mitchell, B. Greg; Kriegman, David

    2015-01-01

    Coral reefs globally are declining rapidly because of both local and global stressors. Improved monitoring tools are urgently needed to understand the changes that are occurring at appropriate temporal and spatial scales. Coral fluorescence imaging tools have the potential to improve both ecological and physiological assessments. Although fluorescence imaging is regularly used for laboratory studies of corals, it has not yet been used for large-scale in situ assessments. Current obstacles to effective underwater fluorescence surveying include limited field-of-view due to low camera sensitivity, the need for nighttime deployment because of ambient light contamination, and the need for custom multispectral narrow band imaging systems to separate the signal into meaningful fluorescence bands. Here we describe the Fluorescence Imaging System (FluorIS), based on a consumer camera modified for greatly increased sensitivity to chlorophyll-a fluorescence, and we show high spectral correlation between acquired images and in situ spectrometer measurements. This system greatly facilitates underwater wide field-of-view fluorophore surveying during both night and day, and potentially enables improvements in semi-automated segmentation of live corals in coral reef photographs and juvenile coral surveys. PMID:25582836

  3. Wide field of view multifocal scanning microscopy with sparse sampling

    NASA Astrophysics Data System (ADS)

    Wang, Jie; Wu, Jigang

    2016-02-01

    We propose to use sparsely sampled line scans with a sparsity-based reconstruction method to obtain images in a wide field of view (WFOV) multifocal scanning microscope. In the WFOV microscope, we used a holographically generated irregular focus grid to scan the sample in one dimension and then reconstructed the sample image from line scans by measuring the transmission of the foci through the sample during scanning. The line scans were randomly spaced with average spacing larger than the Nyquist sampling requirement, and the image was recovered with sparsity-based reconstruction techniques. With this scheme, the acquisition data can be significantly reduced and the restriction for equally spaced foci positions can be removed, indicating simpler experimental requirement. We built a prototype system and demonstrated the effectiveness of the reconstruction by recovering microscopic images of a U.S. Air Force target and an onion skin cell microscope slide with 40, 60, and 80% missing data with respect to the Nyquist sampling requirement.

  4. Prowess - A Software Model for the Ooty Wide Field Array

    NASA Astrophysics Data System (ADS)

    Marthi, Visweshwar Ram

    2017-03-01

    One of the scientific objectives of the Ooty Wide Field Array (OWFA) is to observe the redshifted H i emission from z ˜ 3.35. Although predictions spell out optimistic outcomes in reasonable integration times, these studies were based purely on analytical assumptions, without accounting for limiting systematics. A software model for OWFA has been developed with a view to understanding the instrument-induced systematics, by describing a complete software model for the instrument. This model has been implemented through a suite of programs, together called Prowess, which has been conceived with the dual role of an emulator as well as observatory data analysis software. The programming philosophy followed in building Prowess enables a general user to define an own set of functions and add new functionality. This paper describes a co-ordinate system suitable for OWFA in which the baselines are defined. The foregrounds are simulated from their angular power spectra. The visibilities are then computed from the foregrounds. These visibilities are then used for further processing, such as calibration and power spectrum estimation. The package allows for rich visualization features in multiple output formats in an interactive fashion, giving the user an intuitive feel for the data. Prowess has been extensively used for numerical predictions of the foregrounds for the OWFA H i experiment.

  5. Wide field-of-view fluorescence imaging of coral reefs.

    PubMed

    Treibitz, Tali; Neal, Benjamin P; Kline, David I; Beijbom, Oscar; Roberts, Paul L D; Mitchell, B Greg; Kriegman, David

    2015-01-13

    Coral reefs globally are declining rapidly because of both local and global stressors. Improved monitoring tools are urgently needed to understand the changes that are occurring at appropriate temporal and spatial scales. Coral fluorescence imaging tools have the potential to improve both ecological and physiological assessments. Although fluorescence imaging is regularly used for laboratory studies of corals, it has not yet been used for large-scale in situ assessments. Current obstacles to effective underwater fluorescence surveying include limited field-of-view due to low camera sensitivity, the need for nighttime deployment because of ambient light contamination, and the need for custom multispectral narrow band imaging systems to separate the signal into meaningful fluorescence bands. Here we describe the Fluorescence Imaging System (FluorIS), based on a consumer camera modified for greatly increased sensitivity to chlorophyll-a fluorescence, and we show high spectral correlation between acquired images and in situ spectrometer measurements. This system greatly facilitates underwater wide field-of-view fluorophore surveying during both night and day, and potentially enables improvements in semi-automated segmentation of live corals in coral reef photographs and juvenile coral surveys.

  6. Wide-Field InfraRed Survey Telescope WFIRST

    NASA Technical Reports Server (NTRS)

    Green, J.; Schechter, P.; Baltay, C.; Bean, R.; Bennett, D.; Brown, R.; Conselice, C.; Donahue, M.; Fan, X.; Rauscher, B.; Rhodes, J.; Roellig, T.; Stern, D.; Gehrels, N.; Sambruna, R.; Traub, W.; Barry, R. K.; Content, D.; Goullioud, R.; Grady, K.; Kruk, J.; Melton, M.; Peddie, C.; Rioux, N.; Seiffert, M.

    2012-01-01

    In December 2010, NASA created a Science Definition Team (SDT) for WFIRST, the Wide Field Infra-Red Survey Telescope, recommended by the Astro 2010 Decadal Survey as the highest priority for a large space mission. The SDT was chartered to work with the WFIRST Project Office at GSFC and the Program Office at JPL to produce a Design Reference Mission (DRM) for WFIRST. Part of the original charge was to produce an interim design reference mission by mid-2011. That document was delivered to NASA and widely circulated within the astronomical community. In late 2011 the Astrophysics Division augmented its original charge, asking for two design reference missions. The first of these, DRM1, was to be a finalized version of the interim DRM, reducing overall mission costs where possible. The second of these, DRM2, was to identify and eliminate capabilities that overlapped with those of NASA's James Webb Space Telescope (henceforth JWST), ESA's Euclid mission, and the NSF's ground-based Large Synoptic Survey Telescope (henceforth LSST), and again to reduce overall mission cost, while staying faithful to NWNH. This report presents both DRM1 and DRM2.

  7. FRB Event Rate Predictions for the Ooty Wide Field Array

    NASA Astrophysics Data System (ADS)

    Bhattacharyya, Siddhartha; Bera, Apurba; Bharadwaj, Somnath; Ramesh Bhat, N. D.; Chengalur, Jayaram N.

    2017-03-01

    We developed a generic formalism to estimate the event rate and the redshift distribution of Fast Radio Bursts (FRBs) in our previous publication (Bera et al. 2016), considering FRBs are of an extragalactic origin. In this paper, we present (a) the predicted pulse widths of FRBs by considering two different scattering models, (b) the minimum total energy required to detect events, (c) the redshift distribution and (d) the detection rates of FRBs for the Ooty Wide Field Array (OWFA). The energy spectrum of FRBs is modelled as a power law with an exponent - α and our analysis spans a range -3≤ α≤5. We find that OWFA will be capable of detecting FRBs with α≥0. The redshift distribution and the event rates of FRBs are estimated by assuming two different energy distribution functions; a Delta function and a Schechter luminosity function with an exponent -2≤ γ≤2. We consider an empirical scattering model based on pulsar observations (model I) as well as a theoretical model (model II) expected for the intergalactic medium. The redshift distributions peak at a particular redshift z p for a fixed value of α, which lie in the range 0.3≤ z p ≤1 for the scattering model I and remain flat and extend up to high redshifts ( z≲5) for the scattering model II.

  8. Automatic detection of asteroids and meteoroids --- a wide-field survey

    NASA Astrophysics Data System (ADS)

    Vereš, P.; Tóth, J.; Jedicke, R.; Tonry, J.; Denneau, L.; Wainscoat, R.; Kornoš, L.; Šilha, J.

    2014-07-01

    The small Near-Earth Asteroids (NEAs) represent a potential risk but also an easily accessible space resource for future robotic or human in-situ space exploration or commercial activities. However, the population of 1--300 m NEAs is not well understood in terms of size- frequency and orbital distribution. NEAs with diameters below 200 m tend to have much faster spin rates than large objects and they are believed to be monolithic and not rubble-pile like their large counterparts. Moreover, the current surveys do not systematically search for the small NEAs that are mostly overlooked. We propose a low- cost robotic optical survey (ADAM-WFS) aimed at small NEAs based on four state-of-the-art telescopes having extremely wide fields of view. The four Houghton-Terebizh 30-cm astrographs (Fig. left) with 4096×4096 -pixel CCD cameras will acquire 96 square degrees in one exposure with the plate scale of 4.4 arcsec/pixel. In 30 seconds, the system will be able to reach +17.5 mag in unfiltered mode. The survey will be operated on semi-automatic basis, covering the entire night sky three times per night and optimized toward fast moving targets recognition. The advantage of the proposed system is the usage of existing of-the-shelf components and software for the image processing and object identification and linking (Denneau et al., 2013). The one-year simulation of the survey (Fig. right) at the testing location at AGO Modra observatory in Slovakia revealed that we will detect 60--240 NEAs between 1--300 m that get closer than 10 lunar distances from the Earth. The number of detections will rise by a factor of 1.5--2 in case the survey is placed at a superb observing location such as Canary Islands. The survey will also serve as an impact warning system for imminent impactors. Our simulation showed that we have a 20 % chance of finding a 50-m NEA on a direct impact orbit. The survey will provide multiple byproducts from the all-sky scans, such as comet discoveries, sparse

  9. Making light work: illuminating the future of biomedical optics.

    PubMed

    Elwell, Clare E; Cooper, Chris E

    2011-11-28

    In 1996, the Royal Society held a Discussion Meeting entitled 'Near-infrared spectroscopy and imaging of living systems'. In 2010, this topic was revisited in a Theo Murphy Royal Society Scientific Discussion Meeting entitled 'Making light work: illuminating the future of biomedical optics'. The second meeting provided the opportunity for leading researchers to reflect on how the technology, methods and applications have evolved over the past 14 years and assess where they have made a major impact. Particular emphasis was placed on discussions of future prospects and associated challenges. This Introduction provides an overview of the state of the art of near-infrared spectroscopy (NIRS) and biomedical optics, with specific reference to the contributed papers from the invited speakers included in this issue. Importantly, we also reflect on the contributions from all of the attendees by highlighting the issues raised during oral presentations, facilitated panel sessions and discussions, and use these to summarize the current opinion on the development and application of optical systems for use in the clinical and life sciences. A notable outcome from the meeting was a plan to establish a biennial international conference for developers and users of NIRS technologies.

  10. A fast, wide field of view, catadioptric telescope for Whipple

    NASA Astrophysics Data System (ADS)

    McGuire, James P.

    2014-12-01

    We describe the optical design of a spaceborne f/1.3 catadioptric telescope with a 9 degree field and 77 cm aperture that is being proposed to study objects in the Kuiper belt, Sedna Region, and Oort cloud.

  11. Three-Dimensional Resolution Doubling in Wide-Field Fluorescence Microscopy by Structured Illumination

    PubMed Central

    Gustafsson, Mats G. L.; Shao, Lin; Carlton, Peter M.; Wang, C. J. Rachel; Golubovskaya, Inna N.; Cande, W. Zacheus; Agard, David A.; Sedat, John W.

    2008-01-01

    Structured illumination microscopy is a method that can increase the spatial resolution of wide-field fluorescence microscopy beyond its classical limit by using spatially structured illumination light. Here we describe how this method can be applied in three dimensions to double the axial as well as the lateral resolution, with true optical sectioning. A grating is used to generate three mutually coherent light beams, which interfere in the specimen to form an illumination pattern that varies both laterally and axially. The spatially structured excitation intensity causes normally unreachable high-resolution information to become encoded into the observed images through spatial frequency mixing. This new information is computationally extracted and used to generate a three-dimensional reconstruction with twice as high resolution, in all three dimensions, as is possible in a conventional wide-field microscope. The method has been demonstrated on both test objects and biological specimens, and has produced the first light microscopy images of the synaptonemal complex in which the lateral elements are clearly resolved. PMID:18326650

  12. Prototyping results for a wide-field fiber positioner for the Giant Segmented Mirror Telescope

    NASA Astrophysics Data System (ADS)

    Moore, Anna M.; McGrath, Andrew J.

    2004-07-01

    Given the physical size of the GSMT prime focus field is approximately equivalent to that of the Subaru telescope it is possible to directly apply current technology developed for the Fiber Multi-Object Spectrograph instrument (FMOS, to be commissioned in 2005) and substantially reduce the risk associated with developing a new solution for wide-field multi-object spectroscopy on an ELT. The Anglo-Australian Observatory has recently completed a design study for an ~1000 fiber, Echidna-style positioner for the prime focus of the Giant Segmented Mirror Telescope (GSMT). The positioner forms part of the wide-field Multi-Object Multi-Fiber Optical Spectrograph (MOMFOS), an ELT prime focus instrument offering a minimum of 800 fibers patrolling the corrected 20 arcmin field. The design study identified 2 components of an equivalent MOMFOS positioner design that required prototyping. Firstly, a higher spine packing density is required to satisfy the proposed scientific program. Secondly, the fiber position measurement system adopted for FMOS cannot be simply scaled and applied to MOMFOS given space constraints in the top end unit. As such a new and, if possible, simpler system was required. Prototyping results for both components are presented.

  13. Fundamental study of flow field generated by rotorcraft blades using wide-field shadowgraph

    NASA Technical Reports Server (NTRS)

    Parthasarathy, S. P.; Cho, Y. I.; Back, L. H.

    1985-01-01

    The vortex trajectory and vortex wake generated by helicopter rotors are visualized using a wide-field shadowgraph technique. Use of a retro-reflective Scotchlite screen makes it possible to investigate the flow field generated by full-scale rotors. Tip vortex trajectories are visible in shadowgraphs for a range of tip Mach number of 0.38 to 0.60. The effect of the angle of attack is substantial. At an angle of attack greater than 8 degrees, the visibility of the vortex core is significant even at relatively low tip Mach numbers. The theoretical analysis of the sensitivity is carried out for a rotating blade. This analysis demonstrates that the sensitivity decreases with increasing dimensionless core radius and increases with increasing tip Mach number. The threshold value of the sensitivity is found to be 0.0015, below which the vortex core is not visible and above which it is visible. The effect of the optical path length is also discussed. Based on this investigation, it is concluded that the application of this wide-field shadowgraph technique to a large wind tunnel test should be feasible. In addition, two simultaneous shadowgraph views would allow three-dimensional reconstruction of vortex trajectories.

  14. Lensless wide-field fluorescent imaging on a chip using compressive decoding of sparse objects.

    PubMed

    Coskun, Ahmet F; Sencan, Ikbal; Su, Ting-Wei; Ozcan, Aydogan

    2010-05-10

    We demonstrate the use of a compressive sampling algorithm for on-chip fluorescent imaging of sparse objects over an ultra-large field-of-view (>8 cm(2)) without the need for any lenses or mechanical scanning. In this lensfree imaging technique, fluorescent samples placed on a chip are excited through a prism interface, where the pump light is filtered out by total internal reflection after exciting the entire sample volume. The emitted fluorescent light from the specimen is collected through an on-chip fiber-optic faceplate and is delivered to a wide field-of-view opto-electronic sensor array for lensless recording of fluorescent spots corresponding to the samples. A compressive sampling based optimization algorithm is then used to rapidly reconstruct the sparse distribution of fluorescent sources to achieve approximately 10 microm spatial resolution over the entire active region of the sensor-array, i.e., over an imaging field-of-view of >8 cm(2). Such a wide-field lensless fluorescent imaging platform could especially be significant for high-throughput imaging cytometry, rare cell analysis, as well as for micro-array research.

  15. Wide field OCT based microangiography in living human eye (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Zhang, Qinqin; Chen, Chieh-Li; Chu, Zhongdi; Zhang, Anqi; An, Lin; Durbin, Mary; Sharma, Utkarsh; Rosenfeld, Philip J.; Wang, Ruikang K.

    2016-03-01

    To investigate the application of optical microangiography (OMAG) in living human eye. Patients with different macular diseases were recruited, including diabetic retinopathy (DR), geographic atrophy (GA), retinitis pigmentosa (RP), and venous occlusion, et al. Wide field OCT angiography images can be generated by montage scanning protocol based on the tracking system. OMAG algorithm based on complex differentiation was used to extract the blood flow and removed the bulk motion by 2D cross-correlation method. The 3D angiography was segmented into 3 layers in the retina and 2 layers in the choroid. The en-face maximum projection was used to obtain 2-dimensional angiograms of different layers coded with different colors. Flow and structure images were combined for cross-sectional view. En face OMAG images of different macular diseases showed a great agreement with FA. Meanwhile, OMAG gave more distinct vascular network visions that were less affected by hemorrhage and leakage. The MAs were observed in both superficial and middle retinal layers based on OMAG angiograms in different layers of DR patients. The contour line of FAZ was extracted as well, which can be quantitative the retinal diseases. For GA patient, the damage of RPE layer enhanced the penetration of light and enabled the acquisition of choriocapillaries and choroidal vessels. The wide field OMAG angiogram enabled the capability of capturing the entire geographic atrophy. OMAG provides depth-resolved information and detailed vascular images of DR and GA patients, providing a better visualization of vascular network compared to FA.

  16. Electrowetting liquid lens array on curved substrates for wide field of view image sensor

    NASA Astrophysics Data System (ADS)

    Bang, Yousung; Lee, Muyoung; Won, Yong Hyub

    2016-03-01

    In this research, electrowetting liquid lens array on curved substrates is developed for wide field of view image sensor. In the conventional image sensing system, this lens array is usually in the form of solid state. However, in this state, the lens array which is similar to insect-like compound eyes in nature has several limitations such as degradation of image quality and narrow field of view because it cannot adjust focal length of lens. For implementation of the more enhanced system, the curved array of lenses based on electrowetting effect is developed in this paper, which can adjust focal length of lens. The fabrication of curved lens array is conducted upon the several steps, including chamber fabrication, electrode & dielectric layer deposition, liquid injection, and encapsulation. As constituent materials, IZO coated convex glass, UV epoxy (NOA 68), DI water, and dodecane are used. The number of lenses on the fabricated panel is 23 by 23 and each lens has 1mm aperture with 1.6mm pitch between adjacent lenses. When the voltage is applied on the device, it is observed that each lens is changed from concave state to convex state. From the unique optical characteristics of curved array of liquid lenses such as controllable focal length and wide field of view, we can expect that it has potential applications in various fields such as medical diagnostics, surveillance systems, and light field photography.

  17. Confirmation of Wide-field Signatures in Redshifted 21 cm Power Spectra

    NASA Astrophysics Data System (ADS)

    Thyagarajan, Nithyanandan; Jacobs, Daniel C.; Bowman, Judd D.; Barry, N.; Beardsley, A. P.; Bernardi, G.; Briggs, F.; Cappallo, R. J.; Carroll, P.; Deshpande, A. A.; de Oliveira-Costa, A.; Dillon, Joshua S.; Ewall-Wice, A.; Feng, L.; Greenhill, L. J.; Hazelton, B. J.; Hernquist, L.; Hewitt, J. N.; Hurley-Walker, N.; Johnston-Hollitt, M.; Kaplan, D. L.; Kim, Han-Seek; Kittiwisit, P.; Lenc, E.; Line, J.; Loeb, A.; Lonsdale, C. J.; McKinley, B.; McWhirter, S. R.; Mitchell, D. A.; Morales, M. F.; Morgan, E.; Neben, A. R.; Oberoi, D.; Offringa, A. R.; Ord, S. M.; Paul, Sourabh; Pindor, B.; Pober, J. C.; Prabu, T.; Procopio, P.; Riding, J.; Udaya Shankar, N.; Sethi, Shiv K.; Srivani, K. S.; Subrahmanyan, R.; Sullivan, I. S.; Tegmark, M.; Tingay, S. J.; Trott, C. M.; Wayth, R. B.; Webster, R. L.; Williams, A.; Williams, C. L.; Wyithe, J. S. B.

    2015-07-01

    We confirm our recent prediction of the “pitchfork” foreground signature in power spectra of high-redshift 21 cm measurements where the interferometer is sensitive to large-scale structure on all baselines. This is due to the inherent response of a wide-field instrument and is characterized by enhanced power from foreground emission in Fourier modes adjacent to those considered to be the most sensitive to the cosmological H i signal. In our recent paper, many signatures from the simulation that predicted this feature were validated against Murchison Widefield Array (MWA) data, but this key pitchfork signature was close to the noise level. In this paper, we improve the data sensitivity through the coherent averaging of 12 independent snapshots with identical instrument settings and provide the first confirmation of the prediction with a signal-to-noise ratio \\gt 10. This wide-field effect can be mitigated by careful antenna designs that suppress sensitivity near the horizon. Simple models for antenna apertures that have been proposed for future instruments such as the Hydrogen Epoch of Reionization Array and the Square Kilometre Array indicate they should suppress foreground leakage from the pitchfork by ∼40 dB relative to the MWA and significantly increase the likelihood of cosmological signal detection in these critical Fourier modes in the three-dimensional power spectrum.

  18. Water-Immersible MEMS scanning mirror designed for wide-field fast-scanning photoacoustic microscopy

    NASA Astrophysics Data System (ADS)

    Yao, Junjie; Huang, Chih-Hsien; Martel, Catherine; Maslov, Konstantin I.; Wang, Lidai; Yang, Joon-Mo; Gao, Liang; Randolph, Gwendalyn; Zou, Jun; Wang, Lihong V.

    2013-03-01

    By offering images with high spatial resolution and unique optical absorption contrast, optical-resolution photoacoustic microscopy (OR-PAM) has gained increasing attention in biomedical research. Recent developments in OR-PAM have improved its imaging speed, but have sacrificed either the detection sensitivity or field of view or both. We have developed a wide-field fast-scanning OR-PAM by using a water-immersible MEMS scanning mirror (MEMS-ORPAM). Made of silicon with a gold coating, the MEMS mirror plate can reflect both optical and acoustic beams. Because it uses an electromagnetic driving force, the whole MEMS scanning system can be submerged in water. In MEMS-ORPAM, the optical and acoustic beams are confocally configured and simultaneously steered, which ensures uniform detection sensitivity. A B-scan imaging speed as high as 400 Hz can be achieved over a 3 mm scanning range. A diffraction-limited lateral resolution of 2.4 μm in water and a maximum imaging depth of 1.1 mm in soft tissue have been experimentally determined. Using the system, we imaged the flow dynamics of both red blood cells and carbon particles in a mouse ear in vivo. By using Evans blue dye as the contrast agent, we also imaged the flow dynamics of lymphatic vessels in a mouse tail in vivo. The results show that MEMS-OR-PAM could be a powerful tool for studying highly dynamic and time-sensitive biological phenomena.

  19. Wide field of view laser beacon system for three-dimensional aircraft position measurement

    NASA Technical Reports Server (NTRS)

    Sweet, L. M.; Miles, R. B.; Webb, S. G.; Wong, E. Y.

    1981-01-01

    This paper presents a new wide field of view laser beacon system for measurement, in three dimensions, of aircraft or other remote objects. The system is developed for aircraft collision hazard warning independent of ground-based hardware, as well as for flight research, helicopter-assisted construction and rescue, and robotic manipulation applications. Accurate information describing the relative range, elevation, and azimuth of the aircraft are generated by the sweep of a low-power fan-shaped rotating laser beacon past an array of optical detectors. The system achieves a wide angle of acceptance of laser beacon light through use of compound parabolic concentrators, which collimate the light for spectral filtering to minimize solar interference. An on-board microprocessor system converts the pulse sequence to aircraft position in real time. System reliability and performance are enhanced through narrow pass filtering of the pulse signals, digital logic design to mask spurious signals, and adaptive modulation of trigger threshold levels.

  20. Sampling and Analysis of Impact Crater Residues Found on the Wide Field Planetary Camera-2 Radiator

    NASA Technical Reports Server (NTRS)

    Kearsley, A. T.; Grime, G. W.; Colaux, J. L.; Jeynes, C.; Palitsin, V. V.; Webb, R, P.; Griffin, T. J.; Reed, B. B.; Anz-Meador, P. D.; Kou, J.-C.; Robinson, G. A.; Opiela, J. N.; Gerlach, L.

    2013-01-01

    After nearly 16 years in low Earth orbit (LEO), the Wide Field Planetary Camera-2 (WFPC2) was recovered from the Hubble Space Telescope (HST) in May 2009, during the 12 day shuttle mission designated STS-125. The WFPC-2 radiator had been struck by approximately 700 impactors producing crater features 300 microns and larger in size. Following optical inspection in 2009, agreement was reached for joint NASA-ESA study of crater residues, in 2011. Over 480 impact features were extracted at NASA Johnson Space Center's (JSC) Space Exposed Hardware clean-room and curation facility during 2012, and were shared between NASA and ESA. We describe analyses conducted using scanning electron microscopy (SEM) - energy dispersive X-ray spectrometry (EDX): by NASA at JSC's Astromaterials Research and Exploration Science (ARES) Division; and for ESA at the Natural History Museum (NHM), with Ion beam analysis (IBA) using a scanned proton microbeam at the University of Surrey Ion Beam Centre (IBC).

  1. Meteor observations with Mini-Mega-TORTORA wide-field monitoring system

    NASA Astrophysics Data System (ADS)

    Karpov, S.; Orekhova, N.; Beskin, G.; Biryukov, A.; Bondar, S.; Ivanov, E.; Katkova, E.; Perkov, A.; Sasyuk, V.

    2016-12-01

    Here we report on the results of meteor observations with 9-channel Mini-Mega-TORTORA (MMT-9) optical monitoring system with the wide field and high temporal resolution. During the first 1.5 years of operation more than 90 thousands of meteors have been detected, at a rate of 300-350 per night, with durations from 0.1 to 2.5 seconds and angular velocities up to 38 degrees per second. The faintest detected meteors have peak brightnesses about 10 mag, while the majority have them ranging from 4 to 8 mag. Some of the meteors have been observed in BVR filters simultaneously. Color variations along the trail for them have been determined. The parameters of the detected meteors have been published online. The database also includes data from 10 thousands of meteors detected by our previous FAVOR camera during 2006-2009.

  2. WISPIR: A Wide-Field Imaging SPectrograph for the InfraRed for the SPICA Observatory

    NASA Technical Reports Server (NTRS)

    Benford, Dominic J.; Mundy, Lee G.

    2010-01-01

    We have undertaken a study of a far infrared imaging spectrometer based on a Fourier transform spectrometer that uses well-understood, high maturity optics, cryogenics, and detectors to further our knowledge of the chemical and astrophysical evolution of the Universe as it formed planets, stars, and the variety of galaxy morphologies that we observe today. The instrument, Wide-field Imaging Spectrometer for the InfraRed (WISPIR), would operate on the SPICA observatory, and will feature a spectral range from 35 - 210 microns and a spectral resolving power of R=1,000 to 6,000, depending on wavelength. WISPIR provides a choice of full-field spectral imaging over a 2'x2' field or long-slit spectral imaging along a 2' slit for studies of astrophysical structures in the local and high-redshift Universe. WISPIR in long-slit mode will attain a sensitivity two orders of magnitude better than what is currently available.

  3. Quantitative microscopy and nanoscopy of sickle red blood cells performed by wide field digital interferometry

    NASA Astrophysics Data System (ADS)

    Shaked, Natan T.; Satterwhite, Lisa L.; Telen, Marilyn J.; Truskey, George A.; Wax, Adam

    2011-03-01

    We have applied wide-field digital interferometry (WFDI) to examine the morphology and dynamics of live red blood cells (RBCs) from individuals who suffer from sickle cell anemia (SCA), a genetic disorder that affects the structure and mechanical properties of RBCs. WFDI is a noncontact, label-free optical microscopy approach that can yield quantitative thickness profiles of RBCs and measurements of their membrane fluctuations at the nanometer scale reflecting their stiffness. We find that RBCs from individuals with SCA are significantly stiffer than those from a healthy control. Moreover, we show that the technique is sensitive enough to distinguish classes of RBCs in SCA, including sickle RBCs with apparently normal morphology, compared to the stiffer crescent-shaped sickle RBCs. We expect that this approach will be useful for diagnosis of SCA and for determining efficacy of therapeutic agents.

  4. A wide-field infrared camera for the Observatoire du mont Mégantic

    NASA Astrophysics Data System (ADS)

    Artigau, Etienne; Doyon, Rene; Nadeau, Daniel; Vallee, Philippe; Thibault, Simon

    2003-03-01

    A wide-field near-infrared (0.8 2.4 μm) camera for the 1.6 m telescope of the Observatoire du mont Mégantic (OMM), is currently under construction at the Université de Montréal. The field of view is 30' × 30' and will have very little distortion. The optics comprise 8 spherical cryogenic lenses. The instrument features two filter wheels with provision for 10 filters including broad band I, z, J, H, K and other narrow-band filters. The camera is based on a 2048 × 2048 HgCdTe Hawaii-2 detector driven by a 32-output SDSU-II controller operating at ~250 kHz.

  5. Sampling and Analysis of Impact Crater Residues Found on the Wide Field Planetary Camera-2 Radiator

    NASA Astrophysics Data System (ADS)

    Anz-Meador, P. D.; Liou, J.-C.; Ross, D.; Robinson, G. A.; Opiela, J. N.; Kearsley, A. T.; Grime, G. W.; Colaux, J. L.; Jeynes, C.; Palitsin, V. V.; Webb, R. P.; Griffin, T. J.; Reed, B. B.; Gerlach, L.

    2013-08-01

    After nearly 16 years in low Earth orbit (LEO), the Wide Field Planetary Camera-2 (WFPC2) was recovered from the Hubble Space Telescope (HST) in May 2009, during the 12 day shuttle mission designated STS-125. The WFPC-2 radiator had been struck by approximately 700 impactors producing crater features 300 μ m and larger in size. Following optical inspection in 2009, agreement was reached for joint NASA-ESA study of crater residues, in 2011. Over 480 impact features were extracted at NASA Johnson Space Center's (JSC) Space Exposed Hardware clean-room and curation facility during 2012, and were shared between NASA and ESA. We describe analyses conducted using scanning electron microscopy (SEM) - energy dispersive X-ray spectrometry (EDX): by NASA at JSC's Astromaterials Research and Exploration Science (ARES) Division; and for ESA at the Natural History Museum (NHM), with Ion beam analysis (IBA) using a scanned proton microbeam at the University of Surrey Ion Beam Centre (IBC).

  6. Micrometeoroid Impacts on the Hubble Space Telescope Wide Field and Planetary Camera 2: Smaller Particle Impacts

    NASA Technical Reports Server (NTRS)

    Ross, D. K.; Anz-Meador, P.; Liou, J.C.; Opiela, J.; Kearsley, A. T.; Grime, G.; Webb, R.; Jeynes, C.; Palitsin, V.; Colaux, J.; Griffin, T.; Gerlach, L.; Wozniakiewicz, P. J.; Price, M. C.; Burchell, M. J.; Cole, M. J.

    2014-01-01

    The radiator shield on the Wide Field and Planetary Camera 2 (WFPC2) was subject to optical inspection following return from the Hubble Space Telescope (HST) in 2009. The survey revealed over 600 impact features of > 300 micrometers diameter, from exposure in space for 16 years. Subsequently, an international collaborative programme of analysis was organized to determine the origin of hypervelocity particles responsible for the damage. Here we describe examples of the numerous smaller micrometeoroid (MM) impact features (< 700 micrometers diameter) which excavated zinc orthotitanate (ZOT) paint from the radiator surface, but did not incorporate material from underlying Al alloy; larger impacts are described by [3]. We discuss recognition and interpretation of impactor remains, and MM compositions found on WFPC2.

  7. Speckle correlation resolution enhancement of wide-field fluorescence imaging (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Yilmaz, Hasan

    2016-03-01

    Structured illumination enables high-resolution fluorescence imaging of nanostructures [1]. We demonstrate a new high-resolution fluorescence imaging method that uses a scattering layer with a high-index substrate as a solid immersion lens [2]. Random scattering of coherent light enables a speckle pattern with a very fine structure that illuminates the fluorescent nanospheres on the back surface of the high-index substrate. The speckle pattern is raster-scanned over the fluorescent nanospheres using a speckle correlation effect known as the optical memory effect. A series of standard-resolution fluorescence images per each speckle pattern displacement are recorded by an electron-multiplying CCD camera using a commercial microscope objective. We have developed a new phase-retrieval algorithm to reconstruct a high-resolution, wide-field image from several standard-resolution wide-field images. We have introduced phase information of Fourier components of standard-resolution images as a new constraint in our algorithm which discards ambiguities therefore ensures convergence to a unique solution. We demonstrate two-dimensional fluorescence images of a collection of nanospheres with a deconvolved Abbe resolution of 116 nm and a field of view of 10 µm × 10 µm. Our method is robust against optical aberrations and stage drifts, therefore excellent for imaging nanostructures under ambient conditions. [1] M. G. L. Gustafsson, J. Microsc. 198, 82-87 (2000). [2] H. Yilmaz, E. G. van Putten, J. Bertolotti, A. Lagendijk, W. L. Vos, and A. P. Mosk, Optica 2, 424-429 (2015).

  8. Treatment strategies for inherited optic neuropathies: past, present and future.

    PubMed

    Yu-Wai-Man, P; Votruba, M; Moore, A T; Chinnery, P F

    2014-05-01

    Bilateral visual loss secondary to inherited optic neuropathies is an important cause of registrable blindness among children and young adults. The two prototypal disorders seen in clinical practice are Leber hereditary optic neuropathy (LHON) and autosomal dominant optic atrophy (DOA). About 90% of LHON cases are due to one of three mitochondrial DNA (mtDNA) point mutations: m.3460G>A, m.11778G>A, and m.14484T>C, which affect critical complex I subunits of the mitochondrial respiratory chain. The majority of patients with DOA harbour pathogenic mutations within OPA1, a nuclear gene that codes for a multifunctional inner mitochondrial membrane protein. Despite their contrasting genetic basis, LHON and DOA share overlapping pathological and clinical features that serve to highlight the striking tissue-specific vulnerability of the retinal ganglion cell (RGC) layer to disturbed mitochondrial function. In addition to severe visual loss secondary to progressive optic nerve degeneration, a subgroup of patients will also develop a more aggressive syndromic phenotype marked by significant neurological deficits. The management of LHON and DOA remains largely supportive, but major advances in our understanding of the mechanisms underpinning RGC loss in these two disorders are paving the way for novel forms of treatment aimed at halting or reversing visual deterioration at different stages of the disease process. In addition to neuroprotective strategies for rescuing RGCs from irreversible cell death, innovative in vitro fertilisation techniques are providing the tantalising prospect of preventing the germline transmission of pathogenic mtDNA mutations, eradicating in so doing the risk of disease in future generations.

  9. Single-acquisition wide-field superresolution for telescopes.

    PubMed

    Wereley, Steve; Zhang, Yuxing; Khor, Jian-Wei; Snoeyink, Craig

    2016-12-10

    A simple optical setup is introduced here that is capable of improving the diffraction-limited angular resolution of a telescope at minimal cost to image quality. The system consists of, at minimum, an axicon and a convex lens located in the optical path of the telescope, which can increase the angular resolution by up to 38%. Analytical results for this resolution gain along with the Strehl ratio of this system are presented along with experimental results, which show a 30% improvement in single-acquisition image resolution with a Strehl ratio of 0.07, agreeing well with predicted values. With an ultrashallow axicon, large increases in Strehl ratio are possible, up to and beyond unity making higher angular resolution measurements possible with little cost to image quality or experimental complexity.

  10. Lessons Learned from the Wide Field Camera 3 TV1 Test Campaign and Correlation Effort

    NASA Technical Reports Server (NTRS)

    Peabody, Hume; Stavley, Richard; Bast, William

    2007-01-01

    In January 2004, shortly after the Columbia accident, future servicing missions to the Hubble Space Telescope (HST) were cancelled. In response to this, further work on the Wide Field Camera 3 instrument was ceased. Given the maturity level of the design, a characterization thermal test (TV1) was completed in case the mission was re-instated or an alternate mission found on which to fly the instrument. This thermal test yielded some valuable lessons learned with respect to testing configurations and modeling/correlation practices, including: 1. Ensure that the thermal design can be tested 2. Ensure that the model has sufficient detail for accurate predictions 3. Ensure that the power associated with all active control devices is predicted 4. Avoid unit changes for existing models. This paper documents the difficulties presented when these recommendations were not followed.

  11. Tomographic control for wide field AO systems on extremely large telescopes

    NASA Astrophysics Data System (ADS)

    Petit, C.; Conan, J.-M.; Fusco, T.; Neichel, B.

    2010-07-01

    We investigate in this article tomographic control using both Laser and Natural Guide Stars (LGS and NGS) in the particular framework of the European Extremely Large Telescope (E-ELT) Wide Field Adaptive Optics (WFAO) modules design. A similar global control strategy has been indeed derived for both the Laser Tomographic Adaptive Optics (LTAO) and Multi-Conjugate Adaptive Optics (MCAO) modules of the E-ELT, due to similar constraints. This control strategy leads in both cases to a split control of low order modes measured thanks to NGS and high order modes measured thanks to LGS. We investigate here this split tomographic control, compared to an optimal coupled solution. To support our analysis, a dedicated simulation code has been developed. Indeed, due to the huge complexity of the EELT, fast simulation tools must be considered to explore quickly the tomographic issues. We describe our control strategy which has lead to considering split tomographic control. First results on Tomography for E-ELT WFAO systems are then presented and discussed.

  12. Large filters for wide-field survey telescope LSST

    NASA Astrophysics Data System (ADS)

    Morgado, Nazario; Pinard, Laurent; Sassolas, Benoit; Flaminio, Raffaele; Forest, Daniéle; Lagrange, Bernard; Michel, Christophe; Antilogus, Pierre

    2012-09-01

    The LSST design foresees the use of six wide-band large optical filters that can alternatively be moved in front of the CCD camera. Each of the six filters has a different band-pass covering all the wavelengths from 300 nm to 1200 nm. The way to achieve this is to coat an optimized optical thin films stack on a filter substrate. Each filter requires a specific design using specific appropriate materials. The main characteristics of these filters, that constitute a real technological challenge, are: their relatively large size - their radii of curvature (about 5.6 m) that represent a sagitta of 12,5 mm that increases the uniformity complexity, the large rejection band requirements with transmission lower than 0.01 % out of the band and a transmission of 95 % over the band-pass. This paper proposes to show the problematic and the results obtained at LMA (Laboratoire des Matériaux Avancés-FRANCE) to the purpose of realizing these filters using the IBS (Ion Beam Sputtering) deposition technique. The results obtained with High-Pass/Low-Pass structures will be presented. Experimental results will be shown concerning the R-band filter (552-691 nm). An overview of the work to be done to realize transmittance map over large filters will be given.

  13. Improving the performances of current optical interferometers & future designs

    NASA Astrophysics Data System (ADS)

    Arnold, L.; Le Coroller, H.; Surdej, J.

    2014-04-01

    The number of astrophysical studies making use of interferometers has steadily increased during the past 15 years. Nevertheless, the performances of interferometers are still limited: their sensitivity does not exceed magnitude V=12, and their imaging capability could yet be improved by increasing the number of telescopes/sub-apertures. In the context of the ELTs, it is not certain how future interferometry projects will be financed. However, interferometry remains the only way to observe compact astrophysical objects at very high angular resolution (< milli-arcsecond), like gravitational micro-lensing events, central engines of AGNs, proto-planetary disks, exoplanets, etc. The aim of this workshop was to review and discuss the development of technologies that could improve the performances of current and future interferometers: new optical designs; techniques to improve the accuracy of measurements (visibility, closure-phase, etc.); progress on delay-line performances; solutions without delay-lines; technologies for larger apertures at lower cost (ex: lightweight replica mirrors); optimized beam combiners (integrated optic, pupil densifier, etc.); fringe tracking systems; laser telemetry applied to interferometry; heterodyne interferometry; progress in heterodyne detection using new technologies (laser comb, time propagation technologies, etc.); progress in image reconstruction techniques; progress in nulling interferometry; and important science cases that could benefit from progress in interferometry (report of observations at the limit of current interferometers). Nearly 50 oral presentations have been delivered, followed by very lively discussions which eventually emerged with the proposition to organize the "Planet Formation Interferometer/Imager" (PFI) project. The present proceedings reflect most of the highlights of this international colloquium.

  14. Fast and compact wide-field Gregorian telescope

    NASA Astrophysics Data System (ADS)

    Bahrami, Mehdi; Goncharov, Alexander V.

    2012-09-01

    A traditional Gregorian telescope features an intermediate focus, which makes the system longer than an equivalent fnumber Cassegrain design. One could shorten the Gregorian system by inserting a flat mirror before the secondary mirror. We explore the potential of this compact configuration for sky survey imaging with relaxed requirements for angular resolution. A 0.5 m f/1.4 telescope with 4 deg full field is presented. The modified design consists of two elliptical mirrors and a folding flat in between. A plano-convex field flattener is used near the focal plane. The telescope optical performance is analyzed and possible improvements are discussed based on aberration balancing. A special emphasis is given to stay light analysis and baffle designs are considered.

  15. Future electro-optical sensors and processing in urban operations

    NASA Astrophysics Data System (ADS)

    Grönwall, Christina; Schwering, Piet B.; Rantakokko, Jouni; Benoist, Koen W.; Kemp, Rob A. W.; Steinvall, Ove; Letalick, Dietmar; Björkert, Stefan

    2013-10-01

    In the electro-optical sensors and processing in urban operations (ESUO) study we pave the way for the European Defence Agency (EDA) group of Electro-Optics experts (IAP03) for a common understanding of the optimal distribution of processing functions between the different platforms. Combinations of local, distributed and centralized processing are proposed. In this way one can match processing functionality to the required power, and available communication systems data rates, to obtain the desired reaction times. In the study, three priority scenarios were defined. For these scenarios, present-day and future sensors and signal processing technologies were studied. The priority scenarios were camp protection, patrol and house search. A method for analyzing information quality in single and multi-sensor systems has been applied. A method for estimating reaction times for transmission of data through the chain of command has been proposed and used. These methods are documented and can be used to modify scenarios, or be applied to other scenarios. Present day data processing is organized mainly locally. Very limited exchange of information with other platforms is present; this is performed mainly at a high information level. Main issues that arose from the analysis of present-day systems and methodology are the slow reaction time due to the limited field of view of present-day sensors and the lack of robust automated processing. Efficient handover schemes between wide and narrow field of view sensors may however reduce the delay times. The main effort in the study was in forecasting the signal processing of EO-sensors in the next ten to twenty years. Distributed processing is proposed between hand-held and vehicle based sensors. This can be accompanied by cloud processing on board several vehicles. Additionally, to perform sensor fusion on sensor data originating from different platforms, and making full use of UAV imagery, a combination of distributed and

  16. Deep wide-field imaging of main belt comets and asteroids

    NASA Astrophysics Data System (ADS)

    Rajagopal, Jayadev; Jewitt, David; Ridgway, Susan

    2014-02-01

    We propose to continue a deep imaging study, using the pODI optical imager on the WIYN telescope, of selected regions of the main asteroid belt that contain a known main-belt comet (MBC). An MBC is an asteroid that shows evidence of significant mass loss, seen as transient, comet- like tails and comae. In 2013, we were awarded 4 nights over the two semesters and obtained high-impact wide-field, deep images of two new MBCs, P/2010 A2 and P/2013 P5, to study their origins. In addition, we use the considerable pODI field-of-view to search for direct evidence of very low-level mass-loss activity in the sample of main belt asteroids that will also be detected. Asteroids could be repositories of primordial water and a supply for volatiles on earth. In order to test this possibility (suggested by the recent TALCS asteroid survey at CFHT) and further characterize the mass-loss in known MBC activity, we will observe ~ 25- arcminute fields around ~ 3 known MBCs to significantly deeper levels than TALCS with better resolution. More than half of the 2013A allocation was lost to weather. We request 4 nights in 2014A. With this additional time we are confident of reaching publishable results on low level mass-loss and on the evolution of the activity in known MBCs. We will follow the secular evolution of P/2010 A2. And, as in the previous two semesters, we hope to add a spectacular wide-field deep image of a new MBC.

  17. The development of a wide-field, high-resolution UV Raman hyperspectral imager

    NASA Astrophysics Data System (ADS)

    Gomer, Nathaniel R.; Nelson, Matthew P.; Angel, S. M.

    2015-05-01

    Raman spectroscopy is a valuable tool for the investigation and analysis of explosive and biological analytes because it provides a unique molecular fingerprint that allows for unambiguous target identification. Raman can be advantageous when utilized with deep UV excitation, but typical deep UV Raman systems have numerous limitations that hinder their performance and make their potential integration onto a field portable platform difficult. These systems typically offer very low throughput, are physically large and heavy, and can only probe an area the size of a tightly focused laser, severely diminishing the ability of the system to investigate large areas efficiently. The majority of these limitations are directly related to a system's spectrometer, which is typically dispersive grating based and requires a very narrow slit width and long focal length optics to achieve high spectral resolution. To address these shortcomings, ChemImage Sensor Systems (CISS), teaming with the University of South Carolina, are developing a revolutionary wide-field Raman hyperspectral imaging system capable of providing wide-area, high resolution measurements with greatly increased throughput in a small form factor, which would revolutionize the way Raman is conducted and applied. The innovation couples a spatial heterodyne spectrometer (SHS), a novel slit-less spectrometer that operates similar to Michelson interferometer, with a fiber array spectral translator (FAST) fiber array, a two-dimensional imaging fiber for hyperspectral imagery. This combination of technologies creates a novel wide-field, high throughput Raman hyperspectral imager capable of yielding very high spectral resolution measurements using defocused excitation, giving the system a greater area coverage and faster search rate than traditional Raman systems. This paper will focus on the need for an innovative UV Raman system, provide an overview of spatial heterodyne Raman spectroscopy, and discuss the development

  18. A purely reflective large wide-field telescope

    NASA Astrophysics Data System (ADS)

    Terebizh, V. Yu.

    2008-06-01

    Two versions of a fast, purely reflective Paul-Baker-type telescope are discussed, each with an 8.4-m aperture, 3° diameter flat field and f/1.25 focal ratio. The first version is based on a common, even asphere type of surface with zero conic constant. The primary and tertiary mirrors are 6th order aspheres, while the secondary mirror is an 8th order asphere (referred to here for brevity, as the 6/8/6 configuration). The D 80 diameter of a star image varies from 0″.18 on the optical axis up to 0″.27 at the edge of the field (9.3-13.5 μm). The second version of the telescope is based on a polysag surface type, which uses a polynomial expansion in the sag z, r^2 = 2R_0 z - left( {1 + b} right)z^2 + a_3 z^3 + a_4 z^3 + a_4 z^4 + ldots + a_N z^N instead of the common form of aspheric surface. This approach results in somewhat better images, with D 80 ranging from 0″.16 to 0″.23, using a lower-order 3/4/3 combination of powers for the mirror surfaces. An additional example with 3.5-m aperture, 3°.5 diameter flat field, and f/1.25 focal ratio featuring near-diffraction-limited image quality is also presented.

  19. Wide-field Raman imaging for bone detection in tissue

    PubMed Central

    Papour, Asael; Kwak, Jin Hee; Taylor, Zach; Wu, Benjamin; Stafsudd, Oscar; Grundfest, Warren

    2015-01-01

    Inappropriate bone growth in soft tissue can occur after trauma to a limb and can cause a disruption to the healing process. This is known as Heterotopic Ossification (HO) in which regions in the tissue start to mineralize and form microscopic bone-like structures. These structures continue to calcify and develop into large, non-functional bony masses that cause pain, limit limb movement, and expose the tissue to reoccurring infections; in the case of open wounds this can lead to amputation as a result of a failed wound. Both Magnetic Resonance Imaging (MRI) and X-ray imaging have poor sensitivity and specificity for the detection of HO, thus delaying therapy and leading to poor patient outcomes. We present a low-power, fast (1 frame per second) optical Raman imaging system with a large field of view (1 cm2) that can differentiate bone tissue from soft tissue without spectroscopy, this in contrast to conventional Raman microscopy systems. This capability may allow for the development of instrumentation which permits bedside diagnosis of HO. PMID:26504639

  20. Wide-field Raman imaging for bone detection in tissue.

    PubMed

    Papour, Asael; Kwak, Jin Hee; Taylor, Zach; Wu, Benjamin; Stafsudd, Oscar; Grundfest, Warren

    2015-10-01

    Inappropriate bone growth in soft tissue can occur after trauma to a limb and can cause a disruption to the healing process. This is known as Heterotopic Ossification (HO) in which regions in the tissue start to mineralize and form microscopic bone-like structures. These structures continue to calcify and develop into large, non-functional bony masses that cause pain, limit limb movement, and expose the tissue to reoccurring infections; in the case of open wounds this can lead to amputation as a result of a failed wound. Both Magnetic Resonance Imaging (MRI) and X-ray imaging have poor sensitivity and specificity for the detection of HO, thus delaying therapy and leading to poor patient outcomes. We present a low-power, fast (1 frame per second) optical Raman imaging system with a large field of view (1 cm(2)) that can differentiate bone tissue from soft tissue without spectroscopy, this in contrast to conventional Raman microscopy systems. This capability may allow for the development of instrumentation which permits bedside diagnosis of HO.

  1. High spatial and temporal resolution wide-field imaging of neuron activity using quantum NV-diamond.

    PubMed

    Hall, L T; Beart, G C G; Thomas, E A; Simpson, D A; McGuinness, L P; Cole, J H; Manton, J H; Scholten, R E; Jelezko, F; Wrachtrup, Jörg; Petrou, S; Hollenberg, L C L

    2012-01-01

    A quantitative understanding of the dynamics of biological neural networks is fundamental to gaining insight into information processing in the brain. While techniques exist to measure spatial or temporal properties of these networks, it remains a significant challenge to resolve the neural dynamics with subcellular spatial resolution. In this work we consider a fundamentally new form of wide-field imaging for neuronal networks based on the nanoscale magnetic field sensing properties of optically active spins in a diamond substrate. We analyse the sensitivity of the system to the magnetic field generated by an axon transmembrane potential and confirm these predictions experimentally using electronically-generated neuron signals. By numerical simulation of the time dependent transmembrane potential of a morphologically reconstructed hippocampal CA1 pyramidal neuron, we show that the imaging system is capable of imaging planar neuron activity non-invasively at millisecond temporal resolution and micron spatial resolution over wide-fields.

  2. Cosmology with wide-field SZ cluster surveys: selection and systematic effects

    NASA Astrophysics Data System (ADS)

    Juin, J. B.; Yvon, D.; Réfrégier, A.; Yèche, C.

    2007-04-01

    The cosmological potential of large-scale structure observations for cosmology have been extensively discussed in the litterature. In particular, it has recently been shown how Sunyaev-Zel'dovich (SZ) cluster surveys can be used to constrain dark energy parameters. In this paper, we study whether selection and systematics effects will limit future wide-field SZ surveys from achieving their cosmological potential. For this purpose, we use a sky simulation and an SZ-cluster detection software presented in Pires et al. (2006, A&A, 455, 741), using the future Olimpo survey as a concrete example. We show that the SZ-cluster selection function and contamination of SZ-cluster catalogues are more complex than is usually assumed. In particular, the simulated field-to-field detected cluster counts variance can be a factor 3 larger than the expected Poisson fluctuations. We also study the impact of missing redshift information and of the uncertainty of the scaling relations for low mass clusters. We quantify, through hypothesis tests, how near-future SZ experiments can be used to discriminate between different structure formation models. Using a maximum likelihood approach, we then study the impact of these systematics on the joint measurement of cosmological models and of cluster scaling relations.

  3. WiFeS: the wide field spectrograph

    NASA Astrophysics Data System (ADS)

    Dopita, Michael A.; Waldron, Liam E.; McGregor, Peter; Conroy, Peter; Doolan, Matthew C.; Zhelem, Ross; Bloxham, Gabe; Saunders, Will; Jones, Damien; Pfitzner, Lee

    2004-09-01

    WiFeS is a powerful integral field, double-beam, concentric, image-slicing spectrograph designed to deliver excellent thoughput, precision spectrophotometric performance and superb image quality along with wide spectral coverage throughout the 320-1000 nm wavelength region. It is currently under construction at the Research School of Astronomy and Astrophysics of the Australian National University (ANU), and will be mounted on the ANU 2.3m telescope at Siding Spring Observatory. It will provide a 25x31 arc sec field with 0.5 arc sec sampling along each of twenty five 31x1.0 arc sec slitlets. The output format is arranged to match the 4096x4096 pixel CCD detectors in each of two cameras individually optimized for the blue and the red ends of the spectrum, respectively. A process of "interleaved nod-and-shuffle" will be applied to permit quantum noise-limited sky subtraction. Using VPH gratings, spectral resolutions modes of 3000 and 7000 will be provided. The full spectral range is covered in a single exposure in the R=3000 mode, and in two exposures in the R=7000 mode. The use of transmissive coated optics, VPH gratings and optimized mirror coatings ensures a throughput (including telescope and atmosphere) that peaks above 30%. The concentric image-slicer design ensures an excellent and uniform image quality across the full field. To maximize the scientific return, the whole instrument is configured for remote observing, pipeline data reduction, and the accumulation of calibration image libraries.

  4. Broadband and Wide Field-of-view Plasmonic Metasurface-enabled Waveplates

    PubMed Central

    Jiang, Zhi Hao; Lin, Lan; Ma, Ding; Yun, Seokho; Werner, Douglas H.; Liu, Zhiwen; Mayer, Theresa S.

    2014-01-01

    Quasi two-dimensional metasurfaces composed of subwavelength nanoresonator arrays can dramatically alter the properties of light in an ultra-thin planar geometry, enabling new optical functions such as anomalous reflection and refraction, polarization filtering, and wavefront modulation. However, previous metasurface-based nanostructures suffer from low efficiency, narrow bandwidth and/or limited field-of-view due to their operation near the plasmonic resonance. Here we demonstrate plasmonic metasurface-based nanostructures for high-efficiency, angle-insensitive polarization transformation over a broad octave-spanning bandwidth. The structures are realized by optimizing the anisotropic response of an array of strongly coupled nanorod resonators to tailor the interference of light at the subwavelength scale. Nanofabricated reflective half-wave and quarter-wave plates designed using this approach have measured polarization conversion ratios and reflection magnitudes greater than 92% over a broad wavelength range from 640 to 1290 nm and a wide field-of-view up to ±40°. This work outlines a versatile strategy to create metasurface-based photonics with diverse optical functionalities. PMID:25524830

  5. Wide-Field InfraRed Survey Telescope (WFIRST) slitless spectrometer: design, prototype, and results

    NASA Astrophysics Data System (ADS)

    Gong, Qian; Content, David A.; Dominguez, Margaret; Emmett, Thomas; Griesmann, Ulf; Hagopian, John; Kruk, Jeffrey; Marx, Catherine; Pasquale, Bert; Wallace, Thomas; Whipple, Arthur

    2016-07-01

    The slitless spectrometer plays an important role in the WFIRST mission for the survey of emission-line galaxies. This will be an unprecedented very wide field, HST quality 3D survey of emission line galaxies1. The concept of the compound grism as a slitless spectrometer has been presented previously. The presentation briefly discusses the challenges and solutions of the optical design, and recent specification updates, as well as a brief comparison between the prototype and the latest design. However, the emphasis of this paper is the progress of the grism prototype: the fabrication and test of the complicated diffractive optical elements and powered prism, as well as grism assembly alignment and testing. Especially how to use different tools and methods, such as IR phase shift and wavelength shift interferometry, to complete the element and assembly tests. The paper also presents very encouraging results from recent element tests to assembly tests. Finally we briefly touch the path forward plan to test the spectral characteristic, such as spectral resolution and response.

  6. A wide field-of-view microscope based on holographic focus grid

    NASA Astrophysics Data System (ADS)

    Wu, Jigang; Cui, Xiquan; Zheng, Guoan; Lee, Lap Man; Yang, Changhuei

    2010-02-01

    We have developed a novel microscope technique that can achieve wide field-of-view (FOV) imaging and yet possess resolution that is comparable to conventional microscope. The principle of wide FOV microscope system breaks the link between resolution and FOV magnitude of traditional microscopes. Furthermore, by eliminating bulky optical elements from its design and utilizing holographic optical elements, the wide FOV microscope system is more cost-effective. In our system, a hologram was made to focus incoming collimated beam into a focus grid. The sample is put in the focal plane and the transmissions of the focuses are detected by an imaging sensor. By scanning the incident angle of the incoming beam, the focus grid will scan across the sample and the time-varying transmission can be detected. We can then reconstruct the transmission image of the sample. The resolution of microscopic image is limited by the size of the focus formed by the hologram. The scanning area of each focus spot is determined by the separation of the focus spots and can be made small for fast imaging speed. We have fabricated a prototype system with a 2.4-mm FOV and 1-μm resolution. The prototype system was used to image onion skin cells for a demonstration. The preliminary experiments prove the feasibility of the wide FOV microscope technique, and the possibility of a wider FOV system with better resolution.

  7. A 64 Mpixel camera for the Wendelstein Fraunhofer Telescope Nasmyth wide-field port: WWFI

    NASA Astrophysics Data System (ADS)

    Gössl, Claus; Bender, Ralf; Grupp, Frank; Hopp, Ulrich; Lang-Bardl, Florian; Mitsch, Wolfgang; Altmann, Werner; Ayres, Ann; Clark, Scott; Hartl, Michael; Kampf, Dirk; Sims, Gary; Thiele, Hans; Toerne, Kevin

    2010-07-01

    Ludwig-Maximilians-Universität München operates an astrophysical observatory on the summit of Mt. Wendelstein1 which will be equipped with a modern 2m-class, robotic telescope.2 One Nasmyth port of the new Fraunhofer telescope is designed to sustain the excellent (< 0.8" median) seeing of the site [1, Fig. 1] over a FOV of 0.2 deg2 utilizing three-element transmissive field corrector optics for optical wavebands. It will be equipped with a camera built around a customized 64 MPixel Mosaic (Spectral Instruments, 4 × (4k)2 15μm e2v CCDs). TheWendelsteinWide Field Imager has two filter wheels with eight slots each (SDSS3 [ugriz] + eight still free) as well as two off-axis guiding units (two FLI Microline with 2k Fairchild CCDs on differential focus stages). A Bonn Shutter4 ensures high precision photometric exposures. An option to either insert a low dispersion grating (for field spectroscopy) or support a wave front sensor probe allows for further expansion of the camera. EMI-safe housing has to overcome the emission of a close by 0.5MW radio station. Special care has been taken to design a very low ghost budget of the overall system to allow for low-surface brightness applications (e.g. weak lensing surveys).

  8. Wide-Field Emission-Line Imaging of Galactic Supernova Remnants

    NASA Astrophysics Data System (ADS)

    Winkler, P. Frank; Smith, R. Chris

    2001-02-01

    We propose to complete narrow-band emission-line imaging of all the southern supernova remnants (SNRs) for which optical emission has been reported. The great majority of these have never been systematically studied using CCDs. Images in Hα, S II, and O III will enable us to distinguish shock-heated SNR filaments from photo-ionized nebulosity and to search for rare, ejecta-dominated filaments. With matched continuum images we will subtract the stars to give pure emission-line images and reveal faint diffuse features. The results will be used in conjunction with X-ray and radio images for multi-wavelength studies of SNRs and the ISM. We plan to assemble an emission-line atlas of SNRs, to be available in both published form and on-line as digital images. This study requires the unique wide field and fast beam of the Schmidt, so we request sufficient time to complete it in the last semester of this instrument's availability. In addition, we plan deep, broad-band imaging of the SN 1006 remnant in attempt at the first measurement of optical synchrotron emission behind an SNR shock. Detection at the level expected from extrapolation of radio and X-ray power-law spectra would support the picture that Fermi acceleration of electrons to TeV energies produces both X-ray emission and cosmic rays, while significant upper limits would raise questions about this picture.

  9. Fibre assignment in next-generation wide-field spectrographs

    NASA Astrophysics Data System (ADS)

    Morales, Isaac; Montero-Dorta, Antonio D.; Azzaro, Marco; Prada, Francisco; Sánchez, Justo; Becerril, Santiago

    2012-01-01

    We present an optimized algorithm for assigning fibres to targets in next-generation fibre-fed multi-object spectrographs. The method, which we have called the draining algorithm, ensures that the maximum number of targets in a given target field is observed in the first few tiles. Using randomly distributed targets and mock galaxy catalogues, we have estimated that the gain provided by the draining algorithm, compared to a random assignment, can be as much as 2 per cent for the first tiles. For a survey such as the Baryon Oscillation Spectroscopic Survey (BigBOSS), this would imply saving for observation several hundred thousand objects or, alternatively, reducing the covered area in ˜350 deg2. An important advantage of this method is that the fibre collision problem can be solved easily and in an optimal way. We also discuss the additional optimizations of the fibre-positioning process. In particular, we show that if we allow for the rotation of the focal plane, we can improve the efficiency of the process by ˜3.5-4.5 per cent, even if only small adjustments are permitted (up to 2°). For instruments that allow large rotations of the focal plane, the expected gain increases to ˜5-6 per cent. Therefore, these results strongly support the use of focal plane rotation in future spectrographs, as far as the efficiency of the fibre-positioning process is concerned. Finally, we discuss the implications of our optimizations and provide some basic hints for an optimal survey strategy, based on the number of targets per positioner.

  10. A testbed for wide-field, high-resolution, gigapixel-class cameras

    NASA Astrophysics Data System (ADS)

    Kittle, David S.; Marks, Daniel L.; Son, Hui S.; Kim, Jungsang; Brady, David J.

    2013-05-01

    The high resolution and wide field of view (FOV) of the AWARE (Advanced Wide FOV Architectures for Image Reconstruction and Exploitation) gigapixel class cameras present new challenges in calibration, mechanical testing, and optical performance evaluation. The AWARE system integrates an array of micro-cameras in a multiscale design to achieve gigapixel sampling at video rates. Alignment and optical testing of the micro-cameras is vital in compositing engines, which require pixel-level accurate mappings over the entire array of cameras. A testbed has been developed to automatically calibrate and measure the optical performance of the entire camera array. This testbed utilizes translation and rotation stages to project a ray into any micro-camera of the AWARE system. A spatial light modulator is projected through a telescope to form an arbitrary object space pattern at infinity. This collimated source is then reflected by an elevation stage mirror for pointing through the aperture of the objective into the micro-optics and eventually the detector of the micro-camera. Different targets can be projected with the spatial light modulator for measuring the modulation transfer function (MTF) of the system, fiducials in the overlap regions for registration and compositing, distortion mapping, illumination profiles, thermal stability, and focus calibration. The mathematics of the testbed mechanics are derived for finding the positions of the stages to achieve a particular incident angle into the camera, along with calibration steps for alignment of the camera and testbed coordinate axes. Measurement results for the AWARE-2 gigapixel camera are presented for MTF, focus calibration, illumination profile, fiducial mapping across the micro-camera for registration and distortion correction, thermal stability, and alignment of the camera on the testbed.

  11. A testbed for wide-field, high-resolution, gigapixel-class cameras.

    PubMed

    Kittle, David S; Marks, Daniel L; Son, Hui S; Kim, Jungsang; Brady, David J

    2013-05-01

    The high resolution and wide field of view (FOV) of the AWARE (Advanced Wide FOV Architectures for Image Reconstruction and Exploitation) gigapixel class cameras present new challenges in calibration, mechanical testing, and optical performance evaluation. The AWARE system integrates an array of micro-cameras in a multiscale design to achieve gigapixel sampling at video rates. Alignment and optical testing of the micro-cameras is vital in compositing engines, which require pixel-level accurate mappings over the entire array of cameras. A testbed has been developed to automatically calibrate and measure the optical performance of the entire camera array. This testbed utilizes translation and rotation stages to project a ray into any micro-camera of the AWARE system. A spatial light modulator is projected through a telescope to form an arbitrary object space pattern at infinity. This collimated source is then reflected by an elevation stage mirror for pointing through the aperture of the objective into the micro-optics and eventually the detector of the micro-camera. Different targets can be projected with the spatial light modulator for measuring the modulation transfer function (MTF) of the system, fiducials in the overlap regions for registration and compositing, distortion mapping, illumination profiles, thermal stability, and focus calibration. The mathematics of the testbed mechanics are derived for finding the positions of the stages to achieve a particular incident angle into the camera, along with calibration steps for alignment of the camera and testbed coordinate axes. Measurement results for the AWARE-2 gigapixel camera are presented for MTF, focus calibration, illumination profile, fiducial mapping across the micro-camera for registration and distortion correction, thermal stability, and alignment of the camera on the testbed.

  12. A Near IR Fabry-Perot Interferometer for Wide Field, Low Resolution Hyperspectral Imaging on the Next Generation Space Telescope

    NASA Technical Reports Server (NTRS)

    Barry, R. K.; Satyapal, S.; Greenhouse, M. A.; Barclay, R.; Amato, D.; Arritt, B.; Brown, G.; Harvey, V.; Holt, C.; Kuhn, J.

    2000-01-01

    We discuss work in progress on a near-infrared tunable bandpass filter for the Goddard baseline wide field camera concept of the Next Generation Space Telescope (NGST) Integrated Science Instrument Module (ISIM). This filter, the Demonstration Unit for Low Order Cryogenic Etalon (DULCE), is designed to demonstrate a high efficiency scanning Fabry-Perot etalon operating in interference orders 1 - 4 at 30K with a high stability DSP based servo control system. DULCE is currently the only available tunable filter for lower order cryogenic operation in the near infrared. In this application, scanning etalons will illuminate the focal plane arrays with a single order of interference to enable wide field lower resolution hyperspectral imaging over a wide range of redshifts. We discuss why tunable filters are an important instrument component in future space-based observatories.

  13. Status of the GRAAL system development: very wide-field correction with 4 laser guide-stars

    NASA Astrophysics Data System (ADS)

    Paufique, J.; Argomedo, J.; Arsenault, R.; Conzelmann, R.; Donaldson, R.; Hubin, N.; Jochum, L.; Jost, A.; Kiekebusch, M.; Kolb, J.; Kuntschner, H.; Le Louarn, M.; Madec, P.-Y.; Siebenmorgen, R.; Tordo, S.

    2012-07-01

    We recall the design and present the development status of GRAAL, the Ground-layer adaptive optics assisted by Laser, which will deliver wide-field (10 arcmin), enhanced images to the HAWK-I instrument on the VLT, with an improved seeing. GRAAL is an adaptive optics module, part of the Adaptive optics facility (AOF), using four Laser- and one natural guide-stars to measure the turbulence, and correcting for it by deforming the adaptive secondary mirror of a Unit telescope in the Paranal observatory. GRAAL is in the laboratory in Europe and the integration of its laser guide-star optics is completed. The first wave-front sensor camera will be ready for its integration in the coming weeks, allowing the first system tests to start.

  14. OP09O-OP404-9 Wide Field Camera 3 CCD Quantum Efficiency Hysteresis

    NASA Technical Reports Server (NTRS)

    Collins, Nick

    2009-01-01

    The HST/Wide Field Camera (WFC) 3 UV/visible channel CCD detectors have exhibited an unanticipated quantum efficiency hysteresis (QEH) behavior. At the nominal operating temperature of -83C, the QEH feature contrast was typically 0.1-0.2% or less. The behavior was replicated using flight spare detectors. A visible light flat-field (540nm) with a several times full-well signal level can pin the detectors at both optical (600nm) and near-UV (230nm) wavelengths, suppressing the QEH behavior. We are characterizing the timescale for the detectors to become unpinned and developing a protocol for flashing the WFC3 CCDs with the instrument's internal calibration system in flight. The HST/Wide Field Camera 3 UV/visible channel CCD detectors have exhibited an unanticipated quantum efficiency hysteresis (QEH) behavior. The first observed manifestation of QEH was the presence in a small percentage of flat-field images of a bowtie-shaped contrast that spanned the width of each chip. At the nominal operating temperature of -83C, the contrast observed for this feature was typically 0.1-0.2% or less, though at warmer temperatures contrasts up to 5% (at -50C) have been observed. The bowtie morphology was replicated using flight spare detectors in tests at the GSFC Detector Characterization Laboratory by power cycling the detector while cold. Continued investigation revealed that a clearly-related global QE suppression at the approximately 5% level can be produced by cooling the detector in the dark; subsequent flat-field exposures at a constant illumination show asymptotically increasing response. This QE "pinning" can be achieved with a single high signal flat-field or a series of lower signal flats; a visible light (500-580nm) flat-field with a signal level of several hundred thousand electrons per pixel is sufficient for QE pinning at both optical (600nm) and near-UV (230nm) wavelengths. We are characterizing the timescale for the detectors to become unpinned and developing a

  15. Mimir: A Near-Infrared Wide-Field Imager, Spectrometer and Polarimeter

    NASA Astrophysics Data System (ADS)

    Clemens, D. P.; Sarcia, D.; Grabau, A.; Tollestrup, E. V.; Buie, M. W.; Dunham, E.; Taylor, B.

    2007-12-01

    Mimir, a new facility-class near-infrared instrument for the 1.8 m Perkins telescope on Anderson Mesa outside Flagstaff, Arizona, was commissioned and has been operating for three years. Mimir is multifunction, performing wide-field (F/5) and narrow-field (F/17) imaging, long-slit spectroscopy, and imaging polarimetry. The F/5 mode images at 0.59" per pixel onto the 1024 × 1024 pixel ALADDIN III InSb array detector, giving a 10' × 10' field of view. In the F/17 mode, the plate scale is 0.18" per pixel. Optically, Mimir is a refractive reimager for the F/17.5 Perkins beam. A six-lens collimator produces an achromatic 25 mm pupil, which is imaged by a five-lens camera (F/5), a four-lens camera (F/17), or a two-lens pupil viewer onto the detector. Three filter wheels precede the pupil, one follows the pupil. The wheels contain a rotating half-wave plate, broadband filters, narrowband filters, grisms, long-pass filters, a wire grid, and thermal IR blockers. The first telescope focus is within Mimir, where a slit and decker unit, consisting of two linear motion cars, selects one of 13 slit scenes. The slit and decker cars, the four filter wheels, the half-wave plate rotation, and the camera selector are all driven by stepper motors within the cold vacuum space. Cooling is provided by a CTI 1050 two-stage, closed-cycle helium refrigerator, keeping the optics, filters, and internal surfaces between 65 and 75 K and the detector at 33.5 K. Switching between Mimir's different modes takes only a few seconds, making it a versatile tool for conducting a wide range of investigations and for quickly reacting to changing observing conditions. Mimir on the Perkins telescope achieves imaging sensitivities 2-4 mag deeper than 2MASS, moderate resolution (R ˜ 700) JHK spectra of virtually any 2MASS source, high-precision wide-field imaging polarimetry, and L' and M' band imaging and spectroscopy.

  16. Optical Tecnology Developments in Biomedicine: History, Current and Future

    PubMed Central

    Nioka, Shoko; Chen, Yu

    2011-01-01

    Biomedical optics is a rapidly emerging field for medical imaging and diagnostics. This paper reviews several biomedical optical technologies that have been developed and translated for either clinical or pre-clinical applications. Specifically, we focus on the following technologies: 1) near-infrared spectroscopy and tomography, 2) optical coherence tomography, 3) fluorescence spectroscopy and imaging, and 4) optical molecular imaging. There representative biomedical applications are also discussed here. PMID:23905030

  17. Design of wide-field submillimeter-wave camera using SIS photon detectors

    NASA Astrophysics Data System (ADS)

    Matsuo, Hiroshi; Ariyoshi, Seiichiro; Otani, Chiko; Ezawa, Hajime; Kobayashi, Jun; Mori, Yuko; Nagata, Hirohisa; Shimizu, Hirohiko M.; Fujiwara, Mikio; Akiba, Makoto; Hosako, Iwao

    2004-10-01

    SIS photon detectors are niobium-based superconducting direct detectors for submillimeter-wave that show superior performance when compared with bolometric detectors for ground-based observations. We present the design and development of the SIS photon detectors together with optical and cryogenic components for wide field continuum observation system on Atacama Submillimeter Telescope Experiment (ASTE). Using antenna coupled distributed junctions, SIS photon detectors give wide band response in a 650-GHz atmospheric window as well as high current sensitivity, shot noise limited operation, fast response and high dynamic range. Optical noise equivalent power (NEP) was measured to be 1.6x10-16 W/Hz0.5 that is less than the background photon fluctuation limit for ground based submillimeter-wave observations. Fabrication of focal plane array with 9 detector pixels is underway to install in ASTE. Readout electronics with Si-JFETs operating at about 100 K will be used for this array. Development of readout electronics for larger array is based on GaAs-JFETs operating at 0.3 K. For the purpose of installing 100 element array of SIS photon detectors, we have developed remotely operable low-vibration cryostat, which now cools bolometers for 350, 450, 850-µm observations down to 0.34 K. GM-type 4-K cooler and He3/He4 sorption cooler is used, which can be remotely recycled to keep detectors at 0.34 K. Since we have large optical window for this cryostat, sapphire cryogenic window is used to block infrared radiation. The sapphire window is ante-reflection coated with SiO2 by chemical vapor deposition (CVD). The transmittance of the cryogenic window at 650 GHz is more than 95%.

  18. The Power of Wide Field HI Surveys: ALFALFA Imaging of Massive Tidal Features in the Leo Cloud of Galaxies

    NASA Astrophysics Data System (ADS)

    Leisman, Luke; Haynes, Martha P.; Giovanelli, Riccardo; ALFALFA Almost Darks Team

    2016-01-01

    Tidal interactions are well known to play an important role in galactic evolution in group environments, but the extent of these interactions, and their relative impact on the morphology-density relation is still unclear. Neutral hydrogen (HI) mapping can reveal the recent interaction history of group galaxies, but is difficult to execute due to the need for high sensitivity over wide fields. The Arecibo Legacy Fast ALFA survey (ALFALFA; Giovanelli et al. 2005; Haynes et al. 2011) provides high sensitivity, unbiased, wide field maps of HI in the local volume; here we will present a 50 deg2 ALFALFA map of a well studied region of the Leo Cloud of galaxies, which includes the NGC3226/7 group and HCG44. These observations reveal HI tails and plumes with extents exceeding 1.4 deg (~600 kpc), well beyond the primary beams of previous observations. These tails constitute a significant fraction of the total HI mass in NGC3226/7 (Arp 94) and HCG44. We will also present WSRT maps of the extended emission near Arp 94, which show tail morphologies inconsistent with 2 body interactions. These observations demonstrate that large scale group interactions will be an important science outcome for future sensitive, wide field HI surveys.This work is supported by NSF grants AST-0607007 and AST-1107390 and by grants from the Brinson Foundation.

  19. Managing the Development of the Wide-Field Infrared Survey Explorer Mission

    NASA Technical Reports Server (NTRS)

    Irace, William; Cutri, Roc; Duval, Valerie; Eisenhardt, Peter; Elwell, John; Greanias, George; Heinrichsen, Ingolf; Howard, Joan; Liu, Feng-Chuan; Royer, Donald; Wright, Edward L.

    2010-01-01

    The Wide-field Infrared Survey Explorer (WISE), a NASA Medium-Class Explorer (MIDEX) mission, is surveying the entire sky in four bands from 3.4 to 22 microns with a sensitivity hundreds to hundreds of thousands times better than previous all-sky surveys at these wavelengths. The single WISE instrument consists of a 40 cm three-mirror anastigmatic telescope, a two-stage solid hydrogen cryostat, a scan mirror mechanism, and reimaging optics giving 6" resolution (full-width-half-maximum). WISE was placed into a Sun-synchronous polar orbit on a Delta II 7320 launch vehicle on December 14, 2009. NASA selected WISE as a MIDEX in 2002 following a rigorous competitive selection process. To gain further confidence in WISE, NASA extended the development period one year with an option to cancel the mission if certain criteria were not met. MIDEX missions are led by the principal investigator who in this case delegated day-to-day management to the project manager. With a cost cap and relatively short development schedule, it was essential for all WISE partners to work seamlessly together. This was accomplished with an integrated management team representing all key partners and disciplines. The project was developed on budget and on schedule in spite of the need to surmount significant technical challenges. This paper describes our management approach, key challenges and critical decisions made. Results are described from a programmatic, technical and scientific point of view. Lessons learned are offered for projects of this type.

  20. New wide field camera for Subaru Telescope: Hyper Suprime-Cam

    NASA Astrophysics Data System (ADS)

    Miyazaki, Satoshi

    2015-08-01

    Hyper Suprime-Cam (HSC) is a new wide field optical imaging camera built for 8.2 m Subaru telescope. The field of view is 1.5 degree in diameter and the nearly 50 cm image circle was paved by 116 fully depleted CCDs (2k x 4k 15 micron square pixels). To realize a seeing limit imaging at Mauna Kea, the specification on the overall instrument PSF is set as 0.32 arc-second (FWHM). This is crucial for our primary scientific objectives: weak gravitational lensing survey to probe dark matter distribution. We started building the camera in 2006 and had a first light in 2012. The delivered image quality turned out to be mostly seeing limited as designed. We once observed the seeing size of 0.43 arc-second (median value over the field of view) in Y-band with 300 seconds exposure. Our 300 nights observing proposal has been accepted. The program started in March 2014 and continues over 5 years. The wide survey plans to cover 1,400 square degree with the limiting magnitude of i_AB = 26 (5 sigma, 2 arcsec aperture). General observer programs are carried out in parallel. In this talk, we will present the design and the actual performance of the camera as well as how we implement the massive (1.6 GByte/exposure) data management system.

  1. Automated segmentation of oral mucosa from wide-field OCT images (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Goldan, Ryan N.; Lee, Anthony M. D.; Cahill, Lucas; Liu, Kelly; MacAulay, Calum; Poh, Catherine F.; Lane, Pierre

    2016-03-01

    Optical Coherence Tomography (OCT) can discriminate morphological tissue features important for oral cancer detection such as the presence or absence of basement membrane and epithelial thickness. We previously reported an OCT system employing a rotary-pullback catheter capable of in vivo, rapid, wide-field (up to 90 x 2.5mm2) imaging in the oral cavity. Due to the size and complexity of these OCT data sets, rapid automated image processing software that immediately displays important tissue features is required to facilitate prompt bed-side clinical decisions. We present an automated segmentation algorithm capable of detecting the epithelial surface and basement membrane in 3D OCT images of the oral cavity. The algorithm was trained using volumetric OCT data acquired in vivo from a variety of tissue types and histology-confirmed pathologies spanning normal through cancer (8 sites, 21 patients). The algorithm was validated using a second dataset of similar size and tissue diversity. We demonstrate application of the algorithm to an entire OCT volume to map epithelial thickness, and detection of the basement membrane, over the tissue surface. These maps may be clinically useful for delineating pre-surgical tumor margins, or for biopsy site guidance.

  2. Telescope Fabra ROA Montsec: A New Robotic Wide Field Baker–Nunn Facility

    NASA Astrophysics Data System (ADS)

    Fors, Octavi; Núñez, Jorge; Muiños, José Luis; Montojo, Francisco Javier; Baena-Gallé, Roberto; Boloix, Jaime; Morcillo, Ricardo; Merino, María Teresa; Downey, Elwood C.; Mazur, Michael J.

    2013-05-01

    A Baker–Nunn Camera (BNC), originally installed at the Real Instituto y Observatorio de la Armada (ROA) in 1958, was refurbished and robotized. The new facility, called Telescope Fabra ROA Montsec (TFRM), was installed at the Observatori Astronòmic del Montsec (OAdM). The process of refurbishment is described in detail. Most of the steps of the refurbishment project were accomplished by purchasing commercial components, which involve little posterior engineering assembling work. The TFRM is a 0.5 m aperture f/0.96 optically modified BNC, which offers a unique combination of instrumental specifications: fully robotic and remote operation, wide field of view (4°.4 × 4°.4), moderate limiting magnitude (V ∼ 19.5 mag), ability of tracking at arbitrary right ascension (α) and declination (δ) rates, as well as opening and closing CCD shutter at will during an exposure. Nearly all kinds of image survey programs can benefit from those specifications. Apart from other less time-consuming programs, since the beginning of science TFRM operations we have been conducting two specific and distinct surveys: super-Earths transiting around M-type dwarfs stars, and geostationary debris in the context of Space Situational Awareness/Space Surveillance and Tracking (SSA/SST) programs. Preliminary results for both cases will be shown.

  3. WIDE-FIELD MULTIBAND PHOTOMETRY OF GLOBULAR CLUSTER SYSTEMS IN THE FORNAX GALAXY CLUSTER

    SciTech Connect

    Kim, Hak-Sub; Yoon, Suk-Jin; Chung, Chul; Lee, Sang-Yoon; Lee, Young-Wook; Sohn, Sangmo Tony; Kim, Sang Chul; Kim, Eunhyeuk

    2013-01-20

    We present wide-field multiband photometry of globular cluster (GC) systems in NGC 1399, NGC 1404, and NGC 1387 located in the central region of the Fornax galaxy cluster. Observation was carried out through U, B, V, and I bands, which marks one of the widest and deepest U-band studies on extragalactic GC systems. The present U-band photometry enables us to significantly reduce the contamination by a factor of two for faint sources (V {sub 0} {approx} 23.5). The main results based on some 2000 GC candidates around NGC 1399, NGC 1404, and NGC 1387 are as follows: (1) the GC system in each galaxy exhibits bimodal color distributions in all colors examined, but the shape of color histograms varies systematically depending on colors; (2) NGC 1399 shows that the mean colors of both blue and red GCs become bluer with increasing galactocentric radius; (3) NGC 1399 shows overabundance of GCs in the directions of NGC 1404 and NGC 1387, indicating their ongoing interactions; and (4) NGC 1399 also exhibits a {approx}0.'5 offset between the center of the inner GC distribution and the galaxy's optical center, suggesting that NGC 1399 is not yet dynamically relaxed and may be undergoing merger events.

  4. Development of a prototype of the Tomo-e Gozen wide-field CMOS camera

    NASA Astrophysics Data System (ADS)

    Sako, Shigeyuki; Osawa, Ryou; Takahashi, Hidenori; Kikuchi, Yuki; Doi, Mamoru; Kobayashi, Naoto; Aoki, Tsutomu; Arimatsu, Ko; Ichiki, Makoto; Ikeda, Shiro; Ita, Yoshifusa; Kasuga, Toshihiro; Kawakita, Hideyo; Kokubo, Mitsuru; Maehara, Hiroyuki; Matsunaga, Noriyuki; Mito, Hiroyuki; Mitsuda, Kazuma; Miyata, Takashi; Mori, Kiyoshi; Mori, Yuki; Morii, Mikio; Morokuma, Tomoki; Motohara, Kentaro; Nakada, Yoshikazu; Osawa, Kentaro; Okumura, Shin-ichiro; Onozato, Hiroki; Sarugaku, Yuki; Sato, Mikiya; Shigeyama, Toshikazu; Soyano, Takao; Tanaka, Masaomi; Taniguchi, Yuki; Tanikawa, Ataru; Tarusawa, Ken'ichi; Tominaga, Nozomu; Totani, Tomonori; Urakawa, Seitaro; Usui, Fumihiko; Watanabe, Junichi; Yamaguchi, Jumpei; Yoshikawa, Makoto

    2016-08-01

    The Tomo-e Gozen is an extremely wide-field optical camera for the Kiso 1.0-m Schmidt telescope. It is capable of taking consecutive frames with a field-of-view of 20 deg2 and a sub-second time-resolution, which are achieved by 84 chips of 2k×1k CMOS sensor. This camera adopts unconventional designs including a lightweight structure, a nonvacuumed and naturally-air cooled system, front-side-illuminated CMOS sensors with microlens arrays, a sensor alignment along a spherical focal plane of the telescope, and massive readout electronics. To develop technical components necessary for the Tomo-e Gozen and confirm a feasibility of its basic design, we have developed a prototype-model (PM) of the Tomo-e Gozen prior to the final-model (FM). The Tomo-e PM is equipped with eight chips of the CMOS sensor arranged in a line along the RA direction, covering a sky area of 2.0 deg2. The maximum frame rate is 2 fps. The total data production rate is 80 MByte sec-1 at 2 fps, corresponding to approximately 3 TByte night-1. After laboratory testing, we have successfully obtained consecutive movie data at 2 fps with the Tomo-e PM in the first commissioning run conducted in the end of 2015.

  5. Spectro-spatial reconstruction of Wide Field Imaging Interferometry Testbed (WIIT) data

    NASA Astrophysics Data System (ADS)

    Juanola-Parramon, Roser; Leisawitz, David; Bolcar, Matthew R.; Iacchetta, Alexander; Maher, Stephen F.; Rinehart, Stephen

    2017-01-01

    The Wide-field Imaging Interferometry Testbed (WIIT) is a double Fourier interferometer (DF) operating at optical wavelengths, and provides data that are highly representative of those from a space-based far-infrared interferometer like SPIRIT. Developed at NASA’s Goddard Space Flight Center, this testbed produces high-quality interferometric data and is capable of observing spatially and spectrally complex hyperspectral test scenes, from geometrically simple to astronomically representative test scenes. Here we present the reconstruction of WIIT data via spectro-spatial Fourier transformation, where the spectral domain and the spatial domain are synthesized independently, offering the opportunity to apply algorithms classically used in spectroscopy and radio interferometry. For this current study, the test scene under consideration spatially consists of four reference point sources intended for spectral and spatial calibration, and six science sources, comprised of binary systems. Each binary pair member has a unique spectrum. Our results demonstrate the synthesis of real double Fourier interferometry data, and we compare them with synthesized datacubes reconstructed from simulated data generated by the Far-infrared Interferometer Instrument Simulator (FIInS).

  6. Intact skull chronic windows for mesoscopic wide-field imaging in awake mice

    PubMed Central

    Silasi, Gergely; Xiao, Dongsheng; Vanni, Matthieu P.; Chen, Andrew C. N.; Murphy, Timothy H.

    2016-01-01

    Background Craniotomy-based window implants are commonly used for microscopic imaging, in head-fixed rodents, however their field of view is typically small and incompatible with mesoscopic functional mapping of cortex. New Method We describe a reproducible and simple procedure for chronic through-bone wide-field imaging in awake head-fixed mice providing stable optical access for chronic imaging over large areas of the cortex for months. Results The preparation is produced by applying clear-drying dental cement to the intact mouse skull, followed by a glass coverslip to create a partially transparent imaging surface. Surgery time takes about 30 minutes. A single set-screw provides a stable means of attachment for mesoscale assessment without obscuring the cortical field of view. Comparison with Existing Methods We demonstrate the utility of this method by showing seed-pixel functional connectivity maps generated from spontaneous cortical activity of GCAMP6 signals in both awake and anesthetized mice. Conclusions We propose that the intact skull preparation described here may be used for most longitudinal studies that do not require micron scale resolution and where cortical neural or vascular signals are recorded with intrinsic sensors. PMID:27102043

  7. Wide-field Infrared Survey Explorer cryogenic support system lessons learned

    NASA Astrophysics Data System (ADS)

    Lloyd, Brett; Thompson, Brian; Schick, Scott

    2010-08-01

    The Wide-Field Infrared Survey Explorer (WISE) is a JPL-managed MIDEX mission to perform an infrared all-sky survey. The WISE instrument, developed by the Space Dynamics Laboratory (SDL), is a 40-cm cryogenically-cooled telescope which includes a cryogenic scan mirror and four infrared focal planes (2-HgCdTe, 2-Si:As). Cooling the instrument to the desired temperatures is accomplished by a two-stage, solid hydrogen cryostat, provided by Lockheed Martin Advanced Technology Center (LMATC). Required temperatures for the instrument optics and Si:As focal planes are <13 K and <7.6 K respectively. To reduce heat loads, the vacuum shell is isolated from the spacecraft bus via composite struts and radiatively cooled to <200 K. The telescope aperture is protected from on-orbit environmental loads via a two-stage radiatively cooled aperture shade. WISE was successfully launched into a 530 km, polar orbit on December 14, 2009, beginning a 10-month mission to survey the entire sky in the infrared.

  8. Polarization mosaicing: high dynamic range and polarization imaging in a wide field of view

    NASA Astrophysics Data System (ADS)

    Schechner, Yoav Y.; Nayar, Shree K.

    2003-12-01

    We present an approach for imaging the polarization state of scene points in a wide field of view, while enhancing the radiometric dynamic range of imaging systems. This is achieved by a simple modification of image mosaicking, which is a common technique in remote sensing. In traditional image mosaics, images taken in varying directions or positions are stitched to obtain a larger image. Yet, as the camera moves, it senses each scene point multiple times in overlapping regions of the raw frames. We rigidly attach to the camera a fixed, spatially varying polarization and attenuation filter. This way, the camera motion-induced multiple measurements per scene point are taken under different optical settings. This is in contrast to the redundant measurements of traditional mosaics. Computational algorithms then analyze the data to extract polarization imaging with high dynamic range across the mosaic field of view. We developed a Maximum Likelihood method to automatically register the images, in spite of the challenging spatially varying effects. Then, we use Maximum Likelihood to handle, in a single framework, variable exposures (due to transmittance variations), saturation, and partial polarization filtering. As a by product, these results enable polarization settings of cameras to change while the camera moves, alleviating the need for camera stability. This work demonstrates the modularity of the Generalized Mosaicing approach, which we recently introduced for multispectral image mosaics. The results are useful for the wealth of polarization imaging applications, in addition to mosaicking applications, particularly remote sensing. We demonstrate experimental results obtained using a system we built.

  9. Characterization of high proper motion objects from the wide-field infrared survey explorer

    SciTech Connect

    Luhman, K. L.; Sheppard, Scott S.

    2014-06-01

    We present an analysis of high proper motion objects that we have found in a recent study and in this work with multi-epoch astrometry from the Wide-field Infrared Survey Explorer (WISE). Using photometry and proper motions from the Two Micron All-Sky Survey and WISE, we have identified the members of this sample that are likely to be late-type, nearby, or metal-poor. We have performed optical and near-infrared spectroscopy on 41 objects, from which we measure spectral types that range from M4-T2.5. This sample includes 11 blue L dwarfs and 5 subdwarfs; the latter were also classified as such in the recent study by Kirkpatrick and coworkers. Based on their spectral types and photometry, several of our spectroscopic targets may have distances of <20 pc with the closest at ∼12 pc. The tangential velocities implied by the spectrophotometric distances and proper motions indicate that four of the five subdwarfs are probably members of the Galactic halo while several other objects, including the early-T dwarf WISE J210529.08–623558.7, may belong to the thick disk.

  10. Miniature wide field-of-view star trackers for spacecraft attitude sensing and navigation

    NASA Technical Reports Server (NTRS)

    Mccarty, William; Curtis, Eric; Hull, Anthony; Morgan, William

    1993-01-01

    Introducing a family of miniature, wide field-of-view star trackers for low cost, high performance spacecraft attitude determination and navigation applications. These devices, derivative of the WFOV Star Tracker Camera developed cooperatively by OCA Applied Optics and the Lawrence Livermore National Laboratory for the Brilliant Pebbles program, offer a suite of options addressing a wide range of spacecraft attitude measurement and control requirements. These sensors employ much wider fields than are customary (ranging between 20 and 60 degrees) to assure enough bright stars for quick and accurate attitude determinations without long integration intervals. The key benefit of this approach are light weight, low power, reduced data processing loads and high information carrier rates for wide ACS bandwidths. Devices described range from the proven OCA/LLNL WFOV Star Tracker Camera (a low-cost, space-qualified star-field imager utilizing the spacecraft's own computer and centroiding and position-finding), to a new autonomous subsystem design featuring dual-redundant cameras and completely self-contained star-field data processing with output quaternion solutions accurate to 100 micro-rad, 3 sigma, for stand-alone applications.

  11. Design of four-mirror afocal principal system for wide field multichannel infrared imaging

    NASA Astrophysics Data System (ADS)

    Hu, Bin; Huang, Ying; Li, Yan

    2015-08-01

    The image space scanning system is widely used for multichannel infrared imaging to overcome the absence of large infrared focal plane array. The field of view of afocal system directly influences the time resolution of the image space scanning system. The field of view of afocal system is generally less than 7°. Therefore, it is significant to design larger field of view of afocal system for increasing time resolution. The method of four-mirror afocal system design based on primary aberration is explored. The structural parameters are calculated according to magnification and obscuration ratio of each mirror. The conic parameters are calculated according to primary aberration coefficients. The procedure for calculating initial structural parameters is programmed. Then a four-mirror afocal system is designed with an entrance pupil diameter of 200mm, a field of view of 20°×1°, the operating wave band of 3~12μm, compression ratio of 2.5 times and the distance of exit pupil of 620mm. The results indicate that the maximum root mean square (RMS) wavefront error is less than 0.042λ(λ=7.5μm), the maximum optical path difference(OPD) is less than λ/4(λ=3~12μm). It has high imaging quality and the modulation transfer function (MTF) is approached to the diffraction limit. The method of afocal system design can be widely used for wide field multichannel infrared imaging.

  12. Wide-field laser ophthalmoscopy for imaging of gas-filled eyes after macular hole surgery

    PubMed Central

    Nakao, Shintaro; Arita, Ryoichi; Sato, Yuki; Enaida, Hiroshi; Ueno, Akifumi; Matsui, Takaaki; Salehi-Had, Hani; Ishibashi, Tatsuro; Sonoda, Koh-hei

    2016-01-01

    Background and objective Existing ophthalmoscopy methods are unable to obtain clear fundus autofluorescence (FAF) images in gas-filled eyes. The purpose of this study was to evaluate the capability of wide-field laser ophthalmoscopy (Optos) in obtaining FAF images in gas-filled eyes for the assessment of macular hole (MH) closure after surgery. Methods This was an interventional case series. Eighteen consecutive patients with unilateral MH underwent vitrectomy with internal limiting membrane peeling and 20% sulfur hexafluoride gas tamponade. FAF images using Optos were recorded preoperatively and postoperatively (days 1, 2, and 7). Results On postoperative days 1, 2, and 7, FAF images were obtained from 11/18 (61.1%), 9/18 (50.0%), and 17/18 eyes (94.4%), respectively, using Optos. The quality of FAF images using Optos was sufficient to determine MH closure in 9/18 (50.0%) of gas-filled eyes postoperatively. Quantitative analysis of FAF images was helpful in determining complete or partial closure of the MH. Conclusion FAF imaging using Optos might be a useful adjunct to optical coherence tomography as a supportive method to guide the release from facedown posturing in some cases of MH. PMID:27601877

  13. High-speed depth-sectioned wide-field imaging using low-coherence photorefractive holographic microscopy

    NASA Astrophysics Data System (ADS)

    Dunsby, C.; Gu, Y.; Ansari, Z.; French, P. M. W.; Peng, L.; Yu, P.; Melloch, M. R.; Nolte, D. D.

    2003-04-01

    Low-coherence photorefractive holography has the potential to acquire wide-field coherence-gated images at frame rates approaching 1000 frames/s, including through scattering media. We present a quantitative analysis of the system optimization and limits of performance for coherence-gated imaging through scattering media using photorefractive holography and compare this performance to direct CCD detection. We show that, for high optical quality recording photorefractive multiple quantum well devices, photorefractive holography has the potential to provide a higher dynamic range than is possible with direct CCD-based detection.

  14. Development and clinical translation of OTIS: a wide-field OCT imaging device for ex-vivo tissue characterization

    NASA Astrophysics Data System (ADS)

    Munro, Elizabeth A.; Rempel, David; Danner, Christine; Atchia, Yaaseen; Valic, Michael S.; Berkeley, Andrew; Davoudi, Bahar; Magnin, Paul A.; Akens, Margarete; Done, Susan J.; Kulkarni, Supriya; Leong, Wey-Liang; Wilson, Brian C.

    2016-03-01

    We have developed an automated, wide-field optical coherence tomography (OCT)-based imaging device (OTISTM Perimeter Medical Imaging) for peri-operative, ex-vivo tissue imaging. This device features automated image acquisition, enabling rapid capture of high-resolution (15 μm) OCT images from samples up to 10 cm in diameter. We report on the iterative progression of device development from phantom and pre-clinical (tumor xenograft) models through to initial clinical results. We discuss the challenges associated with proving a novel imaging technology against the clinical "gold standard" of conventional post-operative pathology.

  15. Optical lead flint glasses: key material in optics since centuries and in future

    NASA Astrophysics Data System (ADS)

    Hartmann, Peter

    2015-09-01

    fluorescence light bands simultaneously. These outstanding properties of the lead flint glass types caused SCHOTT to keep them in the glass program and not to replace them completely as other glass companies have done. The improvements of the last two decades with respect to homogeneity and transmittance underline their suitability for future extreme quality optics with applications in medical and general research and in astronomy for large beam shaping and atmospheric dispersion correction.

  16. Cost-effective and compact wide-field fluorescent imaging on a cell-phone.

    PubMed

    Zhu, Hongying; Yaglidere, Oguzhan; Su, Ting-Wei; Tseng, Derek; Ozcan, Aydogan

    2011-01-21

    We demonstrate wide-field fluorescent and darkfield imaging on a cell-phone with compact, light-weight and cost-effective optical components that are mechanically attached to the existing camera unit of the cell-phone. For this purpose, we used battery powered light-emitting diodes (LEDs) to pump the sample of interest from the side using butt-coupling, where the pump light was guided within the sample cuvette to uniformly excite the specimen. The fluorescent emission from the sample was then imaged using an additional lens that was positioned right in front of the existing lens of the cell-phone camera. Because the excitation occurs through guided waves that propagate perpendicular to our detection path, an inexpensive plastic colour filter was sufficient to create the dark-field background required for fluorescent imaging, without the need for a thin-film interference filter. We validate the performance of this platform by imaging various fluorescent micro-objects in 2 colours (i.e., red and green) over a large field-of-view (FOV) of ∼81 mm(2) with a raw spatial resolution of ∼20 μm. With additional digital processing of the captured cell-phone images, through the use of compressive sampling theory, we demonstrate ∼2 fold improvement in our resolving power, achieving ∼10 μm resolution without a trade-off in our FOV. Further, we also demonstrate darkfield imaging of non-fluorescent specimen using the same interface, where this time the scattered light from the objects is detected without the use of any filters. The capability of imaging a wide FOV would be exceedingly important to probe large sample volumes (e.g., >0.1 mL) of e.g., blood, urine, sputum or water, and for this end we also demonstrate fluorescent imaging of labeled white-blood cells from whole blood samples, as well as water-borne pathogenic protozoan parasites such as Giardia Lamblia cysts. Weighing only ∼28 g (∼1 ounce), this compact and cost-effective fluorescent imaging platform

  17. SAAO's new robotic telescope and WiNCam (Wide-field Nasmyth Camera)

    NASA Astrophysics Data System (ADS)

    Worters, Hannah L.; O'Connor, James E.; Carter, David B.; Loubser, Egan; Fourie, Pieter A.; Sickafoose, Amanda; Swanevelder, Pieter

    2016-08-01

    The South African Astronomical Observatory (SAAO) is designing and manufacturing a wide-field camera for use on two of its telescopes. The initial concept was of a Prime focus camera for the 74" telescope, an equatorial design made by Grubb Parsons, where it would employ a 61mmx61mm detector to cover a 23 arcmin diameter field of view. However, while in the design phase, SAAO embarked on the process of acquiring a bespoke 1-metre robotic alt-az telescope with a 43 arcmin field of view, which needs a homegrown instrument suite. The Prime focus camera design was thus adapted for use on either telescope, increasing the detector size to 92mmx92mm. Since the camera will be mounted on the Nasmyth port of the new telescope, it was dubbed WiNCam (Wide-field Nasmyth Camera). This paper describes both WiNCam and the new telescope. Producing an instrument that can be swapped between two very different telescopes poses some unique challenges. At the Nasmyth port of the alt-az telescope there is ample circumferential space, while on the 74 inch the available envelope is constrained by the optical footprint of the secondary, if further obscuration is to be avoided. This forces the design into a cylindrical volume of 600mm diameter x 250mm height. The back focal distance is tightly constrained on the new telescope, shoehorning the shutter, filter unit, guider mechanism, a 10mm thick window and a tip/tilt mechanism for the detector into 100mm depth. The iris shutter and filter wheel planned for prime focus could no longer be accommodated. Instead, a compact shutter with a thickness of less than 20mm has been designed in-house, using a sliding curtain mechanism to cover an aperture of 125mmx125mm, while the filter wheel has been replaced with 2 peripheral filter cartridges (6 filters each) and a gripper to move a filter into the beam. We intend using through-vacuum wall PCB technology across the cryostat vacuum interface, instead of traditional hermetic connector-based wiring. This

  18. A Single Wide-Field OCT Protocol Can Provide Compelling Information for the Diagnosis of Early Glaucoma

    PubMed Central

    Hood, Donald C.; De Cuir, Nicole; Blumberg, Dana M.; Liebmann, Jeffrey M.; Jarukasetphon, Ravivarn; Ritch, Robert; De Moraes, Carlos G.

    2016-01-01

    Purpose To evaluate a report for glaucoma diagnosis based on a single optical coherence tomography (OCT) protocol. Methods A wide-field (9 × 12 mm) swept-source (SS) OCT scan, encompassing the macula and disc, was obtained on 130 eyes (patients) with or suspected open-angle glaucoma, a mean deviation greater than or equal to −6 dB on a 24-2 visual field (VF), and spherical refractive error between ± 6 diopters (D). The single-page report contained a circumpapillary retinal nerve fiber layer (cpRNFL) thickness plot; retinal ganglion cell layer and retinal nerve fiber layer (RNFL) thickness and probability plots of the macula and optic nerve; and an enface slab image of the optic nerve. A report specialist judged each eye as healthy (H); probably healthy (PH); forced-choice healthy (FC-H); optic neuropathy (ON); probably ON (PON); forced-choice optic neuropathy (FC-ON). Two glaucoma specialists made similar judgments about the presence of glaucomatous damage. The glaucoma specialists had 24-2 and 10-2 VFs, fundus photos, patient chart information, and the single-page report including the report specialist's interpretation. Results The reference standard consisted of 57 eyes judged as glaucomatous (ON or PON) and 45 eyes judged as healthy (H or PH) by both glaucoma specialists. The report specialist identified 56 of the glaucomatous eyes as optic neuropathy (i.e., ON, PON, or FC-ON), and 44 of the healthy eyes as healthy (i.e., H, PH, or FC-H), an accuracy of 98.0%. Conclusions A single-page report based upon a single, wide-field OCT scan has the information needed to diagnose early glaucoma with excellent sensitivity/specificity. Translational Relevance It is possible that screening for glaucoma can be effective with only a single OCT protocol. PMID:27847691

  19. Demonstration of the Wide-Field Imaging Interferometer Testbed Using a Calibrated Hyperspectral Image Projector

    NASA Technical Reports Server (NTRS)

    Bolcar, Matthew R.; Leisawitz, David; Maher, Steve; Rinehart, Stephen

    2012-01-01

    The Wide-field Imaging Interferometer testbed (WIIT) at NASA's Goddard Space Flight Center uses a dual-Michelson interferometric technique. The WIIT combines stellar interferometry with Fourier-transform interferometry to produce high-resolution spatial-spectral data over a large field-of-view. This combined technique could be employed on future NASA missions such as the Space Infrared Interferometric Telescope (SPIRIT) and the Sub-millimeter Probe of the Evolution of Cosmic Structure (SPECS). While both SPIRIT and SPECS would operate at far-infrared wavelengths, the WIIT demonstrates the dual-interferometry technique at visible wavelengths. The WIIT will produce hyperspectral image data, so a true hyperspectral object is necessary. A calibrated hyperspectral image projector (CHIP) has been constructed to provide such an object. The CHIP uses Digital Light Processing (DLP) technology to produce customized, spectrally-diverse scenes. CHIP scenes will have approximately 1.6-micron spatial resolution and the capability of . producing arbitrary spectra in the band between 380 nm and 1.6 microns, with approximately 5-nm spectral resolution. Each pixel in the scene can take on a unique spectrum. Spectral calibration is achieved with an onboard fiber-coupled spectrometer. In this paper we describe the operation of the CHIP. Results from the WIIT observations of CHIP scenes will also be presented.

  20. A DEEP, WIDE-FIELD H{alpha} SURVEY OF NEARBY CLUSTERS OF GALAXIES: DATA

    SciTech Connect

    Sakai, Shoko; Kennicutt, Robert C. Jr.; Moss, Chris

    2012-04-01

    We present the results of a wide-field H{alpha} imaging survey of eight nearby (z = 0.02-0.03) Abell clusters. We have measured H{alpha} fluxes and equivalent widths for 465 galaxies, of which 360 are new detections. The survey was designed to obtain complete emission-line-selected inventories of star-forming galaxies in the inner regions of these clusters, extending to star formation rates below 0.1 M{sub Sun} yr{sup -1}. This paper describes the observations, data processing, and source identification procedures, and presents an H{alpha} and R-band catalog of detected cluster members and other candidates. Future papers in the series will use these data to study the completeness of spectroscopically based star formation surveys, and to quantify the effects of cluster environment on the present-day populations of star-forming galaxies. The data will also provide a valuable foundation for imaging surveys of redshifted H{alpha} emission in more distant clusters.

  1. From classical to modern near-field optics and the future

    NASA Astrophysics Data System (ADS)

    Ohtsu, Motoichi

    2014-11-01

    This paper reviews the framework of classical near-field optics and recent progress in modern near-field optics. Some applications are also reviewed, including novel optical functional devices, nano-fabrication technologies, energy conversion technologies, and information processing systems. Novel theoretical models based on mathematical science are also presented, as well as an outlook for the future, hinting at the possibilities of near-field optics.

  2. Towards future systems with nano-optics contributions

    NASA Astrophysics Data System (ADS)

    Kaminska, Bozena; Najiminaini, Mohamadreza; Chuo, Yindar; Landrock, Clint; Omrane, Badr; Carson, Jeffrey J. L.

    2013-03-01

    The long anticipated deployment of nano-optics that can enable next generation computing has encountered several practical impediments that have delayed widespread adoption in commercial processes. However, the global market in nano-enabled products is expected to grow to over $80B USD within the next 3 years. In response, the research community is creating solutions to overcome challenging issues such as reliability and cost-effective fabrication. New approaches in sensing, continuous uptime powering, and post silicon manufacturing will maximize overall performance and allow unprecedented commercial applications. This paper reviews present limitations of nano-optics and then considers the new generation of devices and their manufacturing that may turn promises into reality. We highlight several recent innovations: high sensitivity/selectivity nano-optical sensing devices; sustainable power from polymer energy harvesting and storage; optical variable devices for visual authentication of secure documents; and nano-template masters for high-volume manufacturing.

  3. The development of high-precision hexapod actuators for the Hobby-Eberly Telescope wide field upgrade

    NASA Astrophysics Data System (ADS)

    Zierer, Joseph J.; Mock, Jason R.; Beno, Joseph H.; Good, John; Booth, John A.; Lazzarini, Paolo; Fumi, Pierluigi; Anaclerio, Enzo

    2010-07-01

    Hexapods are finding increased use in telescope applications for positioning large payloads. Engineers from The University of Texas at Austin have been working with engineers from ADS International to develop large, high force, highly precise and controllable hexapod actuators for use on the Wide Field Upgrade (WFU) as part of the Hobby Eberly Telescope Dark Energy Experiment (HETDEX)‡. These actuators are installed in a hexapod arrangement, supporting the 3000+ kg instrument payload which includes the Wide Field Corrector (WFC), support structure, and other optical/electronic components. In addition to force capability, the actuators need to meet the tracking speed (pointing) requirements for accuracy and the slewing speed (rewind) requirements, allowing as many observations in one night as possible. The hexapod actuator stroke (retraction and extension) was very closely monitored during the design phase to make sure all of the science requirements could be met, while minimizing the risk of damaging the WFC optical hardware in the unlikely event of a hexapod actuator or controller failure. This paper discusses the design trade-offs between stiffness, safety, back-drivability, accuracy, and leading to selection of the motor, high ratio worm gear, roller screw, coupling, end mounts, and other key components.

  4. Laser guide star adaptive optics: Present and future

    SciTech Connect

    Olivier, S.S.; Max, C.E.

    1993-03-01

    Feasibility demonstrations using one to two meter telescopes have confirmed the utility of laser beacons as wavefront references for adaptive optics systems. Laser beacon architectures suitable for the new generation of eight and ten meter telescopes are presently under study. This paper reviews the concept of laser guide star adaptive optics and the progress that has been made by groups around the world implementing such systems. A description of the laser guide star program at LLNL and some experimental results is also presented.

  5. A Comprehensive Study of ULIRGs in the Herschel Very Wide Field Surveys

    NASA Astrophysics Data System (ADS)

    Yan, Haojing

    Extreme starbursting galaxies exist at all redshifts, and most of them are so heavily obscured by dust that they are Ultra-Luminous InfraRed Galaxies (ULIRGs) while being faint in optical to near-IR. The latest example is at record-high z=6.337, approaching the end of the reionization. There have been numerous suggestions that understanding ULIRG is critical in constructing a comprehensive picture of galaxy formation history. These range from the hypothesis three decades ago that the ULIRG phase is the prelude to QSO and large ellipticals, to the recent tentative evidence that ULIRG could make a large (if not dominant) contribution to the global star formation rate density (GSFRD) at z>1. However, the exact nature of ULIRG and their role in galaxy assembly still remain illusive, largely due to the limited sample size and the severe source confusion problem in the far-IR (FIR). The very wide field surveys by Herschel have provided the best opportunity to date to systematically study ULIRG beyond the local universe, most importantly because of their wide coverage and high sensitivity to probe large volumes to high redshifts and the multiple FIR bands that allow for direct measurement of the IR luminosities. We propose to construct the largest possible ULIRG sample in these fields at all redshifts, and to study the evolution of ULIRGs. We will concentrate on the HerMES, the H-ATLAS and the HerS programs whose data are already public. While the confusion problem still persists in these Herschel data, we have demonstrated that it is possible to directly use the position priors from optical images to decompose the candidate contributors to a given Herschel source if its S/N suffices (Yan et al. 2014). This is a significant improvement over previous studies where higher-resolution mid-IR (mostly Spitzer MIPS 24-micron) data had to be used as the proxies to the FIR source locations, because (1) such proxy images also suffer from the blending problem in the first place and

  6. The Wide-field Imaging Interferometry Testbed (WIIT): recent progress in the simulation and synthesis of WIIT data

    NASA Astrophysics Data System (ADS)

    Juanola-Parramon, Roser; Leisawitz, David T.; Bolcar, Matthew R.; Maher, Stephen F.; Rinehart, Stephen A.; Iacchetta, Alex; Savini, Giorgio

    2016-08-01

    The Wide-field Imaging Interferometry Testbed (WIIT) is a double Fourier (DF) interferometer operating at optical wavelengths, and provides data that are highly representative of those from a space-based far-infrared interferometer like SPIRIT. This testbed has been used to measure both a geometrically simple test scene and an astronomically representative test scene. Here we present the simulation of recent WIIT measurements using FIInS (the Far-infrared Interferometer Instrument Simulator), the main goal of which is to simulate both the input and the output of a DFM system. FIInS has been modified to perform calculations at optical wavelengths and to include an extended field of view due to the presence of a detector array.

  7. Resolving fringe ambiguities of a wide-field Michelson interferometer using visibility measurements of a noncollimated laser beam.

    PubMed

    Wan, Xiaoke; Wang, Ji; Ge, Jian

    2009-09-10

    An actively stabilized interferometer with a constant optical path difference is a key element in long-term astronomical observation, and resolving interference fringe ambiguities is important to produce high-precision results for the long term. We report a simple and reliable method of resolving fringe ambiguities of a wide-field Michelson interferometer by measuring the interference visibility of a noncollimated single-frequency laser beam. Theoretical analysis shows that the interference visibility is sensitive to a subfringe phase shift, and a wide range of beam arrangements is suitable for real implementation. In an experimental demonstration, a Michelson interferometer has an optical path difference of 7 mm and a converging monitoring beam has a numerical aperture of 0.045 with an incidental angle of 17 degrees. The resolution of visibility measurements corresponds to approximately 1/16 fringe in the interferometer phase shift. The fringe ambiguity-free region is extended over a range of approximately 100 fringes.

  8. Wide-field multiphoton imaging of cellular dynamics in thick tissue by temporal focusing and patterned illumination

    PubMed Central

    Therrien, O. D.; Aubé, B.; Pagès, S.; Koninck, P. De; Côté, D.

    2011-01-01

    Wide-field temporal focusing is a novel technique that provides optical sectioning for imaging without the need for beam scanning. However, illuminating over large areas greatly reduces the photon density which limits the technique applicability to small regions, precluding functional imaging of cellular networks. Here we present a strategy that combines beam shaping and temporal focusing of amplified pulses (>1 µJ/pulse) for fast imaging of cells from the central nervous system in acute slices. Multiphoton video-rate imaging over total areas as wide as 4800 µm2 with an optical sectioning under 10 µm at 800 nm is achieved with our setup, leading to imaging of calcium dynamics of multiple cells simultaneously in thick tissue. PMID:21412473

  9. WIDE-FIELD PRECISION KINEMATICS OF THE M87 GLOBULAR CLUSTER SYSTEM

    SciTech Connect

    Strader, Jay; Romanowsky, Aaron J.; Brodie, Jean P.; Beasley, Michael A.; Arnold, Jacob A.; Tamura, Naoyuki; Sharples, Ray M.; Arimoto, Nobuo

    2011-12-01

    We present the most extensive combined photometric and spectroscopic study to date of the enormous globular cluster (GC) system around M87, the central giant elliptical galaxy in the nearby Virgo Cluster. Using observations from DEIMOS and the Low Resolution Imaging Spectrometer at Keck, and Hectospec on the Multiple Mirror Telescope, we derive new, precise radial velocities for 451 GCs around M87, with projected radii from {approx}5 to 185 kpc. We combine these measurements with literature data for a total sample of 737 objects, which we use for a re-examination of the kinematics of the GC system of M87. The velocities are analyzed in the context of archival wide-field photometry and a novel Hubble Space Telescope catalog of half-light radii, which includes sizes for 344 spectroscopically confirmed clusters. We use this unique catalog to identify 18 new candidate ultracompact dwarfs and to help clarify the relationship between these objects and true GCs. We find much lower values for the outer velocity dispersion and rotation of the GC system than in earlier papers and also differ from previous work in seeing no evidence for a transition in the inner halo to a potential dominated by the Virgo Cluster, nor for a truncation of the stellar halo. We find little kinematical evidence for an intergalactic GC population. Aided by the precision of the new velocity measurements, we see significant evidence for kinematical substructure over a wide range of radii, indicating that M87 is in active assembly. A simple, scale-free analysis finds less dark matter within {approx}85 kpc than in other recent work, reducing the tension between X-ray and optical results. In general, out to a projected radius of {approx}150 kpc, our data are consistent with the notion that M87 is not dynamically coupled to the Virgo Cluster; the core of Virgo may be in the earliest stages of assembly.

  10. Wide field imager instrument for the Advanced Telescope for High Energy Astrophysics

    NASA Astrophysics Data System (ADS)

    Meidinger, Norbert; Nandra, Kirpal; Plattner, Markus; Porro, Matteo; Rau, Arne; Santangelo, Andrea; Tenzer, Chris; Wilms, Jörn

    2015-01-01

    The Advanced Telescope for High Energy Astrophysics (Athena) has been selected for ESA's L2 mission, scheduled for launch in 2028. It will provide the necessary capabilities to achieve the ambitious goals of the science theme "The Hot and Energetic Universe." Athena's x-ray mirrors will be based on silicon pore optics technology with a 12-m focal length. Two complementary focal plane camera systems are foreseen, which can be moved interchangeably to the focus of the mirror system: the actively shielded micro-calorimeter spectrometer X-IFU and the wide field imager (WFI). The WFI camera will provide an unprecedented survey power through its large field of view of 40 arc min with a high count-rate capability (˜1 Crab). It permits a state-of-the-art energy resolution in the energy band of 0.1 to 15 keV during the entire mission lifetime (e.g., full width at half maximum ≤150 eV at 6 keV). This performance is accomplished by a set of depleted P-channel field effect transistor (DEPFET) active pixel sensor matrices with a pixel size well suited to the angular resolution of 5 arc sec (on-axis) of the mirror system. Each DEPFET pixel is a combined detector-amplifier structure with a MOSFET integrated onto a fully depleted 450-μm-thick silicon bulk. This manuscript will summarize the current instrument concept and design, the status of the technology development, and the envisaged baseline performance.

  11. Peripheral Reticular Pigmentary Degeneration and Choroidal Vascular Insufficiency, Studied by Ultra Wide-Field Fluorescein Angiography

    PubMed Central

    Bae, Kunho; Cho, Kyuyeon; Kang, Se Woong; Kim, Sang Jin; Kim, Jong Min

    2017-01-01

    Purpose To explore the pathogenesis of peripheral reticular pigmentary degeneration (PRPD) and its clinical significance. Methods This cross-sectional, observational study (conducted between January 2010 and May 2015) enrolled 441 eyes of 229 subjects, including 35 eyes with PRPD and 406 eyes without PRPD, which was identified by ultra-wide-field fluorescein angiography (UWFA). The distribution and angiographic circulation time of PRPD were assessed by UWFA. The frequencies of systemic and ophthalmologic comorbidities were compared between groups. Univariate and multivariate generalized estimation equation methods were used to determine the risk factors for PRPD. Results The patients with PRPD had a mean age of 75.7 ± 8.5 years (range, 59–93 years), whereas the patients without PRPD had a mean age of 60.1 ± 14.9 years (range, 9–92 years). All eyes with PRPD manifested the lesion in the superior nasal periphery with or without circumferential extension. Among those, only 16 eyes (45.7%) in the PRPD group showed distinctive features in the same location on fundus photographs. There was significant choroidal filling delay in the PRPD group when compared with the control group (1.42±1.22 vs. -0.02±1.05 seconds, P < 0.001). Multivariate regression analysis revealed that older age (P < 0.001), stroke (P = 0.018), ischemic optic neuropathy (P < 0.001), and age-related macular degeneration (P = 0.022) were significantly associated with PRPD. Conclusions UWFA may enhance the diagnostic sensitivity of PRPD. Choroidal vascular insufficiency with compromised systemic circulation in the elderly was related to the manifestation of PRPD. These results help to better understand the pathophysiology of PRPD. Co-existence of systemic and ophthalmic circulatory disorders should be considered in patients with PRPD. PMID:28114409

  12. Cone of Darkness: Finding Blank-sky Positions for Multi-object Wide-field Observations

    NASA Astrophysics Data System (ADS)

    Lorente, N. P. F.

    2014-05-01

    We present the Cone of Darkness, an application to automatically configure blank-sky positions for a series of stacked, wide-field observations, such as those carried out by the SAMI instrument on the Anglo-Australian Telescope (AAT). The Sydney-AAO Multi-object Integral field spectrograph (SAMI) uses a plug-plate to mount its 13×61 core imaging fibre bundles (hexabundles) in the optical plane at the telescope's prime focus. To make the most efficient use of each plug-plate, several observing fields are typically stacked to produce a single plate. When choosing blank-sky positions for the observations it is most effective to select these such that one set of 26 holes gives valid sky positions for all fields on the plate. However, when carried out manually this selection process is tedious and includes a significant risk of error. The Cone of Darkness software aims to provide uniform blank-sky position coverage over the field of observation, within the limits set by the distribution of target positions and the chosen input catalogs. This will then facilitate the production of the best representative median sky spectrum for use in sky subtraction. The application, written in C++, is configurable, making it usable for a range of instruments. Given the plate characteristics and the positions of target holes, the software segments the unallocated space on the plate and determines the position which best fits the uniform distribution requirement. This position is checked, for each field, against the selected catalog using a TAP ADQL search. The process is then repeated until the desired number of sky positions is attained.

  13. SuperBIT: Wide-field, Sub-arcsecond Imaging from the Super-Pressure Balloon Platform

    NASA Astrophysics Data System (ADS)

    Jones, William

    The scientific potential of diffraction-limited imaging from mid-latitude ultra-long duration balloon payloads is immense. The combination of diffraction-limited angular resolution, extreme stability, space-like backgrounds, and long integrations enables transformative opportunities in studies ranging from the weak lensing of galaxy clusters and cosmic shear, to the search for exoplanets. Pioneering research, spear-headed by the co-investigators of this proposal, has led to the development of the precision tip/tilt and de-rotation systems that are required to realize the potential of the super-pressure balloon (SPB) platform for deep, wide-field imaging. Under a separately funded Canadian Space Agency program, a half-meter class telescope has been integrated with a prototype sub-arcsecond pointing system. We propose a highly focused five-year program to develop and fly a comparable instrument on the mid-latitude SPB platform, demonstrating the imaging capability during an ultra-long duration balloon flight while providing space-quality weak lensing measurements for a large catalog of galaxy clusters. This instrument will provide imaging with a half-degree field of view and 0.3-arcsecond resolution in five bands between 300 and 1000 nm, with sensitivities in the shape-band exceeding 24th magnitude (> 5 sigma) in 300 seconds of integration. We propose an observing schedule that is split between a performance verification sample, a photometric and spectroscopic calibration set, a deep field, and a science catalog. The performance verification set prioritizes a sample of thirty clusters that have been previously well studied with the HST Advanced Camera for Surveys, the Chandra X-ray observatory, and for which there are Compton-Y parameter data from millimeter wavelengths. The photometric calibration set will be selected from the COSMOS field. The science catalog will draw from a set of more than 150 Sunyaev-Zel'dovich, X-ray, and optically-selected clusters spanning a

  14. Workshop on Future Directions for Optical Information Processing.

    DTIC Science & Technology

    1981-03-01

    preliminary efforts in this direction. Recent work on microcnannel plate optical devices [83,84) and cellular liquid crystal systems [85) also show promise...00000000000000000000000 00 1 1 11 111111 11111 1111 0000000000000 000000 0 000 aecio HOW matl cylz - 1 SECTOR ROM INVERT CICLS - 21 Figuro 18 Bias Customizing Pattern

  15. Ground-based astrometry with wide field imagers. V. Application to near-infrared detectors: HAWK-I@VLT/ESO

    NASA Astrophysics Data System (ADS)

    Libralato, M.; Bellini, A.; Bedin, L. R.; Piotto, G.; Platais, I.; Kissler-Patig, M.; Milone, A. P.

    2014-03-01

    High-precision astrometry requires accurate point-spread function modeling and accurate geometric-distortion corrections. This paper demonstrates that it is possible to achieve both requirements with data collected at the high acuity wide-field K-band imager (HAWK-I), a wide-field imager installed at the Nasmyth focus of UT4/VLT ESO 8 m telescope. Our final astrometric precision reaches ~3 mas per coordinate for a well-exposed star in a single image with a systematic error less than 0.1 mas. We constructed calibrated astro-photometric catalogs and atlases of seven fields: the Baade's window, NGC 6656, NGC 6121, NGC 6822, NGC 6388, NGC 104, and the James Webb Space Telescope calibration field (in the Large Magellanic Cloud). We make these catalogs and images electronically available to the community. Furthermore, as a demonstration of the efficacy of our approach, we combined archival material taken with the optical wide-field imager at the MPI/ESO 2.2 m with HAWK-I observations. We showed that we are able to achieve an excellent separation between cluster members and field objects for NGC 6656 and NGC 6121 with a time base-line of about 8 years. Using both HST and HAWK-I data, we also study the radial distribution of the SGB populations in NGC 6656 and conclude that the radial trend is flat within our uncertainty. We also provide membership probabilities for most of the stars in NGC 6656 and NGC 6121 catalogs and estimate membership for the published variable stars in these two fields. Catalogs, fortran code, and distortion maps are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/563/A80Based on observations with the 8 m VLT ESO telescope.

  16. UVUDF: Ultraviolet imaging of the Hubble ultra deep field with wide-field camera 3

    SciTech Connect

    Teplitz, Harry I.; Rafelski, Marc; Colbert, James W.; Hanish, Daniel J.; Kurczynski, Peter; Gawiser, Eric; Bond, Nicholas A.; Gardner, Jonathan P.; De Mello, Duilia F.; Grogin, Norman; Koekemoer, Anton M.; Brown, Thomas M.; Coe, Dan; Ferguson, Henry C.; Atek, Hakim; Finkelstein, Steven L.; Giavalisco, Mauro; Gronwall, Caryl; Lee, Kyoung-Soo; Ravindranath, Swara; and others

    2013-12-01

    We present an overview of a 90 orbit Hubble Space Telescope treasury program to obtain near-ultraviolet imaging of the Hubble Ultra Deep Field using the Wide Field Camera 3 UVIS detector with the F225W, F275W, and F336W filters. This survey is designed to: (1) investigate the episode of peak star formation activity in galaxies at 1 < z < 2.5; (2) probe the evolution of massive galaxies by resolving sub-galactic units (clumps); (3) examine the escape fraction of ionizing radiation from galaxies at z ∼ 2-3; (4) greatly improve the reliability of photometric redshift estimates; and (5) measure the star formation rate efficiency of neutral atomic-dominated hydrogen gas at z ∼ 1-3. In this overview paper, we describe the survey details and data reduction challenges, including both the necessity of specialized calibrations and the effects of charge transfer inefficiency. We provide a stark demonstration of the effects of charge transfer inefficiency on resultant data products, which when uncorrected, result in uncertain photometry, elongation of morphology in the readout direction, and loss of faint sources far from the readout. We agree with the STScI recommendation that future UVIS observations that require very sensitive measurements use the instrument's capability to add background light through a 'post-flash'. Preliminary results on number counts of UV-selected galaxies and morphology of galaxies at z ∼ 1 are presented. We find that the number density of UV dropouts at redshifts 1.7, 2.1, and 2.7 is largely consistent with the number predicted by published luminosity functions. We also confirm that the image mosaics have sufficient sensitivity and resolution to support the analysis of the evolution of star-forming clumps, reaching 28-29th magnitude depth at 5σ in a 0.''2 radius aperture depending on filter and observing epoch.

  17. Wavelet image processing applied to optical and digital holography: past achievements and future challenges

    NASA Astrophysics Data System (ADS)

    Jones, Katharine J.

    2005-08-01

    The link between wavelets and optics goes back to the work of Dennis Gabor who both invented holography and developed Gabor decompositions. Holography involves 3-D images. Gabor decompositions involves 1-D signals. Gabor decompositions are the predecessors of wavelets. Wavelet image processing of holography, both optical holography and digital holography, will be examined with respect to past achievements and future challenges.

  18. Novel wide-field-of-view laser retroreflector for the Space Interferometry Mission

    NASA Astrophysics Data System (ADS)

    Schmidtlin, Edouard G.; Shaklan, Stuart B.; Carlson, Andrew E.

    1998-07-01

    A new type of laser retroreflector has been developed for JPL's future Space Interferometry Mission. The retroreflector consists of an assembly of prisms of form multiple hollow cornercubes. This allows the limited field of view of about 60 degrees of a single corner can be overcome, to comply with the geometry of an optical truss. In addition, an innovative feature is that the retroreflector has common vertices, in order to define a single point optical fiducial necessary for point-to-point 3D laser metrology. The multiple cornercube provides better thermal stability and optical performance than spherical and hemispherical type retroreflectors. In manufacturing the prototype, the key technology of assembling prisms to the interferometric accuracy has been demonstrated. A non common vertex error of a few micrometers has been achieved.

  19. THE FIRST HUNDRED BROWN DWARFS DISCOVERED BY THE WIDE-FIELD INFRARED SURVEY EXPLORER (WISE)

    SciTech Connect

    Davy Kirkpatrick, J.; Gelino, Christopher R.; Griffith, Roger L.; Marsh, Kenneth A.; Tsai, Chao-Wei; Beichman, Charles A.; Cushing, Michael C.; Mainzer, A.; Eisenhardt, Peter R.; Bauer, James M.; Skrutskie, Michael F.; Wright, Edward L.; McLean, Ian S.; Lake, Sean E.; Petty, Sara M.; Thompson, Maggie A.; Benford, Dominic J.; Bridge, Carrie R.; Stanford, S. A.; Bailey, Vanessa; and others

    2011-12-01

    We present ground-based spectroscopic verification of 6 Y dwarfs (see also Cushing et al.), 89 T dwarfs, 8 L dwarfs, and 1 M dwarf identified by the Wide-field Infrared Survey Explorer (WISE). Eighty of these are cold brown dwarfs with spectral types {>=}T6, six of which have been announced earlier by Mainzer et al. and Burgasser et al. We present color-color and color-type diagrams showing the locus of M, L, T, and Y dwarfs in WISE color space. Near-infrared and, in a few cases, optical spectra are presented for these discoveries. Near-infrared classifications as late as early Y are presented and objects with peculiar spectra are discussed. Using these new discoveries, we are also able to extend the optical T dwarf classification scheme from T8 to T9. After deriving an absolute WISE 4.6 {mu}m (W2) magnitude versus spectral type relation, we estimate spectrophotometric distances to our discoveries. We also use available astrometric measurements to provide preliminary trigonometric parallaxes to four of our discoveries, which have types of L9 pec (red), T8, T9, and Y0; all of these lie within 10 pc of the Sun. The Y0 dwarf, WISE 1541-2250, is the closest at 2.8{sup +1.3}{sub -0.6} pc; if this 2.8 pc value persists after continued monitoring, WISE 1541-2250 will become the seventh closest stellar system to the Sun. Another 10 objects, with types between T6 and >Y0, have spectrophotometric distance estimates also placing them within 10 pc. The closest of these, the T6 dwarf WISE 1506+7027, is believed to fall at a distance of {approx}4.9 pc. WISE multi-epoch positions supplemented with positional info primarily from the Spitzer/Infrared Array Camera allow us to calculate proper motions and tangential velocities for roughly one-half of the new discoveries. This work represents the first step by WISE to complete a full-sky, volume-limited census of late-T and Y dwarfs. Using early results from this census, we present preliminary, lower limits to the space density of

  20. The WSRT wide-field H I survey. I. The background galaxy sample

    NASA Astrophysics Data System (ADS)

    Braun, R.; Thilker, D.; Walterbos, R. A. M.

    2003-08-01

    We have used the Westerbork array to carry out an unbiased wide-field survey for H I emission features, achieving an RMS sensitivity of about 18 mJy/Beam at a velocity resolution of 17 km s-1 over 1800 deg2 and between -1000 < VHel <+6500 km s-1. The primary data consists of auto-correlation spectra with an effective angular resolution of 49' FWHM, although cross-correlation data were also acquired. The survey region is centered approximately on the position of Messier 31 and is Nyquist-sampled over 60x 30o in RA x Dec. More than 100 distinct features are detected at high significance in each of the two velocity regimes (negative and positive LGSR velocities). In this paper we present the results for our H I detections of external galaxies at positive LGSR velocity. We detect 155 external galaxies in excess of 8sigma in integrated H I flux density. Plausible optical associations are found within a 30' search radius for all but one of our H I detections in DSS images, although several are not previously cataloged or do not have published red-shift determinations. Our detection without a DSS association is at low galactic latitude. Twenty-three of our objects are detected in H I for the first time. We classify almost half of our detections as ``confused'', since one or more companions is cataloged within a radius of 30' and a velocity interval of 400 km s-1. We identify a handful of instances of significant positional offsets exceeding 10 kpc of unconfused optical galaxies with the associated H I centroid, possibly indicative of severe tidal distortions or uncataloged gas-rich companions. A possible trend is found for an excess of detected H I flux in unconfused galaxies within our large survey beam relative to that detected previously in smaller telescope beams, both as function of increasing distance and increasing gas mass. This may be an indication for a diffuse gaseous component on 100 kpc scales in the environment of massive galaxies or a population of

  1. Novel optical gyroscope: proof of principle demonstration and future scope

    NASA Astrophysics Data System (ADS)

    Srivastava, Shailesh; Rao D. S., Shreesha; Nandakumar, Hari

    2016-10-01

    We report the first proof-of-principle demonstration of the resonant optical gyroscope with reflector that we have recently proposed. The device is very different from traditional optical gyroscopes since it uses the inherent coupling between the clockwise and counterclockwise propagating waves to sense the rotation. Our demonstration confirms our theoretical analysis and simulations. We also demonstrate a novel method of biasing the gyroscope using orthogonal polarization states. The simplicity of the structure and the readout method, the theoretically predicted high sensitivities (better than 0.001 deg/hr), and the possibility of further performance enhancement using a related laser based active device, all have immense potential for attracting fresh research and technological initiatives.

  2. Novel optical gyroscope: proof of principle demonstration and future scope.

    PubMed

    Srivastava, Shailesh; Rao D S, Shreesha; Nandakumar, Hari

    2016-10-03

    We report the first proof-of-principle demonstration of the resonant optical gyroscope with reflector that we have recently proposed. The device is very different from traditional optical gyroscopes since it uses the inherent coupling between the clockwise and counterclockwise propagating waves to sense the rotation. Our demonstration confirms our theoretical analysis and simulations. We also demonstrate a novel method of biasing the gyroscope using orthogonal polarization states. The simplicity of the structure and the readout method, the theoretically predicted high sensitivities (better than 0.001 deg/hr), and the possibility of further performance enhancement using a related laser based active device, all have immense potential for attracting fresh research and technological initiatives.

  3. Novel optical gyroscope: proof of principle demonstration and future scope

    PubMed Central

    Srivastava, Shailesh; Rao D. S., Shreesha; Nandakumar, Hari

    2016-01-01

    We report the first proof-of-principle demonstration of the resonant optical gyroscope with reflector that we have recently proposed. The device is very different from traditional optical gyroscopes since it uses the inherent coupling between the clockwise and counterclockwise propagating waves to sense the rotation. Our demonstration confirms our theoretical analysis and simulations. We also demonstrate a novel method of biasing the gyroscope using orthogonal polarization states. The simplicity of the structure and the readout method, the theoretically predicted high sensitivities (better than 0.001 deg/hr), and the possibility of further performance enhancement using a related laser based active device, all have immense potential for attracting fresh research and technological initiatives. PMID:27694987

  4. Optical coherence elastography: current status and future applications

    NASA Astrophysics Data System (ADS)

    Sun, Cuiru; Standish, Beau; Yang, Victor X. D.

    2011-04-01

    Optical coherence tomography (OCT) has several advantages over other imaging modalities, such as angiography and ultrasound, due to its inherently high in vivo resolution, which allows for the identification of morphological tissue structures. Optical coherence elastography (OCE) benefits from the superior spatial resolution of OCT and has promising applications, including cancer diagnosis and the detailed characterization of arterial wall biomechanics, both of which are based on the elastic properties of the tissue under investigation. We present OCE principles based on techniques associated with static and dynamic tissue excitation, and their corresponding elastogram image-reconstruction algorithms are reviewed. OCE techniques, including the development of intravascular- or catheter-based OCE, are in their early stages of development but show great promise for surgical oncology or intravascular cardiology applications.

  5. A multichannel fiber optic photometer present performance and future developments

    NASA Technical Reports Server (NTRS)

    Barwig, H.; Schoembs, R.; Huber, G.

    1988-01-01

    A three channel photometer for simultaneous multicolor observations was designed with the aim of making possible highly efficient photometry of fast variable objects like cataclysmic variables. Experiences with this instrument over a period of three years are presented. Aspects of the special techniques applied are discussed with respect to high precision photometry. In particular, the use of fiber optics is critically analyzed. Finally, the development of a new photometer concept is discussed.

  6. Optical thin-film technology: past, present, future

    NASA Astrophysics Data System (ADS)

    Strickland, William P.

    1990-12-01

    The evolution of the vacuum coating industry is reviewed. Vacuum science progressed slowly until the late nineteenth century due to an incomplete understanding of vacuum and lack of applications. Edison's invention of the light bulb launched the vacuum industry and increased developmentof improved vacuum systems. The thin film optical coating industry arose from the needs of the German and U.S. military efforts during World War II. The author presents his experience in thin film coating from 1939 to the present.

  7. Upconverting nanoparticles: a versatile platform for wide-field two-photon microscopy and multi-modal in vivo imaging.

    PubMed

    Park, Yong Il; Lee, Kang Taek; Suh, Yung Doug; Hyeon, Taeghwan

    2015-03-21

    Lanthanide-doped upconverting nanoparticles (UCNPs) have recently attracted enormous attention in the field of biological imaging owing to their unique optical properties: (1) efficient upconversion photoluminescence, which is intense enough to be detected at the single-particle level with a (nonscanning) wide-field microscope setup equipped with a continuous wave (CW) near-infrared (NIR) laser (980 nm), and (2) resistance to photoblinking and photobleaching. Moreover, the use of NIR excitation minimizes adverse photoinduced effects such as cellular photodamage and the autofluorescence background. Finally, the cytotoxicity of UCNPs is much lower than that of other nanoparticle systems. All these advantages can be exploited simultaneously without any conflicts, which enables the establishment of a novel UCNP-based platform for wide-field two-photon microscopy. UCNPs are also useful for multimodal in vivo imaging because simple variations in the composition of the lattice atoms and dopant ions integrated into the particles can be easily implemented, yielding various distinct biomedical activities relevant to magnetic resonance imaging (MRI), computed tomography (CT), and positron emission tomography (PET). These multiple functions embedded in a single type of UCNPs play a crucial role in precise disease diagnosis. The application of UCNPs is extended to therapeutic fields such as photodynamic and photothermal cancer therapies through advanced surface conjugation schemes.

  8. Time-resolved hyperspectral single-pixel camera implementation for compressive wide-field fluorescence lifetime imaging

    NASA Astrophysics Data System (ADS)

    Pian, Qi; Yao, Ruoyang; Intes, Xavier

    2016-03-01

    Single-pixel imaging based on compressive sensing theory has been a highlighted technique in the biomedical imaging field for many years. This interest has been driven by the possibility of performing microscopic or macroscopic imaging based on low-cost detector arrays, increased SNR (signal-to-noise ratio) in the acquired data sets and the ability to perform high quality image reconstruction with compressed data sets by exploiting signal sparsity. In this work, we present our recent work in implementing this technique to perform time domain fluorescence-labeled investigations in preclinical settings. More precisely, we report on our time-resolved hyperspectral single-pixel camera for fast, wide-field mapping of molecular labels and lifetime-based quantification. The hyperspectral single-pixel camera implements a DMD (Digital micro-mirror device) to generate optical masks for modulating the illumination field before it is delivered onto the sample and focuses the emission light signals into a multi-anode hyperspectral time-resolved PMT (Photomultiplier tube) to acquire spatial, temporal and spectral information enriched 4-D data sets. Fluorescence dyes with lifetime and spectral contrast are embedded in well plates and thin tissues. L-1 norm based regularization or the least square method, is applied to solve the underdetermined inverse problem during image reconstruction. These experimental results prove the possibility of fast, wide-field mapping of fluorescent labels with lifetime and spectral contrast in thin media.

  9. Spectral wide-field microscopic fluorescence resonance energy transfer imaging in live cells.

    PubMed

    Zhang, Lili; Qin, Guiqi; Chai, Liuying; Zhang, Jiang; Yang, Fangfang; Yang, Hongqin; Xie, Shusen; Chen, Tongsheng

    2015-08-01

    With its precise, sensitive, and nondestructive features, spectral unmixing-based fluorescence resonance energy transfer (FRET) microscopy has been widely applied to visualize intracellular biological events. In this report, we set up a spectral wide-field microscopic FRET imaging system by integrating a varispec liquid crystal tunable filter into a wide-field microscope for quantitative FRET measurement in living cells. We implemented a representative emission-spectral unmixing-based FRET measurement method on this platform to simultaneously acquire pixel-to-pixel images of both FRET efficiency (E ) and acceptor-to-donor concentration ratio (R C ) in living HepG2 cells expressing fusion proteins in the presence or absence of free donors and acceptors and obtained consistent results with other instruments and methods. This stable and low-cost spectral wide-field microscopic FRET imaging system provides a new toolbox for imaging molecular events with high spatial resolution in living cells.

  10. Depth-resolved incoherent and coherent wide-field high-content imaging (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    So, Peter T.

    2016-03-01

    Recent advances in depth-resolved wide-field imaging technique has enabled many high throughput applications in biology and medicine. Depth resolved imaging of incoherent signals can be readily accomplished with structured light illumination or nonlinear temporal focusing. The integration of these high throughput systems with novel spectroscopic resolving elements further enable high-content information extraction. We will introduce a novel near common-path interferometer and demonstrate its uses in toxicology and cancer biology applications. The extension of incoherent depth-resolved wide-field imaging to coherent modality is non-trivial. Here, we will cover recent advances in wide-field 3D resolved mapping of refractive index, absorbance, and vibronic components in biological specimens.

  11. [Past, present, and future in Leber's hereditary optic neuropathy].

    PubMed

    Oguchi, Y

    2001-12-01

    Leber's disease is a disease of optic atrophy first reported by Theodor Leber in 1871. Since then, 130 years have passed. Recently, several new findings about the pathology, causes, and heredity of this disease have been made. In 1988 Wallace and others reported a new mutation of 11778 base pairs of mtDNA of patients with Leber's disease. Since then, the study of this disease has progressed remarkably. In this review clinical studies on Leber's disease which were carried out in our department from 1990 are summarized. 1. Genetic diagnosis and clinics Two hundred and twenty-four cases were examined, including patients at our hospital, for the 8 years between 1990 and 1998. Among them, 72 cases were diagnosed as Leber's disease. There were 3 cases (4%) of 3460 mutations, 63 cases(83%) of 11778 mutations, and 6 cases(8%) of 14484 mutations as primary mutations. The reasons for performing the genetic diagnosis were mostly the need for a definite diagnosis of Leber's disease and research on the genesis of optic nerve atrophy of unknown origin. Concerning the secondary mutations, it was confirmed that these mutations were polymorphic as seen in European and American patients. There is a problem of heteroplasmy about the mtDNA mutation. We developed a simple and exact method to evaluate heteroplasmy by using polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP). In a study of peripheral blood samples in one family, Leber's disease does not appear under conditions of less than 60% mtDNA mutation. As for the three kinds of mutation in Leber's disease, cases of recovery of a visual acuity of 0.3 and above were only 7% in 11778 mutations, but 38% in 3460 mutations and 50% in 14484 mutations. It is assumed that visual prognosis depends on the kind of mutation. 2. Characteristics of visual evoked potential(VEP) In pattern VEP in the acute stage, latency was not delayed very much, but the amplitude was low. On the other hand, in the acute stage of optic

  12. Architectural Options for a Future Deep Space Optical Communications Network

    NASA Technical Reports Server (NTRS)

    Edwards, B. L.; Benjamin, T.; Scozzafava, J.; Khatri, F.; Sharma, J.; Parvin, B.; Liebrecht, P. E.; Fitzgerald, R. J.

    2004-01-01

    This paper provides an overview of different options at Earth to provide Deep Space optical communication services. It is based mainly on work done for the Mars Laser Communications Demonstration (MLCD) Project, a joint project between NASA's Goddard Space Flight Center (GSFC), the Jet Propulsion Laboratory, California Institute of Technology (JPL), and the Massachusetts Institute of Technology Lincoln Laboratory (MIT/LL). It also reports preliminary conclusions from the Tracking and Data Relay Satellite System Continuation Study at GSFC. A lasercom flight terminal will be flown on the Mars Telecommunications Orbiter (MTO) to be launched by NASA in 2009, and will be the first high rate deep space demonstration of this revolutionary technology.

  13. Experiments with "wide field" for Space Surveillance Systems in Odessa Astronomical observatory (Ukraine). Prodolzhen eksperiment s "shirokim polem" dlya zadach kontrolya kosmicheskogo prostranstva v Odesskoy astronomicheskoy observatorii

    NASA Astrophysics Data System (ADS)

    Sukhov, P. P.

    2007-08-01

    In OAO on point Mayaki (40 km for city) is continued observations geostationary (GSS) and low orbital (LEO) satellites with using more inexpensive domestic, "ready to use", wide field optic lens for the reason: To get limited magnitude on high orbital cosmic object (HEO) to 15m in to view telescope 3 -7 degrees for time accumulation 10-15 sec. To value the possibility of the use WFO for monitoring LEO on low orbit by height less than 2 000 km with limited magnitude to 11m on star for 1 sec. accumulations. 90% LEO from 39 objects are surely identified using catalog NORAD. About obtain the results possible to read in article: "About using wide field lens optics for Space Surveillance Systems in Odessa Astronomical observatory" (in Russian).

  14. Fabrication of a wide-field NIR integral field unit for SWIMS using ultra-precision cutting

    NASA Astrophysics Data System (ADS)

    Kitagawa, Yutaro; Yamagata, Yutaka; Morita, Shin-ya; Motohara, Kentaro; Ozaki, Shinobu; Takahashi, Hidenori; Konishi, Masahiro; Kato, Natsuko M.; Kobayakawa, Yutaka; Terao, Yasunori; Ohashi, Hirofumi

    2016-07-01

    We describe overview of fabrication methods and measurement results of test fabrications of optical surfaces for an integral field unit (IFU) for Simultaneous color Wide-field Infrared Multi-object Spectrograph, SWIMS, which is a first-generation instrument for the University of Tokyo Atacama Observatory 6.5-m telescope. SWIMS-IFU provides entire near-infrared spectrum from 0.9 to 2.5 μm simultaneously covering wider field of view of 17" × 13" compared with current near-infrared IFUs. We investigate an ultra-precision cutting technique to monolithically fabricate optical surfaces of IFU optics such as an image slicer. Using 4- or 5-axis ultra precision machine we compare the milling process and shaper cutting process to find the best way of fabrication of image slicers. The measurement results show that the surface roughness almost satisfies our requirement in both of two methods. Moreover, we also obtain ideal surface form in the shaper cutting process. This method will be adopted to other mirror arrays (i.e. pupil mirror and slit mirror, and such monolithic fabrications will also help us to considerably reduce alignment procedure of each optical elements.

  15. Sampling and Analysis of Impact Crater Residues found on the Wide Field Planetary Camera-2 Radiator

    NASA Technical Reports Server (NTRS)

    Kearsley, A. T.; Grime, G. W.; Colaux, J. L.; Jeynes, C.; Palitsin, V. V.; Webb, R. P.; Griffin, T. J.; Reed, B. B.; Anz-Meador, P. D.; Kou, J.-C.; Robinson, G. A.; Opiela, J. N.; Gerlach, L.

    2013-01-01

    After nearly 16 years on orbit, the Wide Field Planetary Camera-2 (WFPC-2) was recovered from the Hubble Space Telescope in May 2009 during the 12 day shuttle mission designated STS-125. During that exposure to the low Earth orbit environment, the WFPC-2 radiator was struck by approximately 700 impactors producing crater features 300 micrometers and larger in size. Following an optical inspection of these features in 2009, an agreement was reached for the joint NASA-ESA examination and characterization of crater residues, the remnants of the projectile, in 2011. Active examination began in 2012, with 486 of the impact features being cored at NASA Johnson Space Center fs (JSC) Space Exposed Hardware cleanroom and curation facility. The core samples were subsequently divided between NASA and ESA. NASA's analysis was conducted at JSC fs Astromaterials Research and Exploration Science (ARES) Division, using scanning electron microscopy (SEM)/ energy dispersive X-ray spectrometry (EDS) methods, and ESA's analysis was conducted at the Natural History Museum (NHM) again using SEM/EDS, and at the University of Surrey Ion Beam Centre (IBC) using ion beam analysis (IBA) with a scanned proton microbeam. As detailed discussion of the joint findings remains premature at this point, this paper reports on the coring technique developed; the practical taxonomy developed to classify residues as belonging either to anthropogenic "orbital debris" or micrometeoroids; and the protocols for examination of crater residues. Challenges addressed in coring were the relative thickness of the surface to be cut, protection of the impact feature from contamination while coring, and the need to preserve the cleanroom environment so as to preclude or minimize cross-contamination. Classification criteria are summarized, including the assessment of surface contamination and surface cleaning. Finally, we discuss the analytical techniques used to examine the crater residues. We employed EDS from

  16. Nanosecond time-scale switching of permalloy thin film elements studied by wide-field time-resolved Kerr microscopy

    NASA Astrophysics Data System (ADS)

    Chumakov, Dmitry; McCord, Jeffrey; Schäfer, Rudolf; Schultz, Ludwig; Vinzelberg, Hartmut; Kaltofen, Rainer; Mönch, Ingolf

    2005-01-01

    The switching of extended Ni81Fe19 thin film elements with a thickness of 50nm and various shapes (squared, rectangular, pointed) has been studied by time-resolved stroboscopic Kerr microscopy based on a conventional wide-field optical polarization microscope. The elements are deposited on coplanar strip-lines that generate field pulses driven by electronic pulse generators. Time resolution is obtained by imaging with a gated and intensified charge-coupled device camera. The opening can be varied from 250ps to continuous exposure, allowing the comparison of fast magnetization processes and quasistatic switching in slowly varying fields. The latter is typically characterized by the formation of a concertina domain pattern that irreversibly decays in a multidomain ground state by the abrupt motion of vortices and domain walls. After excitation with fast field pulses similar blocked patterns are formed. They dissolve by spatially inhomogeneous rotational processes involving cross-tie-wall-like domain boundaries.

  17. ISS-Lobster: a low-cost wide-field X-ray transient detector on the ISS

    NASA Astrophysics Data System (ADS)

    Petre, Robert; Camp, Jordan; Barthelmy, Scott; Gehrels, Neil; Racusin, Judith; Marshall, Frank; Ptak, Andrew

    2015-04-01

    ISS-Lobster is a wide-field X-ray transient detector proposed to be deployed on the International Space Station. Through its unique imaging X-ray optics that allow a 30 deg by 30 deg FoV, a 1 arc min position resolution and a 10-11 erg/(sec cm2) sensitivity in 2000 sec, ISS-Lobster will observe numerous events per year of X-ray transients related to compact objects, including: tidal disruptions of stars, supernova shock breakouts, neutron star bursts and superbursts, high redshift Gamma-Ray Bursts, and perhaps most exciting, X-ray counterparts of gravitational wave detections involving stellar mass and possibly supermassive black holes. The mission includes a 3-axis gimbal system that allows fast Target of Opportunity pointing, and a small gamma-ray burst monitor to be contributed by the Technion (Israel Institute of Technology).

  18. Mini-MegaTORTORA wide-field monitoring system with sub-second temporal resolution: observation of transient events

    NASA Astrophysics Data System (ADS)

    Karpov, S.; Beskin, G.; Biryukov, A.; Bondar, S.; Ivanov, E.; Katkova, E.; Perkov, A.; Sasyuk, V.

    2016-06-01

    Here we present a summary of first years of operation and first results of a novel 9-channel wide-field optical monitoring system with sub-second temporal resolution, Mini-MegaTORTORA (MMT-9), which is in operation now at Special Astrophysical Observatory on Russian Caucasus. The system is able to observe the sky simultaneously in either wide (~900 square degrees) or narrow (~100 square degrees) fields of view, either in clear light or with any combination of color (Johnson-Cousins B, V or R) and polarimetric filters installed, with exposure times ranging from 0.1 s to hundreds of seconds. The real-time system data analysis pipeline performs automatic detection of rapid transient events, both near-Earth and extragalactic. The objects routinely detected by MMT include faint meteors and artificial satellites. The pipeline for a longer time scales variability analysis is still in development.

  19. KOALA: a wide-field 1000 element integral-field unit for the Anglo-Australian Telescope

    NASA Astrophysics Data System (ADS)

    Ellis, S. C.; Ireland, M.; Lawrence, J. S.; Tims, J.; Staszak, N.; Brzeski, J.; Parker, Q. A.; Sharp, R.; Bland-Hawthorn, J.; Case, S.; Colless, M.; Croom, S.; Couch, W.; De Marco, O.; Glazebrook, K.; Saunders, W.; Webster, R.; Zucker, D. B.

    2012-09-01

    KOALA, the Kilofibre Optimised Astronomical Lenslet Array, is a wide-field, high efficiency integral field unit being designed for use with the bench mounted AAOmega spectrograph on the AAT. KOALA will have 1000 fibres in a rectangular array with a selectable field of view of either 1390 or 430 sq. arcseconds with a spatial sampling of 1.25" or 0.7" respectively. To achieve this KOALA will use a telecentric double lenslet array with interchangeable fore-optics. The IFU will feed AAOmega via a 31m fibre run. The efficiency of KOALA is expected to be ≍ 52% at 3700A and ≍ 66% at 6563°Å with a throughput of > 52% over the entire wavelength range.

  20. Mini-Mega-TORTORA wide-field monitoring system with sub-second temporal resolution: first year of operation

    NASA Astrophysics Data System (ADS)

    Karpov, S.; Beskin, G.; Biryukov, A.; Bondar, S.; Ivanov, E.; Katkova, E.; Perkov, A.; Sasyuk, V.

    2016-12-01

    Here we present the summary of first years of operation and the first results of a novel 9-channel wide-field optical monitoring system with sub-second temporal resolution, Mini-Mega-TORTORA (MMT-9), which is in operation now at Special Astrophysical Observatory on Russian Caucasus. The system is able to observe the sky simultaneously in either wide (˜900 square degrees) or narrow (˜100 square degrees) fields of view, either in clear light or with any combination of color (Johnson-Cousins B, V or R) and polarimetric filters installed, with exposure times ranging from 0.1 s to hundreds of seconds. The real-time system data analysis pipeline performs automatic detection of rapid transient events, both near-Earth and extragalactic. The objects routinely detected by MMT include faint meteors and artificial satellites. The pipeline for a longer time scales variability analysis is still in development.

  1. Mathematical Design Optimization of Wide-Field X-ray Telescopes: Mirror Nodal Positions and Detector Tilts

    NASA Technical Reports Server (NTRS)

    Elsner, R. F.; O'Dell, S. L.; Ramsey, B. D.; Weisskopf, M. C.

    2011-01-01

    We describe a mathematical formalism for determining the mirror shell nodal positions and detector tilts that optimize the spatial resolution averaged over a field-of-view for a nested x-ray telescope, assuming known mirror segment surface prescriptions and known detector focal surface. The results are expressed in terms of ensemble averages over variable combinations of the ray positions and wave vectors in the flat focal plane intersecting the optical axis at the nominal on-axis focus, which can be determined by Monte-Carlo ray traces of the individual mirror shells. This work is part of our continuing efforts to provide analytical tools to aid in the design process for wide-field survey x-ray astronomy missions.

  2. Micrometeoroid Impacts on the Hubble Sace Telescope Wide Field and Planetary Camera 2: Ion Beam Analysis of Subtle Impactor Traces

    NASA Technical Reports Server (NTRS)

    Grime, G. W.; Webb, R. P.; Jeynes, C.; Palitsin, V. V.; Colaux, J. L.; Kearsley, A. T.; Ross, D. K.; Anz-Meador, P.; Liou, J. C.; Opiela, J.; Griffin, T.; Gerlach, L.; Wozniakiewicz, P. J.; Price, M. C.; Burchell, M. J.; Cole, M. J.

    2014-01-01

    Recognition of origin for particles responsible for impact damage on spacecraft such as the Hubble Space Telescope (HST) relies upon postflight analysis of returned materials. A unique opportunity arose in 2009 with collection of the Wide Field and Planetary Camera 2 (WFPC2) from HST by shuttle mission STS-125. A preliminary optical survey confirmed that there were hundreds of impact features on the radiator surface. Following extensive discussion between NASA, ESA, NHM and IBC, a collaborative research program was initiated, employing scanning electron microscopy (SEM) and ion beam analysis (IBA) to determine the nature of the impacting grains. Even though some WFPC2 impact features are large, and easily seen without the use of a microscope, impactor remnants may be hard to find.

  3. Mathematical Design Optimization of Wide-Field X-ray Telescopes: Mirror Nodal Positions and Detector Tilts

    NASA Technical Reports Server (NTRS)

    Elsner, Ronald; O'Dell, Stephen; Ramsey, Brian; Weisskopf, Martin

    2011-01-01

    We describe a mathematical formalism for determining the mirror shell nodal positions and detector tilts that optimize the spatial resolution averaged over a field-of-view for a nested x-ray telescope, assuming known mirror segment surface prescriptions and known detector focal surface. The results are expressed in terms of ensemble averages over variable combinations of the ray positions and wavevectors in the flat focal plane intersecting the optical axis at the nominal on-axis focus, which can be determined by Monte-Carlo ray traces of the individual mirror shells. This work is part of our continuing efforts to provide analytical tools to aid in the design process for wide-field survey x-ray astronomy missions.

  4. A low-cost and versatile system for projecting wide-field visual stimuli within fMRI scanners

    PubMed Central

    Greco, V.; Frijia, F.; Mikellidou, K.; Montanaro, D.; Farini, A.; D’Uva, M.; Poggi, P.; Pucci, M.; Sordini, A.; Morrone, M. C.; Burr, D. C.

    2016-01-01

    We have constructed and tested a custom-made magnetic-imaging-compatible visual projection system designed to project on a very wide visual field (~80°). A standard projector was modified with a coupling lens, projecting images into the termination of an image fiber. The other termination of the fiber was placed in the 3-T scanner room with a projection lens, which projected the images relayed by the fiber onto a screen over the head coil, viewed by a participant wearing magnifying goggles. To validate the system, wide-field stimuli were presented in order to identify retinotopic visual areas. The results showed that this low-cost and versatile optical system may be a valuable tool to map visual areas in the brain that process peripheral receptive fields. PMID:26092392

  5. A low-cost and versatile system for projecting wide-field visual stimuli within fMRI scanners.

    PubMed

    Greco, V; Frijia, F; Mikellidou, K; Montanaro, D; Farini, A; D'Uva, M; Poggi, P; Pucci, M; Sordini, A; Morrone, M C; Burr, D C

    2016-06-01

    We have constructed and tested a custom-made magnetic-imaging-compatible visual projection system designed to project on a very wide visual field (~80°). A standard projector was modified with a coupling lens, projecting images into the termination of an image fiber. The other termination of the fiber was placed in the 3-T scanner room with a projection lens, which projected the images relayed by the fiber onto a screen over the head coil, viewed by a participant wearing magnifying goggles. To validate the system, wide-field stimuli were presented in order to identify retinotopic visual areas. The results showed that this low-cost and versatile optical system may be a valuable tool to map visual areas in the brain that process peripheral receptive fields.

  6. Estimating crop production in Iowa from Advanced Wide Field Sensor (AWiFS) data

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Indian National Remote Sensing Agency ResourceSat-1 Advanced Wide Field Sensor (AWiFS) data for the USA is being provided online by the USDA Foreign Agricultural Service (FAS) and Arctic Slope Regional Corporation – Management Services (ASRC-MS). Because of the frequent revisit time and pixel sizes...

  7. Astronaut Jeffrey Hoffman with Wide Field/Planetary Camera during EVA

    NASA Technical Reports Server (NTRS)

    1993-01-01

    Astronaut Jeffrey A. Hoffman with Wide Field/Planetary Camera (WF/PC 1) in payload bay during changeout operations. Hoffman is standing on a foot restraint attached to the robot arm of the Remote Manipulator System (RMS) in order to remove the old WF/PC. The new WF/PC has already been installed in cavity (out of frame).

  8. The Status of NASA's Wide-Field Meteor Camera Network and Preliminary Results

    NASA Technical Reports Server (NTRS)

    Blaauw, R.; Cooke, W.; Kingery, A.; Suggs, R.

    2014-01-01

    NASA's Meteoroid Environment Office (MEO) recently established two wide-field cameras to detect meteors in the millimeter-size-range. This paper outlines the concepts of the system, the hardware and software, and results of 3,440 orbits seen from December 13, 2012 until May 14, 2014.

  9. Probing other solar systems with current and future adaptive optics

    SciTech Connect

    Macintosh, B; Marois, C; Phillion, D; Poyneer, L; Graham, J; Zuckerman, B; Gavel, D; Veran, J; Wilhelmsen-Evans, J; Mellis, C

    2008-09-08

    Over the past decade, the study of extrasolar planets through indirect techniques--primarily Doppler measurements--has revolutionized our understanding of other solar systems. The next major step in this field will be the direct detection and characterization, via imaging and spectroscopy, of the planets themselves. To achieve this, we must separate the light from the faint planet from the extensive glare of its parent star. We pursued this goal using the current generation of adaptive optics (AO) systems on large ground-based telescopes, using infrared imaging to search for the thermal emission from young planets and developing image processing techniques to distinguish planets from telescope-induced artifacts. Our new Angular Differential Imaging (ADI) technique, which uses the sidereal rotation of the Earth and telescope, is now standard for ground-based high-contrast imaging. Although no young planets were found in our surveys, we placed the strongest limits yet on giant planets in wide orbits (>30 AU) around young stars and characterized planetary companion candidates. The imaging of planetary companions on solar-system-like scales (5-30 AU) will require a new generation of advanced AO systems that are an order of magnitude more powerful than the LLNL-built Keck AO system. We worked to develop and test the key technologies needed for these systems, including a spatially-filtered wavefront sensor, efficient and accurate wavefront reconstruction algorithms, and precision AO wavefront control at the sub-nm level. LLNL has now been selected by the Gemini Observatory to lead the construction of the Gemini Planet Imager, a $24M instrument that will be the most advanced AO system in the world.

  10. Modulated imaging: A spatial frequency domain imaging method for wide-field spectroscopy and tomography of turbid media

    NASA Astrophysics Data System (ADS)

    Cuccia, David John

    Modulated Imaging (MI) is a fast, scan-free method that enables one to image and quantify the optical properties of turbid media. The technology can simultaneously map surface and sub-surface tissue structure, function and composition. Based on frequency-domain measurement principles, MI uses spatially-periodic or "structured" illumination and camera-based detection to separate and quantify the absorption, scattering, and fluorescence optical properties over a wide field-of-view (many cm) without the need for sample contact. Resolution is depth-dependent and thus scalable (sub-millimeter to millimeter), with depth sensitivity up to a few cm. This method has particularly strong potential for in-vivo clinical and pre-clinical imaging, where optical properties at several wavelengths provide quantitative information on endogeneous chromophore concentrations (i.e. oxy- and deoxy-hemoglobin, fat, and water). These parameters reflect quantitative, localized tissue status such as blood volume, tissue oxygenation, and edema. Using multispectral MI instrumentation, demonstrations of two in-vivo applications are investigated: (1) pre-clinical functional imaging of brain injury in a rodent model and (2) clinical imaging spectroscopy of human skin. Also, preliminary 3D fluorescence tomography data suggest that MI may provide a convenient, low-cost platform for localizing and quantifying exogenous molecular probes in-vivo.

  11. Effects of spatial and spectral frequencies on wide-field functional imaging (wifi) characterization of preclinical breast cancer models

    NASA Astrophysics Data System (ADS)

    Moy, Austin; Kim, Jae G.; Lee, Eva Y. H. P.; Choi, Bernard

    2010-02-01

    A common strategy to study breast cancer is the use of the preclinical model. These models provide a physiologically relevant and controlled environment in which to study both response to novel treatments and the biology of the cancer. Preclinical models, including the spontaneous tumor model and mammary window chamber model, are very amenable to optical imaging and to this end, we have developed a wide-field functional imaging (WiFI) instrument that is perfectly suited to studying tumor metabolism in preclinical models. WiFI combines two optical imaging modalities, spatial frequency domain imaging (SFDI) and laser speckle imaging (LSI). Our current WiFI imaging protocol consists of multispectral imaging in the near infrared (650-980 nm) spectrum, over a wide (7 cm x 5 cm) field of view. Using SFDI, the spatially-resolved reflectance of sinusoidal patterns projected onto the tissue is assessed, and optical properties of the tissue are determined, which are then used to extract tissue chromophore concentrations in the form of oxy-, deoxy-, and total hemoglobin concentrations, and percentage of lipid and water. In the current study, we employ Monte Carlo simulations of SFDI light propagation in order to characterize the penetration depth of light in both the spontaneous tumor model and mammary window chamber model. Preliminary results suggest that different spatial frequency and wavelength combinations have different penetration depths, suggesting the potential depth sectioning capability of the SFDI component of WiFI.

  12. Segmented X-Ray Optics for Future Space Telescopes

    NASA Technical Reports Server (NTRS)

    McClelland, Ryan S.

    2013-01-01

    Lightweight and high resolution mirrors are needed for future space-based X-ray telescopes to achieve advances in high-energy astrophysics. The slumped glass mirror technology in development at NASA GSFC aims to build X-ray mirror modules with an area to mass ratio of approx.17 sq cm/kg at 1 keV and a resolution of 10 arc-sec Half Power Diameter (HPD) or better at an affordable cost. As the technology nears the performance requirements, additional engineering effort is needed to ensure the modules are compatible with space-flight. This paper describes Flight Mirror Assembly (FMA) designs for several X-ray astrophysics missions studied by NASA and defines generic driving requirements and subsequent verification tests necessary to advance technology readiness for mission implementation. The requirement to perform X-ray testing in a horizontal beam, based on the orientation of existing facilities, is particularly burdensome on the mirror technology, necessitating mechanical over-constraint of the mirror segments and stiffening of the modules in order to prevent self-weight deformation errors from dominating the measured performance. This requirement, in turn, drives the mass and complexity of the system while limiting the testable angular resolution. Design options for a vertical X-ray test facility alleviating these issues are explored. An alternate mirror and module design using kinematic constraint of the mirror segments, enabled by a vertical test facility, is proposed. The kinematic mounting concept has significant advantages including potential for higher angular resolution, simplified mirror integration, and relaxed thermal requirements. However, it presents new challenges including low vibration modes and imperfections in kinematic constraint. Implementation concepts overcoming these challenges are described along with preliminary test and analysis results demonstrating the feasibility of kinematically mounting slumped glass mirror segments.

  13. Applications of lobster eye optics

    NASA Astrophysics Data System (ADS)

    Hudec, R.; Pina, L.; Inneman, A.; Tichy, V.

    2015-05-01

    Applications of wide field Lobster Eye X ray telescopes are presented and discussed. The wide field X ray optics was originally proposed for use in X-ray astronomy, but there are numerous other application areas as well.

  14. Current concepts and future perspectives on surgical optical imaging in cancer

    NASA Astrophysics Data System (ADS)

    Ntziachristos, Vasilis; Yoo, Jung Sun; van Dam, Gooitzen M.

    2010-11-01

    There are vibrant developments of optical imaging systems and contrast-enhancing methods that are geared to enhancing surgical vision and the outcome of surgical procedures. Such optical technologies designed for intraoperative use can offer high integration in the operating room compared to conventional radiological modalities adapted to intraoperative applications. Simple fluorescence epi-illumination imaging, in particular, appears attractive but may lead to inaccurate observations due to the complex nature of photon-tissue interaction. Of importance therefore are emerging methods that account for the background optical property variation in tissues and can offer accurate, quantitative imaging that eliminates the appearance of false negatives or positives. In parallel, other nonfluorescent optical imaging methods are summarized and overall progress in surgical optical imaging applications is outlined. Key future directions that have the potential to shift the paradigm of surgical health care are also discussed.

  15. Recent experiments conducted with the Wide-field imaging interferometry testbed (WIIT)

    NASA Astrophysics Data System (ADS)

    Leisawitz, David T.; Juanola-Parramon, Roser; Bolcar, Matthew; Fienup, James R.; Iacchetta, Alexander S.; Maher, Stephen F.; Rinehart, Stephen A.

    2016-08-01

    The Wide-field Imaging Interferometry Testbed (WIIT) was developed at NASA's Goddard Space Flight Center to demonstrate and explore the practical limitations inherent in wide field-of-view "double Fourier" (spatio-spectral) interferometry. The testbed delivers high-quality interferometric data and is capable of observing spatially and spectrally complex hyperspectral test scenes. Although WIIT operates at visible wavelengths, by design the data are representative of those from a space-based far-infrared observatory. We used WIIT to observe a calibrated, independently characterized test scene of modest spatial and spectral complexity, and an astronomically realistic test scene of much greater spatial and spectral complexity. This paper describes the experimental setup, summarizes the performance of the testbed, and presents representative data.

  16. Wide Field-of-View Soft X-Ray Imaging for Solar Wind-Magnetosphere Interactions

    NASA Technical Reports Server (NTRS)

    Walsh, B. M.; Collier, M. R.; Kuntz, K. D.; Porter, F. S.; Sibeck, D. G.; Snowden, S. L.; Carter, J. A.; Collado-Vega, Y.; Connor, H. K.; Cravens, T. E.; Read, A. M.; Sembay, S.; Thomas, N. E.

    2016-01-01

    Soft X-ray imagers can be used to study the mesoscale and macroscale density structures that occur whenever and wherever the solar wind encounters neutral atoms at comets, the Moon, and both magnetized and unmagnetized planets. Charge exchange between high charge state solar wind ions and exospheric neutrals results in the isotropic emission of soft X-ray photons with energies from 0.1 to 2.0 keV. At Earth, this process occurs primarily within the magnetosheath and cusps. Through providing a global view, wide field-of-view imaging can determine the significance of the various proposed solar wind-magnetosphere interaction mechanisms by evaluating their global extent and occurrence patterns. A summary of wide field-of-view (several to tens of degrees) soft X-ray imaging is provided including slumped micropore microchannel reflectors, simulated images, and recent flight results.

  17. Improved sensitivity to fluorescence for cancer detection in wide-field image-guided neurosurgery

    PubMed Central

    Jermyn, Michael; Gosselin, Yoann; Valdes, Pablo A.; Sibai, Mira; Kolste, Kolbein; Mercier, Jeanne; Angulo, Leticia; Roberts, David W.; Paulsen, Keith D.; Petrecca, Kevin; Daigle, Olivier; Wilson, Brian C.; Leblond, Frederic

    2015-01-01

    In glioma surgery, Protoporphyrin IX (PpIX) fluorescence may identify residual tumor that could be resected while minimizing damage to normal brain. We demonstrate that improved sensitivity for wide-field spectroscopic fluorescence imaging is achieved with minimal disruption to the neurosurgical workflow using an electron-multiplying charge-coupled device (EMCCD) relative to a state-of-the-art CMOS system. In phantom experiments the EMCCD system can detect at least two orders-of-magnitude lower PpIX. Ex vivo tissue imaging on a rat glioma model demonstrates improved fluorescence contrast compared with neurosurgical fluorescence microscope technology, and the fluorescence detection is confirmed with measurements from a clinically-validated spectroscopic probe. Greater PpIX sensitivity in wide-field fluorescence imaging may improve the residual tumor detection during surgery with consequent impact on survival. PMID:26713218

  18. Wide-field corrector for 4MOST: design details and MAIV processes

    NASA Astrophysics Data System (ADS)

    Azais, Nicolas; Barden, Samuel C.; Smith, Greg; Jones, Damien; Delabre, Bernard; Egron, Sylvain

    2016-08-01

    The 4-meter Multi-Object Spectroscopic Telescope (4MOST) is a wide-field, high-multiplex spectroscopic survey facility under development for the Visible and Infrared Survey Telescope for Astronomy (VISTA) of the European Southern Observatory (ESO). The primary and secondary mirrors (M1 and M2) together with the Wide Field Corrector (WFC) system provide a pupil-centric and aberration corrected focal surface. The WFC is also an integral part of the metrology system. At the focal surface, we meet two wave front sensing (WFS) systems, a deployable camera at commissioning, an acquisition and guiding (A and G) unit and a secondary guiding unit. This paper provides an overview of design details and Manufacture, Assembly, Integration and Verification (MAIV) processes for the 4MOST WFC system.

  19. Differential speckle and wide-field imaging for the Gemini-North and WIYN telescopes

    NASA Astrophysics Data System (ADS)

    Scott, Nicholas J.; Howell, Steve B.; Horch, Elliott P.

    2016-07-01

    Two new instruments are currently being built for the Gemini-North and WIYN telescopes. They are based on the existing DSSI (Differential Speckle Survey Instrument), but the new dual-channel instruments will have both speckle and "wide-field" imaging capabilities. Nearly identical copies of the instrument will be installed as a public access permanent loan at the Gemini-N and WIYN telescopes. Many exoplanet targets will come from the NASA K2 and TESS missions. The faint limiting magnitude, for speckle observations, will remain around 16 to 17th magnitude depending on observing conditions, while wide-field, high speed imaging should be able to go to 21+. For Gemini, the instrument will be remotely operable from either the mid-level facility at Hale Pohaku or the remote operations base in Hilo.

  20. Improved sensitivity to fluorescence for cancer detection in wide-field image-guided neurosurgery.

    PubMed

    Jermyn, Michael; Gosselin, Yoann; Valdes, Pablo A; Sibai, Mira; Kolste, Kolbein; Mercier, Jeanne; Angulo, Leticia; Roberts, David W; Paulsen, Keith D; Petrecca, Kevin; Daigle, Olivier; Wilson, Brian C; Leblond, Frederic

    2015-12-01

    In glioma surgery, Protoporphyrin IX (PpIX) fluorescence may identify residual tumor that could be resected while minimizing damage to normal brain. We demonstrate that improved sensitivity for wide-field spectroscopic fluorescence imaging is achieved with minimal disruption to the neurosurgical workflow using an electron-multiplying charge-coupled device (EMCCD) relative to a state-of-the-art CMOS system. In phantom experiments the EMCCD system can detect at least two orders-of-magnitude lower PpIX. Ex vivo tissue imaging on a rat glioma model demonstrates improved fluorescence contrast compared with neurosurgical fluorescence microscope technology, and the fluorescence detection is confirmed with measurements from a clinically-validated spectroscopic probe. Greater PpIX sensitivity in wide-field fluorescence imaging may improve the residual tumor detection during surgery with consequent impact on survival.

  1. Wide Field Infra-Red Survey Telescope (WFIRST) 2.4-Meter Mission Study

    NASA Technical Reports Server (NTRS)

    Content, D.; Aaron, K.; Alplanalp, L.; Anderson, K.; Capps, R.; Chang, Z.; Dooley, J.; Egerman, R.; Goullioud, R.; Klein, D.; Kruk, J.; Kuan, G.; Melton, M.; Ruffa, J.; Underhill, M.; Buren, D. Van

    2013-01-01

    The most recent study of the Wide Field Infrared Survey Telescope (WFIRST) mission is based on reuse of an existing 2.4m telescope. This study was commissioned by NASA to examine the potential science return and cost effectiveness of WFIRST by using this significantly larger aperture telescope. We review the science program envisioned by the WFIRST 2012-2013 Science Definition Team (SDT), an overview of the mission concept, and the telescope design and status. Comparisons against the previous 1.3m and reduced cost 1.1m WFIRST design concepts are discussed. A significant departure from past point designs is the option for serviceability and the geostationary orbit location which enables servicing and replacement instrument insertion later during mission life. Other papers at this conference provide more in depth discussion of the wide field instrument and the optional exoplanet imaging coronagraph instrument.

  2. Frequency modulation technique for wide-field imaging of magnetic field with nitrogen-vacancy ensembles

    NASA Astrophysics Data System (ADS)

    Miura, Yukihiro; Kashiwaya, Satoshi; Nomura, Shintaro

    2017-04-01

    We report on the application of a frequency modulation technique to wide-field magnetic field imaging of nitrogen-vacancy centers in diamond at room temperature. We use a scientific CMOS (sCMOS) camera to collect photoluminescence images from a large number of nitrogen-vacancy center ensembles in parallel. This technique allows a significant reduction in the measurement time required to obtain a magnetic field image compared with a scanning probe approach at a comparable magnetic field sensitivity.

  3. Hubble Space Telescope: Wide field and planetary camera instrument handbook. Version 2.1

    NASA Technical Reports Server (NTRS)

    Griffiths, Richard (Editor)

    1990-01-01

    An overview is presented of the development and construction of the Wide Field and Planetary Camera (WF/PC). The WF/PC is a duel two dimensional spectrophotometer with rudimentary polarimetric and transmission grating capabilities. The instrument operates from 1150 to 11000 A with a resolution of 0.1 arcsec per pixel or 0.043 arcsec per pixel. Data products and standard calibration methods are briefly summarized.

  4. A Method for Measuring Distortion in Wide-Field Imaging with High Order Polynomials

    NASA Astrophysics Data System (ADS)

    Yasuda, N.; Okura, Y.; Takata, T.; Furusawa, H.

    2011-07-01

    In analyzing wide-field images, for example those from the Hyper Suprime-Cam on the Subaru telescope, determining World Coordinate System (WCS) information (for example position and angle) of each CCD is very important. In this paper, we show a method for determining the distortion with high-order polynomials using the TAN-SIP convention, utilizing all of the CCDs in a field of view (FOV) at once.

  5. Wide Field Infrared Survey Telescope [WFIRST]: Telescope Design and Simulated Performance

    NASA Technical Reports Server (NTRS)

    Goullioud, R.; Content, D. A.; Kuan, G. M.; Moore, J. D.; Chang, Z.; Sunada, E. T.; Villalvazo, J.; Hawk, J. P.; Armani, N. V.; Johnson, E. L.; Powell, C. A.

    2012-01-01

    The ASTRO2010 Decadal Survey proposed multiple missions with NIR focal planes and 3 mirror wide field telescopes in the 1.5m aperture range. None of them would have won as standalone missions WFIRST is a combination of these missions, created by Astro 2010 committee. WFIRST Science Definition Team (SDT) tasked to examine the design. Project team is a GSFC-JPL-Caltech collaboration. This interim mission design is a result of combined work by the project team with the SDT.

  6. An EUV Wide-Field Imager and Spectrometer for the ISS

    NASA Technical Reports Server (NTRS)

    Golub, Leon; Savage, Sabrina

    2016-01-01

    The Coronal Spectrographic Imager in the EUV, COSIE, combines a wide-field solar coronal EUV imager (EUVC) and an on-disk EUV imaging spectrometer (EUVS). Located on the International Space Station (ISS), the goal of the mission is to enhance our understanding of the dynamics of the Transition Corona (the region in which the coronal magnetic field transitions from closed to open), and to provide improved detection and tracking of solar eruptive events for space weather research.

  7. Wide-field four-channel fluorescence imager for biological applications

    NASA Astrophysics Data System (ADS)

    Thakur, Madhuri; Melnik, Dmitry; Barnett, Heather; Daly, Kevin; Moran, Christine H.; Chang, Wei-Shun; Link, Stephan; Bucher, Christopher Theodore; Kittrell, Carter; Curl, Robert

    2010-03-01

    A wide-field four-channel fluorescence imager has been developed. The instrument uses four expanded laser beams to image a large section (6 mm×9 mm). An object can be sequentially illuminated with any combination of 408-, 532-, 658-, and 784-nm lasers for arbitrary (down to 1 ms) exposure times for each laser. Just two notch filters block scattered light from all four lasers. The design approach described here offers great flexibility in treatment of objects, very good sensitivity, and a wide field of view at low cost. There appears to be no commercial instrument capable of simultaneous fluorescence imaging of a wide field of view with four-laser excitation. Some possible applications are following events such as flow and mixing in microchannel systems, the transmission of biological signals across a culture, and following simulations of biological membrane diffusion. It can also be used in DNA sequencing by synthesis to follow the progress of the photolytic removal of dye and terminator. Without utilizing its time resolution, it can be used to obtain four independent images of a single tissue section stained with four targeting agents, with each coupled to a different dye matching one of the lasers.

  8. Intra-familial Similarity of Wide-Field Fundus Autofluorescence in Inherited Retinal Dystrophy.

    PubMed

    Furutani, Yuka; Ogino, Ken; Oishi, Akio; Gotoh, Norimoto; Makiyama, Yukiko; Oishi, Maho; Kurimoto, Masafumi; Yoshimura, Nagahisa

    2016-01-01

    To examine the similarity of wide-field fundus autofluorescence (FAF) imaging in inherited retinal dystrophy between siblings and between parents and their children. The subjects included 17 siblings (12 with retinitis pigmentosa and 5 with cone rod dystrophy) and 10 parent-child pairs (8 with retinitis pigmentosa and 2 with cone rod dystrophy). We quantified the similarity of wide-field FAF using image processing techniques of cropping, binarization, superimposition, and subtraction. The estimated similarity of the siblings was compared with that of the parent-child pairs and that of the age-matched unrelated patients. The similarity between siblings was significantly higher that of parent-child pairs or that of age-matched unrelated patients (P = 0.004 and P = 0.049, respectively). Wide-field FAF images were similar between siblings with inherited retinal dystrophy but different between parent-child pairs. This suggests that aging is a confounding factor in genotype-phenotype correlation studies.

  9. Wide Field Of View Varifocal Near-Eye Display Using See-Through Deformable Membrane Mirrors.

    PubMed

    Dunn, David; Tippets, Cary; Torell, Kent; Kellnhofer, Petr; Aksit, Kaan; Didyk, Piotr; Myszkowski, Karol; Luebke, David; Fuchs, Henry

    2017-04-01

    Accommodative depth cues, a wide field of view, and ever-higher resolutions all present major hardware design challenges for near-eye displays. Optimizing a design to overcome one of these challenges typically leads to a trade-off in the others. We tackle this problem by introducing an all-in-one solution - a new wide field of view, gaze-tracked near-eye display for augmented reality applications. The key component of our solution is the use of a single see-through, varifocal deformable membrane mirror for each eye reflecting a display. They are controlled by airtight cavities and change the effective focal power to present a virtual image at a target depth plane which is determined by the gaze tracker. The benefits of using the membranes include wide field of view (100° diagonal) and fast depth switching (from 20 cm to infinity within 300 ms). Our subjective experiment verifies the prototype and demonstrates its potential benefits for near-eye see-through displays.

  10. CHIMERA: a wide-field, multi-colour, high-speed photometer at the prime focus of the Hale telescope

    NASA Astrophysics Data System (ADS)

    Harding, L. K.; Hallinan, G.; Milburn, J.; Gardner, P.; Konidaris, N.; Singh, N.; Shao, M.; Sandhu, J.; Kyne, G.; Schlichting, H. E.

    2016-04-01

    The Caltech HIgh-speed Multi-colour camERA (CHIMERA) is a new instrument that has been developed for use at the prime focus of the Hale 200-inch telescope. Simultaneous optical imaging in two bands is enabled by a dichroic beam splitter centred at 567 nm, with Sloan u' and g' bands available on the blue arm and Sloan r', i' and z_s bands available on the red arm. Additional narrow-band filters will also become available as required. An electron multiplying CCD (EMCCD) detector is employed for both optical channels, each capable of simultaneously delivering sub-electron effective read noise under multiplication gain and frame rates of up to 26 fps full frame (several 1000 fps windowed), over a fully corrected 5 × 5 arcmin field of view. CHIMERA was primarily developed to enable the characterization of the size distribution of sub-km Kuiper Belt Objects via stellar occultation, a science case that motivates the frame-rate, the simultaneous multi-colour imaging and the wide field of view of the instrument. In addition, it also has unique capability in the detection of faint near-Earth asteroids and will be used for the monitoring of short-duration transient and periodic sources, particularly those discovered by the intermediate Palomar Transient Factory (iPTF), and the upcoming Zwicky Transient Facility (ZTF).

  11. An integrative approach for analyzing hundreds of neurons in task performing mice using wide-field calcium imaging

    PubMed Central

    Mohammed, Ali I.; Gritton, Howard J.; Tseng, Hua-an; Bucklin, Mark E.; Yao, Zhaojie; Han, Xue

    2016-01-01

    Advances in neurotechnology have been integral to the investigation of neural circuit function in systems neuroscience. Recent improvements in high performance fluorescent sensors and scientific CMOS cameras enables optical imaging of neural networks at a much larger scale. While exciting technical advances demonstrate the potential of this technique, further improvement in data acquisition and analysis, especially those that allow effective processing of increasingly larger datasets, would greatly promote the application of optical imaging in systems neuroscience. Here we demonstrate the ability of wide-field imaging to capture the concurrent dynamic activity from hundreds to thousands of neurons over millimeters of brain tissue in behaving mice. This system allows the visualization of morphological details at a higher spatial resolution than has been previously achieved using similar functional imaging modalities. To analyze the expansive data sets, we developed software to facilitate rapid downstream data processing. Using this system, we show that a large fraction of anatomically distinct hippocampal neurons respond to discrete environmental stimuli associated with classical conditioning, and that the observed temporal dynamics of transient calcium signals are sufficient for exploring certain spatiotemporal features of large neural networks. PMID:26854041

  12. Wide-field imaging of birefringent synovial fluid crystals using lens-free polarized microscopy for gout diagnosis

    PubMed Central

    Zhang, Yibo; Lee, Seung Yoon Celine; Zhang, Yun; Furst, Daniel; Fitzgerald, John; Ozcan, Aydogan

    2016-01-01

    Gout is a form of crystal arthropathy where monosodium urate (MSU) crystals deposit and elicit inflammation in a joint. Diagnosis of gout relies on identification of MSU crystals under a compensated polarized light microscope (CPLM) in synovial fluid aspirated from the patient’s joint. The detection of MSU crystals by optical microscopy is enhanced by their birefringent properties. However, CPLM partially suffers from the high-cost and bulkiness of conventional lens-based microscopy, and its relatively small field-of-view (FOV) limits the efficiency and accuracy of gout diagnosis. Here we present a lens-free polarized microscope which adopts a novel differential and angle-mismatched polarizing optical design achieving wide-field and high-resolution holographic imaging of birefringent objects with a color contrast similar to that of a standard CPLM. The performance of this computational polarization microscope is validated by imaging MSU crystals made from a gout patient’s tophus and steroid crystals used as negative control. This lens-free polarized microscope, with its wide FOV (>20 mm2), cost-effectiveness and field-portability, can significantly improve the efficiency and accuracy of gout diagnosis, reduce costs, and can be deployed even at the point-of-care and in resource-limited clinical settings. PMID:27356625

  13. An integrative approach for analyzing hundreds of neurons in task performing mice using wide-field calcium imaging.

    PubMed

    Mohammed, Ali I; Gritton, Howard J; Tseng, Hua-an; Bucklin, Mark E; Yao, Zhaojie; Han, Xue

    2016-02-08

    Advances in neurotechnology have been integral to the investigation of neural circuit function in systems neuroscience. Recent improvements in high performance fluorescent sensors and scientific CMOS cameras enables optical imaging of neural networks at a much larger scale. While exciting technical advances demonstrate the potential of this technique, further improvement in data acquisition and analysis, especially those that allow effective processing of increasingly larger datasets, would greatly promote the application of optical imaging in systems neuroscience. Here we demonstrate the ability of wide-field imaging to capture the concurrent dynamic activity from hundreds to thousands of neurons over millimeters of brain tissue in behaving mice. This system allows the visualization of morphological details at a higher spatial resolution than has been previously achieved using similar functional imaging modalities. To analyze the expansive data sets, we developed software to facilitate rapid downstream data processing. Using this system, we show that a large fraction of anatomically distinct hippocampal neurons respond to discrete environmental stimuli associated with classical conditioning, and that the observed temporal dynamics of transient calcium signals are sufficient for exploring certain spatiotemporal features of large neural networks.

  14. Three-dimensional imaging and image analysis of hippocampal neurons: confocal and digitally enhanced wide field microscopy.

    PubMed

    Turner, J N; Szarowski, D H; Turner, T J; Ancin, H; Lin, W C; Roysam, B; Holmes, T J

    1994-11-01

    The microscopy of biological specimens has traditionally been a two-dimensional imaging method for analyzing what are in reality three-dimensional (3-D) objects. This has been a major limitation of the application of one of science's most widely used tools. Nowhere has this limitation been more acute than in neurobiology, which is dominated by the necessity of understanding both large- and small-scale 3-D anatomy. Fortunately, recent advances in optical instrumentation and computational methods have provided the means for retrieving the third dimension, making full 3-D microscopic imaging possible. Optical designs have concentrated on the confocal imaging mode while computational methods have made 3-D imaging possible with wide field microscopes using deconvolution methods. This work presents a brief review of these methods, especially as applied to neurobiology, and data using both approaches. Specimens several hundred micrometers thick can be sampled allowing essentially intact neurons to be imaged. These neurons or selected components can be contrasted with either fluorescent, absorption, or reflection stains. Image analysis in 3-D is as important as visualization in 3-D. Automated methods of cell counting and analysis by nuclear detection as well as tracing of individual neurons are presented.

  15. Wide-field imaging of birefringent synovial fluid crystals using lens-free polarized microscopy for gout diagnosis

    NASA Astrophysics Data System (ADS)

    Zhang, Yibo; Lee, Seung Yoon Celine; Zhang, Yun; Furst, Daniel; Fitzgerald, John; Ozcan, Aydogan

    2016-06-01

    Gout is a form of crystal arthropathy where monosodium urate (MSU) crystals deposit and elicit inflammation in a joint. Diagnosis of gout relies on identification of MSU crystals under a compensated polarized light microscope (CPLM) in synovial fluid aspirated from the patient’s joint. The detection of MSU crystals by optical microscopy is enhanced by their birefringent properties. However, CPLM partially suffers from the high-cost and bulkiness of conventional lens-based microscopy, and its relatively small field-of-view (FOV) limits the efficiency and accuracy of gout diagnosis. Here we present a lens-free polarized microscope which adopts a novel differential and angle-mismatched polarizing optical design achieving wide-field and high-resolution holographic imaging of birefringent objects with a color contrast similar to that of a standard CPLM. The performance of this computational polarization microscope is validated by imaging MSU crystals made from a gout patient’s tophus and steroid crystals used as negative control. This lens-free polarized microscope, with its wide FOV (>20 mm2), cost-effectiveness and field-portability, can significantly improve the efficiency and accuracy of gout diagnosis, reduce costs, and can be deployed even at the point-of-care and in resource-limited clinical settings.

  16. THE HUBBLE WIDE FIELD CAMERA 3 TEST OF SURFACES IN THE OUTER SOLAR SYSTEM: SPECTRAL VARIATION ON KUIPER BELT OBJECTS

    SciTech Connect

    Fraser, Wesley C.; Brown, Michael E.; Glass, Florian

    2015-05-01

    Here, we present additional photometry of targets observed as part of the Hubble Wide Field Camera 3 (WFC3) Test of Surfaces in the Outer Solar System. Twelve targets were re-observed with the WFC3 in the optical and NIR wavebands designed to complement those used during the first visit. Additionally, all of the observations originally presented by Fraser and Brown were reanalyzed through the same updated photometry pipeline. A re-analysis of the optical and NIR color distribution reveals a bifurcated optical color distribution and only two identifiable spectral classes, each of which occupies a broad range of colors and has correlated optical and NIR colors, in agreement with our previous findings. We report the detection of significant spectral variations on five targets which cannot be attributed to photometry errors, cosmic rays, point-spread function or sensitivity variations, or other image artifacts capable of explaining the magnitude of the variation. The spectrally variable objects are found to have a broad range of dynamical classes and absolute magnitudes, exhibit a broad range of apparent magnitude variations, and are found in both compositional classes. The spectrally variable objects with sufficiently accurate colors for spectral classification maintain their membership, belonging to the same class at both epochs. 2005 TV189 exhibits a sufficiently broad difference in color at the two epochs that span the full range of colors of the neutral class. This strongly argues that the neutral class is one single class with a broad range of colors, rather than the combination of multiple overlapping classes.

  17. A Spitzer Far-infrared Look at the NOAO-Deep Wide Field Survey

    NASA Astrophysics Data System (ADS)

    Le Floc'h, Emeric

    2006-12-01

    The NDFWS was imaged and spectroscopically followed-up in the midand far-IR (5-35mic, 70mic, 160mic) with the MIPS and IRS instruments on-board the Spitzer Space Telescope. I will discuss the main results that have been obtained so far from the combination of these observations with other wavelength data (X-ray, optical, radio) available across the field. This includes the IR characterization of the spectral energy distribution of IR/radio/Ly-alpha selected starburst galaxies and AGNs at high redshift, the study of AGN/starburst diagnostics based on mid-IR properties, the redshift distribution of mid-IR selected sources and the mid-IR luminosity function of quasars up to z 5. In particular, I will also emphasize the discovery of a population of 2optically-faint and dust-enshrouded sources with extremely high mid-IR luminosities mostly powered by accretion of material around AGNs. I will describe the properties of this population and discuss its potential role in the context of a coeval growth of bulges and super massive black holes. Other aspects of these sources to be explored in the near future will be briefly mentioned.

  18. A PANCHROMATIC CATALOG OF EARLY-TYPE GALAXIES AT INTERMEDIATE REDSHIFT IN THE HUBBLE SPACE TELESCOPE WIDE FIELD CAMERA 3 EARLY RELEASE SCIENCE FIELD

    SciTech Connect

    Rutkowski, M. J.; Cohen, S. H.; Windhorst, R. A.; Kaviraj, S.; Crockett, R. M.; Silk, J.; O'Connell, R. W.; Hathi, N. P.; McCarthy, P. J.; Ryan, R. E. Jr.; Koekemoer, A.; Bond, H. E.; Yan, H.; Kimble, R. A.; Balick, B.; Calzetti, D.; Disney, M. J.; Dopita, M. A.; Frogel, J. A.; Hall, D. N. B.; and others

    2012-03-01

    In the first of a series of forthcoming publications, we present a panchromatic catalog of 102 visually selected early-type galaxies (ETGs) from observations in the Early Release Science (ERS) program with the Wide Field Camera 3 (WFC3) on the Hubble Space Telescope (HST) of the Great Observatories Origins Deep Survey-South (GOODS-S) field. Our ETGs span a large redshift range, 0.35 {approx}< z {approx}< 1.5, with each redshift spectroscopically confirmed by previous published surveys of the ERS field. We combine our measured WFC3 ERS and Advanced Camera for Surveys (ACS) GOODS-S photometry to gain continuous sensitivity from the rest-frame far-UV to near-IR emission for each ETG. The superior spatial resolution of the HST over this panchromatic baseline allows us to classify the ETGs by their small-scale internal structures, as well as their local environment. By fitting stellar population spectral templates to the broadband photometry of the ETGs, we determine that the average masses of the ETGs are comparable to the characteristic stellar mass of massive galaxies, 10{sup 11} < M{sub *}[M{sub Sun }]<10{sup 12}. By transforming the observed photometry into the Galaxy Evolution Explorer FUV and NUV, Johnson V, and Sloan Digital Sky Survey g' and r' bandpasses we identify a noteworthy diversity in the rest-frame UV-optical colors and find the mean rest-frame (FUV-V) = 3.5 and (NUV-V) = 3.3, with 1{sigma} standard deviations {approx_equal}1.0. The blue rest-frame UV-optical colors observed for most of the ETGs are evidence for star formation during the preceding gigayear, but no systems exhibit UV-optical photometry consistent with major recent ({approx}<50 Myr) starbursts. Future publications which address the diversity of stellar populations likely to be present in these ETGs, and the potential mechanisms by which recent star formation episodes are activated, are discussed.

  19. A Review of Adaptive Optics Optical Coherence Tomography: Technical Advances, Scientific Applications, and the Future

    PubMed Central

    Jonnal, Ravi S.; Kocaoglu, Omer P.; Zawadzki, Robert J.; Liu, Zhuolin; Miller, Donald T.; Werner, John S.

    2016-01-01

    Purpose Optical coherence tomography (OCT) has enabled “virtual biopsy” of the living human retina, revolutionizing both basic retina research and clinical practice over the past 25 years. For most of those years, in parallel, adaptive optics (AO) has been used to improve the transverse resolution of ophthalmoscopes to foster in vivo study of the retina at the microscopic level. Here, we review work done over the last 15 years to combine the microscopic transverse resolution of AO with the microscopic axial resolution of OCT, building AO-OCT systems with the highest three-dimensional resolution of any existing retinal imaging modality. Methods We surveyed the literature to identify the most influential antecedent work, important milestones in the development of AO-OCT technology, its applications that have yielded new knowledge, research areas into which it may productively expand, and nascent applications that have the potential to grow. Results Initial efforts focused on demonstrating three-dimensional resolution. Since then, many improvements have been made in resolution and speed, as well as other enhancements of acquisition and postprocessing techniques. Progress on these fronts has produced numerous discoveries about the anatomy, function, and optical properties of the retina. Conclusions Adaptive optics OCT continues to evolve technically and to contribute to our basic and clinical knowledge of the retina. Due to its capacity to reveal cellular and microscopic detail invisible to clinical OCT systems, it is an ideal companion to those instruments and has the demonstrable potential to produce images that can guide the interpretation of clinical findings. PMID:27409507

  20. SIMULTANEOUS EXOPLANET CHARACTERIZATION AND DEEP WIDE-FIELD IMAGING WITH A DIFFRACTIVE PUPIL TELESCOPE

    SciTech Connect

    Guyon, Olivier; Eisner, Josh A.; Angel, Roger; Woolf, Neville J.; Bendek, Eduardo A.; Milster, Thomas D.; Ammons, S. Mark; Shao, Michael; Shaklan, Stuart; Levine, Marie; Nemati, Bijan; Martinache, Frantz; Pitman, Joe; Woodruff, Robert A.; Belikov, Ruslan

    2013-04-10

    High-precision astrometry can identify exoplanets and measure their orbits and masses while coronagraphic imaging enables detailed characterization of their physical properties and atmospheric compositions through spectroscopy. In a previous paper, we showed that a diffractive pupil telescope (DPT) in space can enable sub-{mu}as accuracy astrometric measurements from wide-field images by creating faint but sharp diffraction spikes around the bright target star. The DPT allows simultaneous astrometric measurement and coronagraphic imaging, and we discuss and quantify in this paper the scientific benefits of this combination for exoplanet science investigations: identification of exoplanets with increased sensitivity and robustness, and ability to measure planetary masses to high accuracy. We show how using both measurements to identify planets and measure their masses offers greater sensitivity and provides more reliable measurements than possible with separate missions, and therefore results in a large gain in mission efficiency. The combined measurements reliably identify potentially habitable planets in multiple systems with a few observations, while astrometry or imaging alone would require many measurements over a long time baseline. In addition, the combined measurement allows direct determination of stellar masses to percent-level accuracy, using planets as test particles. We also show that the DPT maintains the full sensitivity of the telescope for deep wide-field imaging, and is therefore compatible with simultaneous scientific observations unrelated to exoplanets. We conclude that astrometry, coronagraphy, and deep wide-field imaging can be performed simultaneously on a single telescope without significant negative impact on the performance of any of the three techniques.

  1. Far ultraviolet wide field imaging with a SPARTAN /Experiment of Opportunity/ Payload

    NASA Technical Reports Server (NTRS)

    Carruthers, G. R.; Heckathorn, H. M.; Opal, C. B.

    1982-01-01

    A wide-field electrographic Schmidt camera, sensitive in the far UV (1230-2000 A), has been developed and utilized in three sounding rocket flights. It is now being prepared for Shuttle flight as an Experiment of Opportunity Payload (EOP) (recently renamed as the SPARTAN program). In this paper, we discuss (1) design of the instrument and payload, particularly as influenced by our experience in rocket flights; (2) special problems of EOP in comparison to sounding rocket missions; (3) relationship of this experiment to, and special capabilities in comparison to, other space astronomy instruments such as Space Telescope; and (4) a tentative observing plan for an EOP mission.

  2. Far ultraviolet wide field imaging and photometry - Spartan-202 Mark II Far Ultraviolet Camera

    NASA Technical Reports Server (NTRS)

    Carruthers, George R.; Heckathorn, Harry M.; Opal, Chet B.; Witt, Adolf N.; Henize, Karl G.

    1988-01-01

    The U.S. Naval Research Laboratory' Mark II Far Ultraviolet Camera, which is expected to be a primary scientific instrument aboard the Spartan-202 Space Shuttle mission, is described. This camera is intended to obtain FUV wide-field imagery of stars and extended celestial objects, including diffuse nebulae and nearby galaxies. The observations will support the HST by providing FUV photometry of calibration objects. The Mark II camera is an electrographic Schmidt camera with an aperture of 15 cm, a focal length of 30.5 cm, and sensitivity in the 1230-1600 A wavelength range.

  3. Wide-field compact catadioptric telescope spanning 0.7-14 μm wavelengths.

    PubMed

    Marks, Daniel L; Hagen, Nathan; Durham, Mark; Brady, David J

    2013-06-20

    We present a wide-field compact f-1.2, f-1.6 effective illumination catadioptric telescope that spans the wavelengths 0.7-14.0 μm. Such a telescope replaces several telescopes designed for different infrared bands, while having a track length shorter than most single-band telescopes. Incorporated with a suitable multiband focal plane array, many wavelength bands may be imaged simultaneously in the same instrument. We have constructed and tested prototypes of the telescopes and found the performance is near the predicted values.

  4. Modified Savart polariscope with wide field of view and achromatic lateral displacement

    NASA Astrophysics Data System (ADS)

    Quan, Naicheng; Zhang, Chunmin; Mu, Tingkui

    2017-01-01

    A modified Savart polariscope with wide field of view and achromatic lateral displacement is presented. The modified Savart polariscope can be made from two different birefringent crystal materials. The principle of the element is described and the impacts of systematic errors are analyzed. The achievement and performance of the modified Savart polariscope is demonstrated with numerical simulations. The maximum acceptable angle of incidence can be increased by an order of magnitude and the chromatic variations in lateral displacement are inhibited obviously across the specified spectral range 0.4 μm to 0.9 μm.

  5. The First Hundred Brown Dwarfs Discovered by the Wide-Field Infrared Survey Explorer (WISE)

    NASA Technical Reports Server (NTRS)

    Kirkpatrick, J. Davy; Cushing, Michael C.; Gelino, Christopher R.; Griffith, Roger L.; Skrutskie, Michael F.; Marsh, Kenneth A.; Wright, Edward L.; Mainzer, Amanda K.; Eisenhardt, Peter R.; McLean, Ian S.; Bauer, James M.; Benford, Dominic J.; Lake, Sean E.; Petty, Sara M.; Tsai, Chao-Wei; Beichman, Charles; Stapelfeldt, Karl R.; Stern, Daniel; Vacca, William D.

    2011-01-01

    We present ground-based spectroscopic verification of six Y dwarfs also Cushing et al.), eighty-nine T dwarfs, eight L dwarfs, and one M dwarf identified by the Wide-field Infrared Survey Explorer (WISE). Eighty of these are cold brown dwarfs with spectral types > or =T6, six of which have been announced earlier in Mainzer et al. and I3urgasser et al. We present color-color and colortype diagrams showing the locus of M, L, T, and Y dwarfs in WISE color space. "

  6. On the Design of Wide-Field X-ray Telescopes

    NASA Technical Reports Server (NTRS)

    Elsner, Ronald F.; O'Dell, Stephen L.; Ramsey, Brian D.; Weiskopf, Martin C.

    2009-01-01

    X-ray telescopes having a relatively wide field-of-view and spatial resolution vs. polar off-axis angle curves much flatter than the parabolic dependence characteristic of Wolter I designs are of great interest for surveys of the X-ray sky and potentially for study of the Sun s X-ray emission. We discuss the various considerations affecting the design of such telescopes, including the possible use of polynomial mirror surface prescriptions, a method of optimizing the polynomial coefficients, scaling laws for mirror segment length vs. intersection radius, the loss of on-axis spatial resolution, and the positioning of focal plane detectors.

  7. CPAPIR: a wide-field infrared camera for the Observatoire du Mont Megantic

    NASA Astrophysics Data System (ADS)

    Artigau, Etienne; Doyon, Rene; Vallee, Philippe; Riopel, Martin; Nadeau, Daniel

    2004-09-01

    CPAPIR is a wide-field infrared camera for use at the Observatoire du mont Megantic and CTIO 1.5 m telescopes. The camera will be primarily a survey instrument with a half-degree field of view, making it one of the most efficient of its kind. CPAPIR will provide broad and narrow band filters within its 0.8 to 2.5 μm bandpass. The camera is based on a Hawaii-2 2048x2048 HgCdTe detector.

  8. Micrometeoroid Impacts on the Hubble Space Telescope Wide Field and Planetary Camera 2: Larger Particles

    NASA Technical Reports Server (NTRS)

    Kearsley, A. T.; Grime, G. W.; Webb, R. P.; Jeynes, C.; Palitsin, V.; Colaux, J. L.; Ross, D. K.; Anz-Meador, P.; Liou, J. C.; Opiela, J.; Griffin, G. T.; Gerlach, L.; Wozniakiewicz, P. J.; Price, M. C.; Burchell, M. J.; Cole, M. J.

    2014-01-01

    The Wide Field and Planetary Camera 2 (WFPC2) was returned from the Hubble Space Telescope (HST) by shuttle mission STS-125 in 2009. In space for 16 years, the surface accumulated hundreds of impact features on the zinc orthotitanate paint, some penetrating through into underlying metal. Larger impacts were seen in photographs taken from within the shuttle orbiter during service missions, with spallation of paint in areas reaching 1.6 cm across, exposing alloy beneath. Here we describe larger impact shapes, the analysis of impactor composition, and the micrometeoroid (MM) types responsible.

  9. Cryogenic Optical Performance of a Lightweighted Mirror Assembly for Future Space Astronomical Telescopes: Correlating Optical Test Results and Thermal Optical Model

    NASA Technical Reports Server (NTRS)

    Eng, Ron; Arnold, William R.; Baker, Marcus A.; Bevan, Ryan M.; Burdick, Gregory; Effinger, Michael R.; Gaddy, Darrell E.; Goode, Brian K.; Hanson, Craig; Hogue, William D.; Kegley, Jeffrey R.; Kirk, Charlie; Maffett, Steven P.; Matthews, Gary W.; Siler, Richard D.; Smith, W. Scott; Stahl, H. Philip; Tucker, John M.; Wright, Ernest R.

    2013-01-01

    A 43cm diameter stacked core mirror demonstrator was interferometrically tested at room temperature down to 250 degrees Kelvin for thermal deformation. The 2.5m radius of curvature spherical mirror assembly was constructed by low temperature fusing three abrasive waterjet core sections between two CNC pocket milled face sheets. The 93% lightweighted Corning ULE® mirror assembly represents the current state of the art for future UV, optical, near IR space telescopes. During the multiple thermal test cycles, test results of interferometric test, thermal IR images of the front face were recorded in order to validate thermal optical model.

  10. Cryogenic Optical Performance of a Light-weight Mirror Assembly for Future Space Astronomical Telescopes: Optical Test Results and Thermal Optical Model

    NASA Technical Reports Server (NTRS)

    Eng, Ron; Arnold, William; Baker, Markus A.; Bevan, Ryan M.; Carpenter, James R.; Effinger, Michael R.; Gaddy, Darrell E.; Goode, Brian K.; Kegley, Jeffrey R.; Hogue, William D.; Siler, Richard D.; Smith, W. Scott; Stahl. H. Philip; Tucker, John M.; Wright, Ernest R.; Kirk, Charles S.; Hanson, Craig; Burdick, Gregory; Maffett, Steven

    2013-01-01

    A 40 cm diameter mirror assembly was interferometrically tested at room temperature down to 250 degrees Kelvin for thermal deformation. The 2.5 m radius of curvature spherical mirror assembly was constructed by low temperature fusing three abrasive waterjet core sections between two face sheets. The 93% lightweighted Corning ULE mirror assembly represents the current state of the art for future UV, optical, near IR space telescopes. During the multiple thermal test cycles, test results of interferometric test, thermal IR images of the front face were recorded in order to validate thermal optical model.

  11. Improved wide-field collimator for dynamic testing of the GOES imager and sounder

    NASA Astrophysics Data System (ADS)

    Bremer, James C.; Etemad, Shahriar; Zukowski, Barbara J.; Pasquale, Bert A.; Zukowski, Tmitri J.; Prince, Robert E.; Holmes, Vincent; Ryskewich, John A.; O'Neill, Patrick; Murphy-Morris, Jeanine E.

    2002-09-01

    The GOES Imager and Sounder instruments each observe the full Earth disk, 17.4° in diameter, from geostationary orbit. Pre-launch, each instrument's dynamic scanning performance is tested using the projection of a test pattern from a wide-field collimator. We are fabricating a second wide-field collimator (WFC2) to augment this test program. The WFC2 has several significant advantages over the existing WFC1. The WFC2 target illumination system uses an array of light-emitting diodes (LEDs) radiating at 680nm, which is within the visible bands of both the Imager and Sounder. The light from the LEDs is projected through a non-Lambertian diffuser plate and the target plate to the pupil of the projection lens. The WFC2's power dissipation is much lower than that of WFC1, decreasing stabilization time and eliminating the need for cooling fans. The WFC2's custom-designed 5-element projection lens has the same effective focal length (EFL) as the WFC1 projection lens. The WFC2 lens is optimized for the LED's narrow spectral band simplifying the design and improving image quality. The target plate is mounted in a frame with a mechanized micro-positioner system that controls three degrees of freedom: tip, tilt, and focus. The tip and tilt axes intersect in the WFC's image plane, and all adjustments are controlled remotely by the operator observing the target plate through an auto-collimating telescope.

  12. Fluorescent Nanowire Ring Illumination for Wide-Field Far-Field Subdiffraction Imaging

    NASA Astrophysics Data System (ADS)

    Liu, Xiaowei; Kuang, Cuifang; Hao, Xiang; Pang, Chenlei; Xu, Pengfei; Li, Haifeng; Liu, Ying; Yu, Chao; Xu, Yingke; Nan, Di; Shen, Weidong; Fang, Yue; He, Lenian; Liu, Xu; Yang, Qing

    2017-02-01

    Here we demonstrate an active method which pioneers in utilizing a combination of a spatial frequency shift and a Stokes frequency shift to enable wide-field far-field subdiffraction imaging. A fluorescent nanowire ring acts as a localized source and is combined with a film waveguide to produce omnidirectional illuminating evanescent waves. Benefitting from the high wave vector of illumination, the high spatial frequencies of an object can be shifted to the passband of a conventional imaging system, contributing subwavelength spatial information to the far-field image. A structure featuring 70-nm-wide slots spaced 70 nm apart has been resolved at a wavelength of 520 nm with a 0.85 numerical aperture standard objective based on this method. The versatility of this approach has been demonstrated by imaging integrated chips, Blu-ray DVDs, biological cells, and various subwavelength 2D patterns, with a viewing area of up to 1 0 0 0 μ m2 , which is one order of magnitude larger than the previous far-field and full-field nanoscopy methods. This new resolving technique is label-free, is conveniently integrated with conventional microscopes, and can potentially become an important tool in cellular biology, the on-chip industry, as well as other fields requiring wide-field nanoscale visualization.

  13. Generalized mesh-based Monte Carlo for wide-field illumination and detection via mesh retessellation

    PubMed Central

    Yao, Ruoyang; Intes, Xavier; Fang, Qianqian

    2015-01-01

    Monte Carlo methods are commonly used as the gold standard in modeling photon transport through turbid media. With the rapid development of structured light applications, an accurate and efficient method capable of simulating arbitrary illumination patterns and complex detection schemes over large surface area is in great need. Here we report a generalized mesh-based Monte Carlo algorithm to support a variety of wide-field illumination methods, including spatial-frequency-domain imaging (SFDI) patterns and arbitrary 2-D patterns. The extended algorithm can also model wide-field detectors such as a free-space CCD camera. The significantly enhanced flexibility of source and detector modeling is achieved via a fast mesh retessellation process that combines the target domain and the source/detector space in a single tetrahedral mesh. Both simulations of complex domains and comparisons with phantom measurements are included to demonstrate the flexibility, efficiency and accuracy of the extended algorithm. Our updated open-source software is provided at http://mcx.space/mmc. PMID:26819826

  14. Wide field nulling imager for TPF: the Boeing-SVS hypertelescope concept

    NASA Astrophysics Data System (ADS)

    Guyon, Olivier

    2003-02-01

    The Terrestrial Planet Finder (TPF) mission is aimed at providing direct images of Earth-like planets orbiting nearby stars and characterizing their atmospheres (low resolution spectroscopy). The BOEING/SVS hypertelescope concept, NRLA (Non-Redundant Linear Array), uses a 35m baseline interferometric rotating array of six 2.3-meter telescopes operating in the infrared (7 to 12 microns) to produce wide field images of exoplanetary systems. The full (u,v) plane coverage of the array offers very good imaging capabilities, which is essential to unambiguously confirm the detection of planets, and also provides an outstanding capability for high resolution/high dynamic range imaging for general astrophysics. Thanks to a novel approach combining pupil densification, phase mask coronagraphy and pupil redilution, this concept combines wide field of view imaging and interferometric nulling of the central star. We first briefly present the techniques used by this concept (phase mask coronagraphy, pupil densification and redilution, aperture synthesis imaging) and demonstrate how they can be used to overcome the limitations commonly encountered by interferometers (low (u,v) plane coverage, small field of view, low dynamical range). A complete computer simulation of the concept has been written and is used to study the performance of the array for exoplanet imaging and spectroscopy. We show that with this concept, detection (S/N=5) of Earth-like planets at 10pc with a 5 microns spectral bandwidth can be achieved in less than an hour (for a 100% quantum efficiency).

  15. HUBBLE SPACE TELESCOPE SPECTROSCOPY OF BROWN DWARFS DISCOVERED WITH THE WIDE-FIELD INFRARED SURVEY EXPLORER

    SciTech Connect

    Schneider, Adam C.; Cushing, Michael C.; Kirkpatrick, J. Davy; Gelino, Christopher R.; Mace, Gregory N.; Wright, Edward L.; Eisenhardt, Peter R.; Skrutskie, M. F.; Griffith, Roger L.; Marsh, Kenneth A.

    2015-05-10

    We present a sample of brown dwarfs identified with the Wide-field Infrared Survey Explorer (WISE) for which we have obtained Hubble Space Telescope (HST) Wide Field Camera 3 (WFC3) near-infrared grism spectroscopy. The sample (22 in total) was observed with the G141 grism covering 1.10–1.70 μm, while 15 were also observed with the G102 grism, which covers 0.90–1.10 μm. The additional wavelength coverage provided by the G102 grism allows us to (1) search for spectroscopic features predicted to emerge at low effective temperatures (e.g.,ammonia bands) and (2) construct a smooth spectral sequence across the T/Y boundary. We find no evidence of absorption due to ammonia in the G102 spectra. Six of these brown dwarfs are new discoveries, three of which are found to have spectral types of T8 or T9. The remaining three, WISE J082507.35+280548.5 (Y0.5), WISE J120604.38+840110.6 (Y0), and WISE J235402.77+024015.0 (Y1), are the 19th, 20th, and 21st spectroscopically confirmed Y dwarfs to date. We also present HST grism spectroscopy and reevaluate the spectral types of five brown dwarfs for which spectral types have been determined previously using other instruments.

  16. Using Wide-Field Meteor Cameras to Actively Engage Students in Science

    NASA Astrophysics Data System (ADS)

    Kuehn, D. M.; Scales, J. N.

    2012-08-01

    Astronomy has always afforded teachers an excellent topic to develop students' interest in science. New technology allows the opportunity to inexpensively outfit local school districts with sensitive, wide-field video cameras that can detect and track brighter meteors and other objects. While the data-collection and analysis process can be mostly automated by software, there is substantial human involvement that is necessary in the rejection of spurious detections, in performing dynamics and orbital calculations, and the rare recovery and analysis of fallen meteorites. The continuous monitoring allowed by dedicated wide-field surveillance cameras can provide students with a better understanding of the behavior of the night sky including meteors and meteor showers, stellar motion, the motion of the Sun, Moon, and planets, phases of the Moon, meteorological phenomena, etc. Additionally, some students intrigued by the possibility of UFOs and "alien visitors" may find that actual monitoring data can help them develop methods for identifying "unknown" objects. We currently have two ultra-low light-level surveillance cameras coupled to fish-eye lenses that are actively obtaining data. We have developed curricula suitable for middle or high school students in astronomy and earth science courses and are in the process of testing and revising our materials.

  17. WPOL: a DSSD-based hard x-ray wide field imager and polarimeter

    NASA Astrophysics Data System (ADS)

    Laurent, P.; Bertoli, W.; Breelle, E.; Dolgorouky, Y.; Gouiffès, C.; Khalil, M.; Limousin, O.; Lebrun, F.; Rodriguez, J.

    2014-07-01

    WPOL (Wide field camera with POLarimetry) is a wide field camera which aims to monitor the X-ray/low gamma-ray sources and measures their polarimetric properties. This camera will be operated in space to trigger a main instrument in case of transient events (gamma-ray bursts, black hole binaries state transition, supernovae, …) and to map the Xray/ gamma-ray polarized sources of the Galaxy, which has never been done up to now. It will be proposed, as an accompanying instrument, in the context of the next medium mission ESA call (M4). The concept of the instrument is based upon a coded mask imaging with a detector unit composed of two planes of Silicon double sided stripped detectors (DSSD), a passive collimator and a tungsten mask. Mapping is done on the first plane through mask imaging and polarization is measured by studying Compton scattering events between the two planes. The source direction in the sky being known through the mask pattern projected on the detector plane, and the scattered photon direction being measured between the two planes, only the determination of the first energy deposit is needed to compute the whole Compton scattering kinetics and in particular, to determine the source photon energy

  18. Delivery, installation, on-sky verification of the Hobby Eberly Telescope wide field corrector

    NASA Astrophysics Data System (ADS)

    Lee, Hanshin; Hill, Gary J.; Good, John M.; Vattiat, Brian L.; Shetrone, Matthew; Kriel, Herman; Martin, Jerry; Schroeder, Emily; Oh, Chang Jin; Frater, Eric; Smith, Bryan; Burge, James H.

    2016-08-01

    The Hobby-Eberly Telescope (HET)†, located in West Texas at the McDonald Observatory, operates with a fixed segmented primary (M1) and has a tracker, which moves the prime-focus corrector and instrument package to track the sidereal and non-sidereal motions of objects. We have completed a major multi-year upgrade of the HET that has substantially increased the pupil size to 10 meters and the field of view to 22 arcminutes by deploying the new Wide Field Corrector (WFC), new tracker system, and new Prime Focus Instrument Package (PFIP). The focus of this paper is on the delivery, installation, and on-sky verification of the WFC. We summarize the technical challenges encountered and resolutions to overcome such challenges during the construction of the system. We then detail the transportation from Tucson to the HET, on-site ground verification test results, post-installation static alignment among the WFC, PFIP, and M1, and on-sky verification of alignment and image quality via deploying multiple wavefront sensors across 22 arcminutes field of view. The new wide field HET will feed the revolutionary new integral field spectrograph called VIRUS, in support of the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX), a new low resolution spectrograph (LRS2), an upgraded high resolution spectrograph (HRS2), and later the Habitable Zone Planet Finder (HPF).

  19. The gamma-ray blazar quest: new optical spectra, state of art and future perspectives

    NASA Astrophysics Data System (ADS)

    Massaro, F.; Álvarez Crespo, N.; D'Abrusco, R.; Landoni, M.; Masetti, N.; Ricci, F.; Milisavljevic, D.; Paggi, A.; Chavushyan, V.; Jiménez-Bailón, E.; Patiño-Álvarez, V.; Strader, J.; Chomiuk, L.; La Franca, F.; Smith, Howard A.; Tosti, G.

    2016-10-01

    We recently developed a procedure to recognize γ-ray blazar candidates within the positional uncertainty regions of the unidentified/unassociated γ-ray sources (UGSs). Such procedure was based on the discovery that Fermi blazars show peculiar infrared colors. However, to confirm the real nature of the selected candidates, optical spectroscopic data are necessary. Thus, we performed an extensive archival search for spectra available in the literature in parallel with an optical spectroscopic campaign aimed to reveal and confirm the nature of the selected γ-ray blazar candidates. Here, we first search for optical spectra of a selected sample of γ-ray blazar candidates that can be potential counterparts of UGSs using the Sloan Digital Sky Survey (SDSS DR12). This search enables us to update the archival search carried out to date. We also describe the state-of-art and the future perspectives of our campaign to discover previously unknown γ-ray blazars.

  20. ISS-Lobster: a low-cost wide-field x-ray transient detector on the ISS

    NASA Astrophysics Data System (ADS)

    Camp, Jordan; Barthelmy, Scott; Petre, Rob; Gehrels, Neil; Marshall, Francis; Ptak, Andy; Racusin, Judith

    2015-05-01

    ISS-Lobster is a wide-field X-ray transient detector proposed to be deployed on the International Space Station. Through its unique imaging X-ray optics that allow a 30 deg by 30 deg FoV, a 1 arc min position resolution and a 1.6x10-11 erg/(sec cm2) sensitivity in 2000 sec, ISS-Lobster will observe numerous events per year of X-ray transients related to compact objects, including: tidal disruptions of stars by supermassive black holes, supernova shock breakouts, neutron star bursts and superbursts, high redshift Gamma-Ray Bursts, and perhaps most exciting, X-ray counterparts of gravitational wave detections involving stellar mass and possibly supermassive black holes. The mission includes a 3-axis gimbal system that allows fast Target of Opportunity pointing, and a small gamma-ray burst monitor. In this article we focus on ISS-Lobster measurements of X-ray counterparts of detections by the world-wide ground-based gravitational wave network.

  1. Impact of Cn2 profile on tomographic reconstruction performance: application to E-ELT wide field AO systems

    NASA Astrophysics Data System (ADS)

    Costille, A.; Fusco, T.

    2012-07-01

    New techniques of Adaptive Optics (AO), generically called Wide Field AO, have been developed in the frame of the design study for new instruments for Extremely Large Telescopes (ELI). Concepts such as Multi-Conjugate AO are based on a tomographic reconstruction of the turbulent volume followed by a projection onto DM(s) in order to ensure a good correction in a large Field of View. These systems require a 3D phase reconstruction and a statistical representation of the turbulent volume through the knowledge of the Cn2 profile, which has a strong impact on performance. We focus our study on the analysis of the impact of the structure and the parameters, which define the Cn2 profile, on the performance of a given tomographic system for an ELI. In this article, we perform simulation to emphasize the terms which are directly linked to the knowledge of the true input Cn2 profile, which simulates the input turbulent perturbations, and to the Cn2 profile which is used as a model in the reconstruction process. We determine and discuss the level of the accuracy needed on the Cn2 profile to limit the tomographic error term and to ensure a good performance. We show that a good sampling of the input turbulence is required to ensure performance of the system.

  2. Wide-field imaging and flow cytometric analysis of cancer cells in blood by fluorescent nanodiamond labeling and time gating

    PubMed Central

    Hui, Yuen Yung; Su, Long-Jyun; Chen, Oliver Yenjyh; Chen, Yit-Tsong; Liu, Tzu-Ming; Chang, Huan-Cheng

    2014-01-01

    Nanodiamonds containing high density ensembles of negatively charged nitrogen-vacancy (NV−) centers are promising fluorescent biomarkers due to their excellent photostability and biocompatibility. The NV− centers in the particles have a fluorescence lifetime of up to 20 ns, which distinctly differs from those (<10 ns) of cell and tissue autofluorescence, making it possible to achieve background-free detection in vivo by time gating. Here, we demonstrate the feasibility of using fluorescent nanodiamonds (FNDs) as optical labels for wide-field time-gated fluorescence imaging and flow cytometric analysis of cancer cells with a nanosecond intensified charge-coupled device (ICCD) as the detector. The combined technique has allowed us to acquire fluorescence images of FND-labeled HeLa cells in whole blood covered with a chicken breast of ~0.1-mm thickness at the single cell level, and to detect individual FND-labeled HeLa cells in blood flowing through a microfluidic device at a frame rate of 23 Hz, as well as to locate and trace FND-labeled lung cancer cells in the blood vessels of a mouse ear. It opens a new window for real-time imaging and tracking of transplanted cells (such as stem cells) in vivo. PMID:24994610

  3. Wide-field tracking of moving objects with a compact multi-object dispersed fixed-delay interferometer

    NASA Astrophysics Data System (ADS)

    Ge, Jian; Wan, Xiaoke; Myers, Derek; Powell, Scott

    2012-09-01

    We present a new concept for a Doppler imaging remote sensing instrument to track moving objects within a wide field of view using a compact multi-object Dispersed Fixed-Delay Interferometer (DFDI). The instrument is a combination of a Michelson type interferometer with a fixed optical delay and a medium resolution spectrograph. This takes advantage of the strength of the DFDI approach over the traditional cross-dispersed echelle spectrograph approach for high radial velocity (RV) precision measurements: multi-object capability, high throughput and a compact design. The combination of a fiber integral field unit (IFU) with a DFDI instrument allows simultaneous sampling of all of the objects within the observing field of view (FOV) to provide differential RV measurements of moving objects over background objects. Due to the three dimensional nature of the IFU spectroscopy the object location and spectral features can be simultaneously acquired. With the addition of RV signals to the measurements, this approach allows precise extraction of trajectories and spectral properties of moving objects (such as space debris and near Earth Objects (NEOs)) through sequential monitoring of moving objects. Measurement results from moving objects in a lab as well as moving cars in a field using this innovative approach are reported.

  4. Wide-field imaging and flow cytometric analysis of cancer cells in blood by fluorescent nanodiamond labeling and time gating

    NASA Astrophysics Data System (ADS)

    Hui, Yuen Yung; Su, Long-Jyun; Chen, Oliver Yenjyh; Chen, Yit-Tsong; Liu, Tzu-Ming; Chang, Huan-Cheng

    2014-07-01

    Nanodiamonds containing high density ensembles of negatively charged nitrogen-vacancy (NV-) centers are promising fluorescent biomarkers due to their excellent photostability and biocompatibility. The NV- centers in the particles have a fluorescence lifetime of up to 20 ns, which distinctly differs from those (<10 ns) of cell and tissue autofluorescence, making it possible to achieve background-free detection in vivo by time gating. Here, we demonstrate the feasibility of using fluorescent nanodiamonds (FNDs) as optical labels for wide-field time-gated fluorescence imaging and flow cytometric analysis of cancer cells with a nanosecond intensified charge-coupled device (ICCD) as the detector. The combined technique has allowed us to acquire fluorescence images of FND-labeled HeLa cells in whole blood covered with a chicken breast of ~0.1-mm thickness at the single cell level, and to detect individual FND-labeled HeLa cells in blood flowing through a microfluidic device at a frame rate of 23 Hz, as well as to locate and trace FND-labeled lung cancer cells in the blood vessels of a mouse ear. It opens a new window for real-time imaging and tracking of transplanted cells (such as stem cells) in vivo.

  5. Automated Astrometric Analysis of Satellite Observations using Wide-field Imaging

    NASA Astrophysics Data System (ADS)

    Skuljan, J.; Kay, J.

    2016-09-01

    An observational trial was conducted in the South Island of New Zealand from 24 to 28 February 2015, as a collaborative effort between the United Kingdom and New Zealand in the area of space situational awareness. The aim of the trial was to observe a number of satellites in low Earth orbit using wide-field imaging from two separate locations, in order to determine the space trajectory and compare the measurements with the predictions based on the standard two-line elements. This activity was an initial step in building a space situational awareness capability at the Defence Technology Agency of the New Zealand Defence Force. New Zealand has an important strategic position as the last land mass that many satellites selected for deorbiting pass before entering the Earth's atmosphere over the dedicated disposal area in the South Pacific. A preliminary analysis of the trial data has demonstrated that relatively inexpensive equipment can be used to successfully detect satellites at moderate altitudes. A total of 60 satellite passes were observed over the five nights of observation and about 2600 images were collected. A combination of cooled CCD and standard DSLR cameras were used, with a selection of lenses between 17 mm and 50 mm in focal length, covering a relatively wide field of view of 25 to 60 degrees. The CCD cameras were equipped with custom-made GPS modules to record the time of exposure with a high accuracy of one millisecond, or better. Specialised software has been developed for automated astrometric analysis of the trial data. The astrometric solution is obtained as a two-dimensional least-squares polynomial fit to the measured pixel positions of a large number of stars (typically 1000) detected across the image. The star identification is fully automated and works well for all camera-lens combinations used in the trial. A moderate polynomial degree of 3 to 5 is selected to take into account any image distortions introduced by the lens. A typical RMS

  6. Automated algorithm for actinic cheilitis diagnosis by wide-field fluorescence imaging.

    PubMed

    Cosci, Alessandro; Takahama, Ademar; Correr, Wagner Rafael; Azevedo, Rebeca Souza; Fontes, Karla Bianca Fernandes da Costa; Kurachi, Cristina

    2016-10-01

    Actinic cheilitis (AC) is a disease caused by prolonged and cumulative sun exposure that mostly affects the lower lip, which can progress to a lip squamous cell carcinoma. Routine diagnosis relies on clinician experience and training. We investigated the diagnostic efficacy of wide-field fluorescence imaging coupled to an automated algorithm for AC recognition. Fluorescence images were acquired from 57 patients with confirmed AC and 46 normal volunteers. Three different algorithms were employed: two based on the emission characteristics of local heterogeneity, entropy and intensity range, and one based on the number of objects after K-mean clustering. A classification model was obtained using a fivefold cross correlation algorithm. Sensitivity and specificity rates were 86% and 89.1%, respectively.

  7. Nonlinear structured-illumination microscopy: Wide-field fluorescence imaging with theoretically unlimited resolution

    PubMed Central

    Gustafsson, Mats G. L.

    2005-01-01

    Contrary to the well known diffraction limit, the fluorescence microscope is in principle capable of unlimited resolution. The necessary elements are spatially structured illumination light and a nonlinear dependence of the fluorescence emission rate on the illumination intensity. As an example of this concept, this article experimentally demonstrates saturated structured-illumination microscopy, a recently proposed method in which the nonlinearity arises from saturation of the excited state. This method can be used in a simple, wide-field (nonscanning) microscope, uses only a single, inexpensive laser, and requires no unusual photophysical properties of the fluorophore. The practical resolving power is determined by the signal-to-noise ratio, which in turn is limited by photobleaching. Experimental results show that a 2D point resolution of <50 nm is possible on sufficiently bright and photostable samples. PMID:16141335

  8. An integrated image processing platform designed for Chinese GF-1 wide field view data

    NASA Astrophysics Data System (ADS)

    Li, Zhishan; Shi, Runhe; Liu, Chaoshun; Chen, Maosi

    2016-09-01

    The Wide Field View (WFV), a space borne multi-spectral sensor onboard the Chinese GaoFen-1 (GF-1) satellite from the China High-resolution Earth Observation System, is operating in orbit dedicating to providing Earth observation with decametric spatial resolution, high temporal resolution and wide coverage for environment monitoring purpose. The objective of this study is to present an integrated image processing and environment monitoring platform specifically for GF-1 WFV data. The platform is developed with a multi-layer architecture and C/S structure, which primarily consists of image pre-processing, environment monitoring, data visualization, and results output modules. The client application was created by using C# whereas IDL was used to develop image processing and other relevant algorithms. This paper focuses mainly on the overall design of the platform and related key techniques. The platform has been implemented as a stand-alone application, and successfully implemented in real world environment monitoring studies.

  9. Readout electronics for the Wide Field of view Cherenkov/Fluorescence Telescope Array

    NASA Astrophysics Data System (ADS)

    Zhang, J.; Zhang, S.; Zhang, Y.; Zhou, R.; Bai, L.; Zhang, J.; Huang, J.; Yang, C.; Cao, Z.

    2015-08-01

    The aim of the Large High Altitude Air Shower Observatory (LHAASO), supported by IHEP of the Chinese Academy of Sciences, is a multipurpose project with a complex detectors array for high energy gamma ray and cosmic ray detection. The Wide Field of view Cherenkov Telescope Array (WFCTA), as one of the components of the LHAASO project, aim to tag each primary particle that causes an air shower. The WFCTA is a portable telescope array used to detect cosmic ray spectra. The design of the readout electronics of the WFCTA is described in this paper Sixteen photomultiplier tubes (PMTs), together with their readout electronics are integrated into a single sub-cluster. To maintain good resolution and linearity over a wide dynamic range, a dual-gain amplification configuration on an analog board is used The digital board contains two 16channel 14-bit, 50 Msps analog-to-digital converters (ADC) and its power consumption, noise level, and relative deviation are all tested.

  10. Geometry of the Hubble Space Telescope Wide Field/Planetary Camera field

    NASA Technical Reports Server (NTRS)

    Gould, Andrew; Yanny, Brian

    1994-01-01

    We present a solution for the relative positions and orientations of the four charge coupled device (CCD) chips on the Hubble Space Telescope (HST) Planetary Camera (PC). An accurate solution is required when matching HST images with ground-based images or with one another. The solution is accurate to about 2/3 PC pixel or about .03 sec, a tenfold improvement over the best previous solution. The CCDs are rotated relative to one another by up to 1 deg. The solution is based on images taken between December 1990 and June 1992 and is stable over that entire period. We also present a solution for the relative positions and orientations of the four CCD chips on the HST Wide Field Camera (WFC). This solution is accurate to about 1/2 WFC pixel or about .05 sec.

  11. Performance analysis of a filtered wide field-of-view radiometer for earth radiation budget measurements

    NASA Technical Reports Server (NTRS)

    Cooper, J. E.; Luther, M. R.

    1978-01-01

    The proposed Earth Radiation Budget Satellite System (ERBSS) of the 1980's will include a wide field-of-view (WFOV) fixed axes earth radiator discriminator consisting of a shortwave channel and a total (unfiltered) channel. The broadband spectral isolation required for the shortwave channel is achieved by use of a hemispherical fused silica (Suprasil W) dome filter placed in front of a wire wound thermopile radiation detector. A description is presented of the thermal response of the single-fused silica dome filter in the ERBSS WFOV shortwave channel conceptual design and the impact of that response on the channel measurement. Results from design definition and performance analysis studies are included. Problems associated with achieving the desired levels of confidence in a high accuracy filtered, WFOV radiometer are discussed. Design approaches, ground calibration, and data reduction techniques which minimize measurement uncertainties are explained.

  12. The Wide Field/Planetary Camera 2 (WFPC-2) molecular adsorber

    NASA Technical Reports Server (NTRS)

    Barengoltz, Jack; Moore, Sonya; Soules, David; Voecks, Gerald

    1995-01-01

    A device has been developed at the Jet Propulsion Laboratory, California Institute of Technology, for the adsorption of contaminants inside a space instrument during flight. The molecular adsorber was developed for use on the Wide Field Planetary Camera 2, and it has been shown to perform at its design specifications in the WFPC-2. The basic principle of the molecular adsorber is a zeolite-coated ceramic honeycomb. The arrangement is efficient for adsorption and also provides the needed rigidity to retain the special zeolite coating during the launch vibrational environment. The adsorber, on other forms, is expected to be useful for all flight instruments sensitive to internal sources of contamination. Typically, some internal contamination is unavoidable. A common design solution is to increase the venting to the exterior. However, for truly sensitive instruments, the external contamination environment is more severe. The molecular adsorber acts as a one-way vent to solve this problem. Continued development is planned for this device.

  13. Science yield estimate with the Wide-Field Infrared Survey Telescope coronagraph

    NASA Astrophysics Data System (ADS)

    Traub, Wesley A.; Breckinridge, James; Greene, Thomas P.; Guyon, Olivier; Jeremy Kasdin, N.; Macintosh, Bruce

    2016-01-01

    The coronagraph instrument (CGI) on the Wide-Field Infrared Survey Telescope will directly image and spectrally characterize planets and circumstellar disks around nearby stars. Here we estimate the expected science yield of the CGI for known radial-velocity (RV) planets and potential circumstellar disks. The science return is estimated for three types of coronagraphs: the hybrid Lyot and shaped pupil are the currently planned designs, and the phase-induced amplitude apodizing complex mask coronagraph is the backup design. We compare the potential performance of each type for imaging as well as spectroscopy. We find that the RV targets can be imaged in sufficient numbers to produce substantial advances in the science of nearby exoplanets. To illustrate the potential for circumstellar disk detections, we estimate the brightness of zodiacal-type disks, which could be detected simultaneously during RV planet observations.

  14. Studies on wide-field-of-view multiphoton imaging using the flexible clinical multiphoton tomograph MPTflex

    NASA Astrophysics Data System (ADS)

    Weinigel, Martin; Breunig, Hans Georg; Fischer, Peter; Kellner-Höfer, Marcel; Bückle, Rainer; König, Karsten

    2012-03-01

    Multiphoton imaging systems are capable of high-resolution 3-D image acquisition of deep tissue. A first commercially available CE-certified biomedical system for subcelluar resolution of human skin has been launched by JenLab company with the DermaInspectR in 2002. The demand for more flexibility caused the development of the MPTflexR, which provides an increased flexibility and accessibility especially for clinical and cosmetic examinations. However the high resolution of clinical multiphoton tomographs are adherent with a small field-of-view (FOV) of about 360×360μm2. Especially time-consuming is the relocation of areas of interest (AOI) like lesions, sweat glands or hair shafts during a multiphoton examination. This limitation can be be overcome by macroscopic large-area (wide-field-ofview) multiphoton tomography, which is tested first within this work.

  15. Multi-modal digital holographic microscopy for wide-field fluorescence and 3D phase imaging

    NASA Astrophysics Data System (ADS)

    Quan, Xiangyu; Xia, Peng; Matoba, Osamu; Nitta, Koichi; Awatsuji, Yasuhiro

    2016-03-01

    Multi-modal digital holographic microscopy is a combination of epifluorescence microscopy and digital holographic microscopy, the main function of which is to obtain images from fluorescence intensity and quantified phase contrasts, simultaneously. The proposed system is mostly beneficial to biological studies, with the reason that often the studies are depending on fluorescent labeling techniques to detect certain intracellular molecules, while phase information reflecting properties of unstained transparent elements. This paper is presenting our latest researches on applications such as randomly moving micro-fluorescent beads and living cells of Physcomitrella patens. The experiments are succeeded on obtaining a succession of wide-field fluorescent images and holograms from micro-beads, and different depths focusing is realized via numerical reconstruction. Living cells of Physcomitrella patens are recorded in the static manner, the reconstruction distance indicates thickness of cellular structure. These results are implementing practical applications toward many biomedical science researches.

  16. Satellite Detection in Advanced Camera for Surveys/Wide Field Channel Images

    NASA Astrophysics Data System (ADS)

    Borncamp, D.; Lim, Pey Lian

    2016-01-01

    This document explains the process by which satellite trails can be found within individual chips of an Advanced Camera for Surveys (ACS) Wide Field Channel (WFC) image. Since satellites are transient and sporadic events, we used the Hubble Frontier Fields (HFF) dataset which is manually checked for satellite trails has been used as a truth set to verify that the method in this document does a complete job without a high false positive rate. This document also details the process of producing a mask that will update data quality information to inform users where the trail traverses the image and properly account for the affected pixels. Along with this document, the Python source code used to detect and mask satellite trails will be released to users with as a stand-alone product within the STSDAS acstools package.

  17. Morphological analysis of Bacillux polymyxa colonies: digital image analysis in wide-field microscopy

    NASA Astrophysics Data System (ADS)

    Guerrero, Lina M.; Plata G., Arturo; Rincón C., Giovanna; Gutiérrez A., Henry; Plata, Alexandra

    2013-11-01

    In the last twenty years the growth of bacterial colonies has been studied experimentally using images with different growth patterns, but the resolution of those images is in areas of tenths of microns without range information. On the other hand, theoretical studies considering the bacteria as systems with collective behavior controlled by a reduced number of parameters have been developed. The present work aims to study morphological and dynamic growth of Bacillus polymyxa colonies by the technique of digital image analysis in wide-field microscopy, which provides high resolution, both in texture and topography. Getting a three-dimensional behavior of dynamic biological systems is useful to create structures and materials with different physical and biological properties for industrial applications.

  18. Ultra-wide field retinal imaging in detection, classification, and management of diabetic retinopathy.

    PubMed

    Soliman, Ahmed Z; Silva, Paolo S; Aiello, Lloyd Paul; Sun, Jennifer K

    2012-01-01

    Current ultra-wide field (UWF) retinal imaging systems utilize scanning laser ophthalmoscope technology combined with an ellipsoidal mirror to capture up to 200 degrees of the retina in a single image. When compared with mydriatic ETDRS-protocol, 7 standard field photographs and clinical examination, nonmydriatic UWF images appear to have excellent agreement in allowing the detection and classification of diabetic retinopathy (DR), although larger, definitive validation studies are still forthcoming. UWF imaging and angiography allow visualization of peripheral retinal nonperfusion, vascular leakage and neovascularization in patients with DR that may not be captured on 7 standard fields. Prospective randomized controlled trials are needed to evaluate whether modified laser treatment algorithms based on improved visualization of the retinal periphery might improve patient outcomes. Nonmydriatic UWF imaging has potential applications for ocular diabetic telehealth programs, but validation of newer, more portable, and more affordable UWF imaging models is needed.

  19. Near infrared FRET using wide-field fluorescence lifetime imaging in live animals

    NASA Astrophysics Data System (ADS)

    Zhao, Lingling; Abe, Ken; Barroso, Margarida; Intes, Xavier

    2013-06-01

    One of the challenges in anti-cancer drug delivery systems is to quantitatively discriminate non-specific receptorindependent tumor accumulation from receptor-mediated uptake into the tumor cells. To overcome this challenge, we develop a new near infrared fluorescence resonance energy transfer fluorescence lifetime imaging (NIR FRET FLIM) technique with wide-field illumination strategies to validate and characterize cellular uptake in both cancer cells and normal cells with different donor-acceptor ratios in vitro and in vivo. Our results demonstrate that NIR FRET FLIM can quantitatively distinguish receptor-bound from unbound donor in live animals with high sensitivity and high accuracy. Thus, it has a great potential for the quantitative detection of targeted delivery systems for diagnostic and therapeutic use.

  20. Stellar photometry with the Wide Field/Planetary Camera of the Hubble Space Telescope

    SciTech Connect

    Holtzman, J.A. )

    1990-07-01

    Simulations of Wide Field/Planetary Camera (WF/PC) images are analyzed in order to discover the most effective techniques for stellar photometry and to evaluate the accuracy and limitations of these techniques. The capabilities and operation of the WF/PC and the simulations employed in the study are described. The basic techniques of stellar photometry and methods to improve these techniques for the WF/PC are discussed. The correct parameters for star detection, aperture photometry, and point-spread function (PSF) fitting with the DAOPHOT software of Stetson (1987) are determined. Consideration is given to undersampling of the stellar images by the detector; variations in the PSF; and the crowding of the stellar images. It is noted that, with some changes DAOPHOT, is able to generate photometry almost to the level of photon statistics. 10 refs.

  1. Australian SKA Pathfinder: A High-Dynamic Range Wide-Field of View Survey Telescope

    NASA Astrophysics Data System (ADS)

    DeBoer, D. R.; Gough, R. G.; Bunton, J. D.; Cornwell, T. J.; Beresford, R. J.; Johnston, S.; Feain, I. J.; Schinckel, A. E.; Jackson, C. A.; Kesteven, M. J.; Chippendale, A.; Hampson, G. A.; O'Sullivan, J. D.; Hay, S. G.; Jacka, C. E.; Sweetnam, T. W.; Storey, M. C.; Ball, L.; Boyle, B. J.

    2009-08-01

    The Australia SKA Pathfinder (ASKAP) is a new telescope under development as a world-class high-dynamic-range wide-field-of-view survey instrument. It will utilize focal plane phased array feeds on the 36 12-m antennas that will compose the array. The large amounts of data present a huge computing challenge, and ASKAP will store data products in an archive after near real-time pipeline processing. This powerful instrument will be deployed at a new radio-quiet observatory, the Murchison Radio-astronomy Observatory in the midwest region of Western Australia, to enable sensitive surveys of the entire sky to address some of the big questions in contemporary physics. As a pathfinder for the SKA, ASKAP will demonstrate field of view enhancement and computing/processing technology as well as the operation of a large-scale radio array in a remote and radio-quiet region of Australia.

  2. Wide-field FTIR microscopy using mid-IR pulse shaping

    PubMed Central

    Serrano, Arnaldo L.; Ghosh, Ayanjeet; Ostrander, Joshua S.; Zanni, Martin T.

    2015-01-01

    We have developed a new table-top technique for collecting wide-field Fourier transform infrared (FTIR) microscopic images by combining a femtosecond pulse shaper with a mid-IR focal plane array. The pulse shaper scans the delay between a pulse pair extremely rapidly for high signal-to-noise, while also enabling phase control of the individual pulses to under-sample the interferograms and subtract background. Infrared absorption images were collected for a mixture of W(CO)6 or Mn2(CO)10 absorbed polystyrene beads, demonstrating that this technique can spatially resolve chemically distinct species. The images are sub-diffraction limited, as measured with a USAF test target patterned on CaF2 and verified with scalar wave simulations. We also find that refractive, rather than reflective, objectives are preferable for imaging with coherent radiation. We discuss this method with respect to conventional FTIR microscopes. PMID:26191843

  3. Current status of the Hobby-Eberly Telescope wide field upgrade

    NASA Astrophysics Data System (ADS)

    Hill, Gary J.; Booth, John A.; Cornell, Mark E.; Good, John M.; Gebhardt, Karl; Kriel, Herman J.; Lee, Hanshin; Leck, Ron; Moreira, Walter; MacQueen, Phillip J.; Perry, Dave M.; Rafal, Marc D.; Rafferty, Tom H.; Ramiller, Chuck; Savage, Richard D.; Taylor, Charles A.; Vattiat, Brian L.; Ramsey, Lawrence W.; Beno, Joseph H.; Beets, Timothy A.; Esguerra, Jorge D.; Häuser, Marco; Hayes, Richard J.; Heisler, James T.; Soukup, Ian M.; Zierer, Joseph J.; Worthington, Michael S.; Mollison, Nicholas T.; Wardell, Douglas R.; Wedeking, Gregory A.

    2012-09-01

    The Hobby-Eberly Telescope (HET) is an innovative large telescope of 9.2 meter aperture, located in West Texas at the McDonald Observatory (MDO). The HET operates with a fixed segmented primary and has a tracker which moves the four-mirror corrector and prime focus instrument package to track the sidereal and non-sidereal motions of objects. A major upgrade of the HET is in progress that will increase the pupil size to 10 meters and the field of view to 22' by replacing the corrector, tracker and prime focus instrument package. In addition to supporting the existing suite of instruments, this wide field upgrade will feed a revolutionary new integral field spectrograph called VIRUS, in support of the Hobby-Eberly Telescope Dark Energy Experiment (HETDEXχ). This paper discusses the current status of this upgrade.

  4. The Wide-Field Nearby Galaxy-Cluster Survey (WINGS) and Its Extension OMEGAWINGS

    NASA Astrophysics Data System (ADS)

    Poggianti, B. M.; Fasano, G.; Bettoni, D.; Cava, A.; Couch, W.; D'Onofrio, M.; Dressler, A.; Fritz, J.; Kjaergaard, P.; Gullieuszik, M.; Moles, M.; Moretti, A.; Omizzolo, A.; Paccagnella, A.; Varela, J.; Vulcani, B.

    WINGS is a wide-field multi-wavelength survey of 76 X-ray selected clusters at low redshift. The WINGS database has been used for a variety of cluster and cluster galaxy studies, investigating galaxy star formation, morphologies, structure, stellar mass functions and other properties. We present the recent wider-field extension of WINGS, OMEGAWINGS, conducted with OmegaCAM@VST and AAOmega@AAT. We show two of our latest results regarding jellyfish galaxies and galaxy sizes. OMEGAWINGS has allowed the first systematic search of galaxies with signs of ongoing ram pressure stripping (jellyfishes), yielding a catalog of ˜ 240 galaxies in 41 clusters. We discuss the first results obtained from this sample and the prospects for integral field data. Finally, we summarize our results regarding the discovery of compact massive galaxies at low redshift, their properties, dependence on environment and the implications for the evolution of galaxy sizes from high- to low-z.

  5. SpIOMM and SITELLE: Wide-field Imaging FTS for the Study of Galaxy Evolution

    NASA Astrophysics Data System (ADS)

    Drissen, Laurent; Bernier, Anne-Pier; Robert, Carmelle; Robert

    2011-12-01

    SpIOMM, a wide-field Imaging Fourier Transform Spectrometer attached to the Mont Mégantic 1.6-m telescope, is capable of obtaining the visible spectrum of every source of light in a 12 arcminute field of view, with a spectral resolution ranging from R = 1 (wide-band image) to R = 25 000, resulting in 1.7 million spectra with a spatial resolution of one arcsecond. SITELLE will be a similar instrument attached to the Canada-France-Hawaii telescope, and will be in operation in early 2013. We present a short description of these instruments and illustrate their capabilities to study nearby galaxies with the results of a data cube of M51.

  6. Commissioning of a medical accelerator photon beam Monte Carlo simulation using wide-field profiles

    NASA Astrophysics Data System (ADS)

    Pena, J.; Franco, L.; Gómez, F.; Iglesias, A.; Lobato, R.; Mosquera, J.; Pazos, A.; Pardo, J.; Pombar, M.; Rodríguez, A.; Sendón, J.

    2004-11-01

    A method for commissioning an EGSnrc Monte Carlo simulation of medical linac photon beams through wide-field lateral profiles at moderate depth in a water phantom is presented. Although depth-dose profiles are commonly used for nominal energy determination, our study shows that they are quite insensitive to energy changes below 0.3 MeV (0.6 MeV) for a 6 MV (15 MV) photon beam. Also, the depth-dose profile dependence on beam radius adds an additional uncertainty in their use for tuning nominal energy. Simulated 40 cm × 40 cm lateral profiles at 5 cm depth in a water phantom show greater sensitivity to both nominal energy and radius. Beam parameters could be determined by comparing only these curves with measured data.

  7. Palm-size wide-field Fourier spectroscopic imager with uncooled infrared microbolometer arrays for smartphone

    NASA Astrophysics Data System (ADS)

    Kawashima, Natsumi; Suzuki, Yo; Qi, Wei; Hosono, Satsuki; Saito, Tsubasa; Ogawa, Satoshi; Sato, Shun; Fujiwara, Masaru; Nishiyama, Akira; Wada, Kenji; Tanaka, Naotaka; Ishimaru, Ichiro

    2015-03-01

    We proposed the imaging-type 2-dimensional Fourier spectroscopy that is a near-common-path interferometer with strong robustness against mechanical vibrations. We introduced the miniature uncooled infrared microbolometer arrays for smartphone (e.g. product name: FILR ONE price: around 400USD). And we constructed the phase-shifter with the piezo impact drive mechanism (maker: Technohands.co.Ltd., stroke: 4.5mm, resolution: 0.01μm, size: 20mm, price: around 800USD). Thus, we realized the palm-size mid-infrared spectroscopic imager [size: L56mm×W69mm×H43mm weight: 500g]. And by using wide-angle lens as objective lens, the proposed method can obtain the wide-field 2- dimensional middle-infrared (wavelength: 7.5-13.5[μm]) spectroscopic imaging of radiation lights emitted from human bodies itself

  8. The filter and calibration wheel for the ATHENA wide field imager

    NASA Astrophysics Data System (ADS)

    Rataj, M.; Polak, S.; Palgan, T.; Kamisiński, T.; Pilch, A.; Eder, J.; Meidinger, N.; Plattner, M.; Barbera, M.; Parodi, G.; D'Anca, Fabio

    2016-07-01

    The planned filter and calibration wheel for the Wide Field Imager (WFI) instrument on Athena is presented. With four selectable positions it provides the necessary functions, in particular an UV/VIS blocking filter for the WFI detectors and a calibration source. Challenges for the filter wheel design are the large volume and mass of the subsystem, the implementation of a robust mechanism and the protection of the ultra-thin filter with an area of 160 mm square. This paper describes performed trade-offs based on simulation results and describes the baseline design in detail. Reliable solutions are envisaged for the conceptual design of the filter and calibration wheel. Four different variant with different position of the filter are presented. Risk mitigation and the compliance to design requirements are demonstrated.

  9. Wide-field endoscopic fluorescence imaging for gastrointestinal tumor detection with glucose analogue

    NASA Astrophysics Data System (ADS)

    He, Yun; Qu, Yawei; Bai, Jing; Liu, Haifeng

    2014-05-01

    The lack of functional information and targeted imaging in conventional white-light endoscopy leads to a high miss-rate of gastrointestinal tumor. The combination of near-infrared fluorescence imaging and endoscopy presents a promising approach. Here we introduce a new endoscopy method employing a home-made flexible wide-field epi-fluorescence endoscope, that can be inserted through the biopsy channel of a gastrointestinal endoscope, with the glucose analogue 2- DeoxyGlucosone as the near-infrared fluorescent probe. System characterization indicates a good sensitivity and linearity over a large field of view. Its capability of tumor identification and location is demonstrated with in-vivo imaging of xenografted tumor model.

  10. Design of a wide field far-UV spectrometer for a mission to Mars

    NASA Astrophysics Data System (ADS)

    Wishnow, Edward; Miller, Tim; Fillingim, Matthew; Edelstein, Jerry; Lillis, Robert; Korpela, Eric; England, Scott; Shourt, William Van; Siegmund, Oswald; McPhate, Jason; Courtade, Sasha; Curtis, David; Deighan, Justin; Chaffin, Michael; Harmoul, Abdullah S.; Al Matroushi, Hessa R.

    2016-07-01

    An imaging spectrometer for observations of the Martian corona and the Martian thermosphere is presented. The corona extends over 10 Martian radii and its measurement requires observations over a very wide field. The spectrometer covers the wavelength region 120-170 nm where this band includes coronal spectral lines of hydrogen Lyman alpha and oxygen, and thermospheric spectral lines from atomic oxygen and carbon and the 4th positive band of CO. Stellar occultation observations will provide atmospheric density measurements. These scientific requirements are fulfilled by an Offner-type spectrometer with a 110 degree instantaneous field of view and no moving mechanisms. Both the spectral and imaging resolution vary across the field, from higher resolution across the planet body, to lower resolution required at the diffuse outer parts of the corona. This Offner-type design has not been previously used in the FUV.

  11. Lessons Learned from the Wide Field Camera 3 TV1 and TV2 Thermal Vacuum Test Campaigns

    NASA Technical Reports Server (NTRS)

    Peabody, Hume; Stavely, Richard; Bast, William

    2008-01-01

    The Wide Field Camera 3 (WFC3) instrument has undergone two complete thermal vacuum tests (TV1 and TV2), during which valuable lessons were learned regarding test configuration, test execution, model capabilities, and modeling practices. The very complex thermal design of WFC3 produced a number of challenging aspects to ground testing with numerous ThermoElectric Coolers and heat pipes, not all of which were functional. Lessons learned during TV1 resulted in significant upgrades to the model capabilities and a change in the test environment approach for TV2. These upgrades proved invaluable during TV2 when pretest modeling assumptions proved to be false. Each of the lessons learned relate to one of two following broad statements: 1. Ensure the design can be tested and that the effect of non-flight like conditions is well understood, particularly with respect to non passive devices (TECs, Heat Pipes, etc) 2. Ensure that the model is sufficiently detailed and is capable of predicting off-nominal behavior and the power dissipation of any thermal devices, especially TECs This paper outlines a number of the lessons learned over these two test campaigns with respect to the thermal design, model, and test configuration and presents recommendations for future tests.

  12. An experiment in big data: storage, querying and visualisation of data taken from the Liverpool Telescope's wide field cameras

    NASA Astrophysics Data System (ADS)

    Barnsley, R. M.; Steele, Iain A.; Smith, R. J.; Mawson, Neil R.

    2014-07-01

    The Small Telescopes Installed at the Liverpool Telescope (STILT) project has been in operation since March 2009, collecting data with three wide field unfiltered cameras: SkycamA, SkycamT and SkycamZ. To process the data, a pipeline was developed to automate source extraction, catalogue cross-matching, photometric calibration and database storage. In this paper, modifications and further developments to this pipeline will be discussed, including a complete refactor of the pipeline's codebase into Python, migration of the back-end database technology from MySQL to PostgreSQL, and changing the catalogue used for source cross-matching from USNO-B1 to APASS. In addition to this, details will be given relating to the development of a preliminary front-end to the source extracted database which will allow a user to perform common queries such as cone searches and light curve comparisons of catalogue and non-catalogue matched objects. Some next steps and future ideas for the project will also be presented.

  13. The optical antenna system design research on earth integrative network laser link in the future

    NASA Astrophysics Data System (ADS)

    Liu, Xianzhu; Fu, Qiang; He, Jingyi

    2014-11-01

    Earth integrated information network can be real-time acquisition, transmission and processing the spatial information with the carrier based on space platforms, such as geostationary satellites or in low-orbit satellites, stratospheric balloons or unmanned and manned aircraft, etc. It is an essential infrastructure for China to constructed earth integrated information network. Earth integrated information network can not only support the highly dynamic and the real-time transmission of broadband down to earth observation, but the reliable transmission of the ultra remote and the large delay up to the deep space exploration, as well as provide services for the significant application of the ocean voyage, emergency rescue, navigation and positioning, air transportation, aerospace measurement or control and other fields.Thus the earth integrated information network can expand the human science, culture and productive activities to the space, ocean and even deep space, so it is the global research focus. The network of the laser communication link is an important component and the mean of communication in the earth integrated information network. Optimize the structure and design the system of the optical antenna is considered one of the difficulty key technologies for the space laser communication link network. Therefore, this paper presents an optical antenna system that it can be used in space laser communication link network.The antenna system was consisted by the plurality mirrors stitched with the rotational paraboloid as a substrate. The optical system structure of the multi-mirror stitched was simulated and emulated by the light tools software. Cassegrain form to be used in a relay optical system. The structural parameters of the relay optical system was optimized and designed by the optical design software of zemax. The results of the optimal design and simulation or emulation indicated that the antenna system had a good optical performance and a certain

  14. Precision Pointing for the Wide-Field Infrared Survey Telescope (WFIRST)

    NASA Technical Reports Server (NTRS)

    Stoneking, Eric; Hsu, Oscar; Welter, Gary

    2017-01-01

    The Wide-Field Infrared Survey Telescope (WFIRST) mission, scheduled for a mid-2020's launch, is currently in its definition phase. The mission is designed to investigate essential questions in the areas of dark energy, exoplanets, and infrared astrophysics. WFIRST will use a 2.4-meter primary telescope (same size as the Hubble Space Telescope's primary mirror) and two instruments: the Wide Field Instrument (WFI) and the Coronagraph Instrument (CGI). In order to ad-dress the critical science requirements, the WFIRST mission will conduct large-scale surveys of the infrared sky, requiring both agility and precision pointing (11.6 milli-arcsec stability, 14 milli-arcsec jitter). This paper describes some of the challenges this mission profile presents to the GNC subsystem, and some of the design elements chosen to accommodate those challenges. The high-galactic-latitude survey is characterized by 3-minute observations separated by slews ranging from 0.025 deg to 0.8 deg. The need for observation efficiency drives the slew and settle process to be as rapid as possible. A description of the shaped slew profile chosen to minimize excitation of structural oscillation, and the handoff from star tracker-gyro control to fine guidance sensor control is detailed. Also presented is the fine guidance sensor (FGS), which is integral with the primary instrument (WFI). The FGS is capable of tracking up to 18 guide stars, enabling robust FGS acquisition and precision pointing. To avoid excitation of observatory structural jitter, reaction wheel speeds are operationally maintained within set limits. In addition, the wheel balance law is designed to maintain 1-Hz separation between the wheel speeds to avoid reinforcing jitter excitation at any particular frequency. The wheel balance law and operational implications are described. Finally, the candidate GNC hardware suite needed to meet the requirements of the mission is presented.

  15. Precision Pointing for the Wide-Field Infrared Survey Telescope(WFIRST)

    NASA Technical Reports Server (NTRS)

    Stoneking, Eric T.; Hsu, Oscar C.; Welter, Gary

    2017-01-01

    The Wide-Field Infrared Survey Telescope (WFIRST) mission, scheduled for a mid-2020's launch, is currently in its definition phase. The mission is designed to investigate essential questions in the areas of dark energy, exoplanets, and infrared astrophysics. WFIRST will use a 2.4-meter primary telescope (same size as the Hubble Space Telescope's primary mirror) and two instruments: the Wide Field Instrument (WFI) and the Coronagraph Instrument (CGI). In order to address the critical science requirements, the WFIRST mission will conduct large-scale surveys of the infrared sky, requiring both agility and precision pointing (11.6 milli-arcsec stability, 14 milli-arcsec jitter). This paper describes some of the challenges this mission profile presents to the Guidance, Navigation, and Control (GNC) subsystem, and some of the design elements chosen to accommodate those challenges. The high-galactic-latitude survey is characterized by 3-minute observations separated by slews ranging from 0.025 deg to 0.8 deg. The need for observation efficiency drives the slew and settle process to be as rapid as possible. A description of the shaped slew profile chosen to minimize excitation of structural oscillation, and the handoff from star tracker-gyro control to fine guidance sensor control is detailed. Also presented is the fine guidance sensor (FGS), which is integral with the primary instrument (WFI). The FGS is capable of tracking up to 18 guide stars, enabling robust FGS acquisition and precision pointing. To avoid excitation of observatory structural jitter, reaction wheel speeds are operationally maintained within set limits. In addition, the wheel balance law is designed to maintain 1-Hz separation between the wheel speeds to avoid reinforcing jitter excitation at any particular frequency. The wheel balance law and operational implications are described. Finally, the candidate GNC hardware suite needed to meet the requirements of the mission is presented.

  16. Reaching the Diffraction Limit - Differential Speckle and Wide-Field Imaging for the WIYN Telescope

    NASA Technical Reports Server (NTRS)

    Scott, Nic J.; Howell, Steve; Horch, Elliott

    2016-01-01

    Speckle imaging allows telescopes to achieve diffraction limited imaging performance. The technique requires cameras capable of reading out frames at a very fast rate, effectively 'freezing out' atmospheric seeing. The resulting speckles can be correlated and images reconstructed that are at the diffraction limit of the telescope. These new instruments are based on the successful performance and design of the Differential Speckle Survey Instrument (DSSI).The instruments are being built for the Gemini-N and WIYN telescopes and will be made available to the community via the peer review proposal process. We envision their primary use to be validation and characterization of exoplanet targets from the NASA, K2 and TESS missions and RV discovered exoplanets. Such targets will provide excellent follow-up candidates for both the WIYN and Gemini telescopes. We expect similar data quality in speckle imaging mode with the new instruments. Additionally, both cameras will have a wide-field mode and standard SDSS filters. They will be highly versatile instruments and it is that likely many other science programs will request time on the cameras. The limiting magnitude for speckle observations will remain around 13-14th at WIYN and 16-17th at Gemini, while wide-field, normal CCD imaging operation should be able to go to much fainter, providing usual CCD imaging and photometric capabilities. The instruments will also have high utility as scoring cameras for telescope engineering purposes, or other applications where high time resolution is needed. Instrument support will be provided, including a software pipeline that takes raw speckle data to fully reconstructed images.

  17. A New Method for Wide-field Near-IR Imaging with the Hubble Space Telescope

    NASA Astrophysics Data System (ADS)

    Momcheva, Ivelina G.; van Dokkum, Pieter G.; van der Wel, Arjen; Brammer, Gabriel B.; MacKenty, John; Nelson, Erica J.; Leja, Joel; Muzzin, Adam; Franx, Marijn

    2017-01-01

    We present a new technique for wide and shallow observations using the near-infrared channel of Wide Field Camera 3 (WFC3) on the Hubble Space Telescope (HST). Wide-field near-IR surveys with HST are generally inefficient, as guide star acquisitions make it impractical to observe more than one pointing per orbit. This limitation can be circumvented by guiding with gyros alone, which is possible as long as the telescope has three functional gyros. The method presented here allows us to observe mosaics of eight independent WFC3-IR pointings in a single orbit by utilizing the fact that HST drifts by only a very small amount in the 25 s between non-destructive reads of unguided exposures. By shifting the reads and treating them as independent exposures the full resolution of WFC3 can be restored. We use this “drift and shift” (DASH) method in the Cycle 23 COSMOS-DASH program, which will obtain 456 WFC3 H 160 pointings in 57 orbits, covering an area of 0.6 degree in the COSMOS field down to H 160 = 25. When completed, the program will more than triple the area of extra-galactic survey fields covered by near-IR imaging at HST resolution. We demonstrate the viability of the method with the first four orbits (32 pointings) of this program. We show that the resolution of the WFC3 camera is preserved, and that structural parameters of galaxies are consistent with those measured in guided observations.

  18. Flight performance of an advanced CZT imaging detector in a balloon-borne wide-field hard X-ray telescope—ProtoEXIST1

    NASA Astrophysics Data System (ADS)

    Hong, J.; Allen, B.; Grindlay, J.; Barthelemy, S.; Baker, R.; Garson, A.; Krawczynski, H.; Apple, J.; Cleveland, W. H.

    2011-10-01

    We successfully carried out the first high-altitude balloon flight of a wide-field hard X-ray coded-aperture telescope ProtoEXIST1, which was launched from the Columbia Scientific Balloon Facility at Ft. Sumner, New Mexico on October 9, 2009. ProtoEXIST1 is the first implementation of an advanced CdZnTe (CZT) imaging detector in our ongoing program to establish the technology required for next generation wide-field hard X-ray telescopes such as the High Energy Telescope (HET) in the Energetic X-ray Imaging Survey Telescope (EXIST). The CZT detector plane in ProtoEXIST1 consists of an 8×8 array of closely tiled 2 cm×2 cm×0.5 cm thick pixellated CZT crystals, each with 8×8 pixels, mounted on a set of readout electronics boards and covering a 256 cm2 active area with 2.5 mm pixels. A tungsten mask, mounted at 90 cm above the detector provides shadowgrams of X-ray sources in the 30-600 keV band for imaging, allowing a fully coded field of view of 9°×9° (and 19°×19° for 50% coding fraction) with an angular resolution of 20‧. In order to reduce the background radiation, the detector is surrounded by semi-graded (Pb/Sn/Cu) passive shields on the four sides all the way to the mask. On the back side, a 26 cm×26 cm×2 cm CsI(Na) active shield provides signals to tag charged particle induced events as well as ≳100keV background photons from below. The flight duration was only about 7.5 h due to strong winds (60 knots) at float altitude (38-39 km). Throughout the flight, the CZT detector performed excellently. The telescope observed Cyg X-1, a bright black hole binary system, for ˜1h at the end of the flight. Despite a few problems with the pointing and aspect systems that caused the telescope to track about 6.4° off the target, the analysis of the Cyg X-1 data revealed an X-ray source at 7.2σ in the 30-100 keV energy band at the expected location from the optical images taken by the onboard daytime star camera. The success of this first flight is very

  19. Ray tracing simulations for the wide-field x-ray telescope of the Einstein Probe mission based on Geant4 and XRTG4

    NASA Astrophysics Data System (ADS)

    Zhao, Donghua; Zhang, Chen; Yuan, Weimin; Willingale, Richard; Ling, Zhixing; Feng, Hua; Li, Hong; Ji, Jianfeng; Wang, Wenxin; Zhang, Shuangnan

    2014-07-01

    Einstein Probe (EP) is a proposed small scientific satellite dedicated to time-domain astrophysics working in the soft X-ray band. It will discover transients and monitor variable objects in 0.5-4 keV, for which it will employ a very large instantaneous field-of-view (60° × 60°), along with moderate spatial resolution (FWHM ˜ 5 arcmin). Its wide-field imaging capability will be achieved by using established technology in novel lobster-eye optics. In this paper, we present Monte-Carlo simulations for the focusing capabilities of EP's Wide-field X-ray Telescope (WXT). The simulations are performed using Geant4 with an X-ray tracer which was developed by cosine (http://cosine.nl/) to trace X-rays. Our work is the first step toward building a comprehensive model with which the design of the X-ray optics and the ultimate sensitivity of the instrument can be optimized by simulating the X-ray tracing and radiation environment of the system, including the focal plane detector and the shielding at the same time.

  20. Design of integration time for the space-borne multi-spectral imager with super-wide field of view based on freeform mirror

    NASA Astrophysics Data System (ADS)

    Yin, Huan; Zhu, Jun; Zhang, Yongchao; Lu, Chunling; Wang, Chao; Ge, Xianying

    2015-08-01

    The freeform optics is extensively applied in the fields of aerospace, aviation, lighting, medical treatment, et al.. For the linearly push-broom space-borne imager, integration time of different field of view can be affected by the optical system design of the imager, orbits of the satellite, maneuver of the attitudes, rotation of the Earth, light delay due to the refraction and transmission of the atmosphere, terrain error and so on. The dynamically imaging quality should be affected by the accuracy and adjusting mode of the integration time. In this paper, a new method which is especially appropriate to imaging model simulating and integration time calculating for the wide-field-of-view remote sensor is proposed. Then, the integration time of specified viewing direction for the imager with a single projection center and a super-wide field of view based on freeform mirror, which is mounted on a sun-synchronous orbit satellite, is calculated. And influence on imaging quality of adjusting integration time of different grouping modes for the focal plane assembly is analyzed. The results indicate that with the constraint condition of satellite roll angle and the modulation transfer function (MTF) influence factor no more than 20°and 2% respectively, integration time of all CCDs for the whole focal plane assembly divided into two groups with each adopting the uniform integration time, can fulfill the requirements of the imaging quality for the imager.

  1. Low coherence full field interference microscopy or optical coherence tomography: recent advances, limitations and future trends

    NASA Astrophysics Data System (ADS)

    Abdulhalim, I.

    2013-04-01

    Although low coherence microscopy (LCM) has been known for long time in the context of interference microscopy, coherence radar and white light interferometry, the whole subject has attracted a wide interest in the last two decades particularly accelerated by the entrance of OCT, as a noninvasive powerful technique for biomedical imaging. Today LCM can be classified into two types, both acts as three-dimensional imaging tool. The first is low temporal coherence microscopy; also known as optical coherence tomography (OCT), which is being used for medical diagnostics. The second is full field OCT in various modes and applied to various applications. FF-OCT uses low spatial and temporal coherence similar to the well-known coherence probe microscope (CPM) that have been in use for long time in optical metrology. The CPM has many advantages over conventional microscopy in its ability to discriminate between different transparent layers in a scattering medium thus allowing for precise noninvasive optical probing of dense tissue and other turbid media. In this paper the status of this technology in optical metrology applications will be discussed, on which we have been working to improve its performance, as well as its limitations and future prospective.

  2. Mid-infrared Variability from the Spitzer Deep Wide-field Survey

    NASA Astrophysics Data System (ADS)

    Kozłowski, Szymon; Kochanek, Christopher S.; Stern, Daniel; Ashby, Matthew L. N.; Assef, Roberto J.; Bock, J. J.; Borys, C.; Brand, K.; Brodwin, M.; Brown, M. J. I.; Cool, R.; Cooray, A.; Croft, S.; Dey, Arjun; Eisenhardt, P. R.; Gonzalez, A.; Gorjian, V.; Griffith, R.; Grogin, N.; Ivison, R.; Jacob, J.; Jannuzi, B. T.; Mainzer, A.; Moustakas, L.; Röttgering, H.; Seymour, N.; Smith, H. A.; Stanford, S. A.; Stauffer, J. R.; Sullivan, I. S.; van Breugel, W.; Willner, S. P.; Wright, E. L.

    2010-06-01

    We use the multi-epoch, mid-infrared Spitzer Deep Wide-Field Survey to investigate the variability of objects in 8.1 deg2 of the NOAO Deep Wide Field Survey Boötes field. We perform a Difference Image Analysis of the four available epochs between 2004 and 2008, focusing on the deeper 3.6 and 4.5 μm bands. Out of 474, 179 analyzed sources, 1.1% meet our standard variability selection criteria that the two light curves are strongly correlated (r>0.8) and that their joint variance (σ12) exceeds that for all sources with the same magnitude by 2σ. We then examine the mid-IR colors of the variable sources and match them with X-ray sources from the XBoötes survey, radio catalogs, 24 μm selected active galactic nucleus (AGN) candidates, and spectroscopically identified AGNs from the AGN and Galaxy Evolution Survey (AGES). Based on their mid-IR colors, most of the variable sources are AGNs (76%), with smaller contributions from stars (11%), galaxies (6%), and unclassified objects, although most of the stellar, galaxy, and unclassified sources are false positives. For our standard selection criteria, 11%-12% of the mid-IR counterparts to X-ray sources, 24 μm AGN candidates, and spectroscopically identified AGNs show variability. The exact fractions depend on both the search depth and the selection criteria. For example, 12% of the 1131 known z>1 AGNs in the field and 14%-17% of the known AGNs with well-measured fluxes in all four Infrared Array Camera bands meet our standard selection criteria. The mid-IR AGN variability can be well described by a single power-law structure function with an index of γ ≈ 0.5 at both 3.6 and 4.5 μm, and an amplitude of S 0 ~= 0.1 mag on rest-frame timescales of 2 yr. The variability amplitude is higher for shorter rest-frame wavelengths and lower luminosities.

  3. Wide field array calibration dependence on the stability of measured dose distributions

    SciTech Connect

    Simon, Thomas A.; Simon, William E.; Kahler, Darren; Li, Jonathan; Liu, Chihray

    2010-07-15

    Purpose: The aim of this work was to simulate the effect of dose distribution changes on detector array calibrations and to explore compensatory methods that are used during calibration measurements. Methods: The array calibration technique that was investigated is known as wide field (WF) calibration. Using this method, a linear array [y-axis (65 detectors) of the IC PROFILER (Sun Nuclear Corporation, Melbourne, FL)] is calibrated with three measurements ({alpha}, {theta}, and {lambda}); each measurement uses the same radiation field, which is larger than the array. For measurement configuration {theta}, the array is rotated by 180 deg. from its position in {alpha}; for {lambda}, the array is shifted by one detector from its position in {theta}. The relative detector sensitivities are then determined through ratios of detector readings at the same field locations (using {theta} and {lambda}). This method results in error propagation that is proportional to the number of detectors in the array. During the procedure, the calibration protocol operates under three postulates, which state that (a) the beam shape does not change between measurements; (b) the relative sensitivities of the detectors do not change; and (c) the scatter to the array does not change as the array is moved. The WF calibration's sensitivity to a postulate (a) violation was quantified by applying a sine shaped perturbation (of up to 0.1%) to {alpha}, {theta}, or {lambda}, and then determining the change relative to a baseline calibration. Postulate (a) violations were minimized by using a continuous beam and mechanized array movement during {theta} and {lambda}. A continuously on beam demonstrated more stable beam symmetry as compared to cycling the beam on and off between measurements. Additional side-scatter was also used to satisfy postulate (c). Results: Simulated symmetry perturbations of 0.1% to {theta} or {lambda} resulted in calibration errors of up to 2%; {alpha} was relatively immune to

  4. Simulation of optical response of retroreflectors for future lunar laser ranging

    NASA Astrophysics Data System (ADS)

    Otsubo, Toshimichi; Kunimori, Hiroo; Noda, Hirotomo; Hanada, Hideo

    2010-03-01

    We numerically examined various retroreflectors as laser ranging targets for future missions to the Moon. The geometric conditions, such as the angle of incidence and velocity aberration, with lunar targets are much more restricted than those with most of the earth-orbiting artificial satellites. The numerical optical response simulation carried out in this study indicates that a single retroreflector with a diameter of 150-250 mm performs similar to the existing Apollo retroreflector arrays. Further, no dihedral angle is required for small retroreflectors with diameters below 150 mm for uncoated ones and below 100 mm for coated and hollow ones. Retroreflectors with larger diameters require dihedral angles of 0.20, 0.25, and 0.35 arcsec for coated, uncoated and hollow types, respectively. The objective of this fundamental study is to underlie the development of future laser ranging targets that are to be placed on the Moon.

  5. Thermal Vacuum Test Performance of the Hubble Space Telescope (HST) Wide Field Camera 3 (WFC3) Variable Conductance Heat Pipe Assembly

    NASA Technical Reports Server (NTRS)

    Cleveland, Paul E.; Buchko, Matthew T.; Stavely, Richard A.

    2003-01-01

    The Variable Conductance Heat Pipe (VCHP) Assembly of the HST Wide Field Camera 3 was subjected to thermal vacuum (TN) environmental testing. The test program included both maximum and minimum environments as well as simulated on-orbit cycling. Elements of the VCHP assembly included a VCHP, an optical bench cold plate with an imbedded constant conductance heat pipe, and a VCHP reservoir radiator with a proportionally controlled heater. The purpose of the test was to characterize and demonstrate the assembly s ability to control the temperature of the cold plate, which provides a stable thermal environment for the instrument s optical bench. This paper discusses the VCHP Assembly control performance and control authority during the dynamic hot and cold 90-minute orbit cycling test phases.

  6. Futurism.

    ERIC Educational Resources Information Center

    Foy, Jane Loring

    The objectives of this research report are to gain insight into the main problems of the future and to ascertain the attitudes that the general population has toward the treatment of these problems. In the first section of this report the future is explored socially, psychologically, and environmentally. The second section describes the techniques…

  7. Optical characterisation and analysis of multi-mode pixels for use in future far infrared telescopes

    NASA Astrophysics Data System (ADS)

    McCarthy, Darragh; Trappe, Neil; Murphy, J. Anthony; Doherty, Stephen; Gradziel, Marcin; O'Sullivan, Créidhe; Audley, Michael D.; de Lange, Gert; van der Vorst, Maarten

    2016-07-01

    In this paper we present the development and verification of feed horn simulation code based on the mode- matching technique to simulate the electromagnetic performance of waveguide based structures of rectangular cross-section. This code is required to model multi-mode pyramidal horns which may be required for future far infrared (far IR) space missions where wavelengths in the range of 30 to 200 µm will be analysed. Multi-mode pyramidal horns can be used effectively to couple radiation to sensitive superconducting devices like Kinetic Inductance Detectors (KIDs) or Transition Edge Sensor (TES) detectors. These detectors could be placed in integrating cavities (to further increase the efficiency) with an absorbing layer used to couple to the radiation. The developed code is capable of modelling each of these elements, and so will allow full optical characterisation of such pixels and allow an optical efficiency to be calculated effectively. As the signals being measured at these short wavelengths are at an extremely low level, the throughput of the system must be maximised and so multi-mode systems are proposed. To this end, the focal planes of future far IR missions may consist of an array of multi-mode rectangular feed horns feeding an array of, for example, TES devices contained in individual integrating cavities. Such TES arrays have been fabricated by SRON Groningen and are currently undergoing comprehensive optical, electrical and thermal verification. In order to fully understand and validate the optical performance of the receiver system, it is necessary to develop comprehensive and robust optical models in parallel. We outline the development and verification of this optical modelling software by means of applying it to a representative multi-mode system operating at 150 GHz in order to obtain sufficiently short execution times so as to comprehensively test the code. SAFARI (SPICA FAR infrared Instrument) is a far infrared imaging grating spectrometer

  8. Calibration of a wide-field frequency-domain fluorescence lifetime microscopy system using light emitting diodes as light sources.

    PubMed

    Elder, A D; Frank, J H; Swartling, J; Dai, X; Kaminski, C F

    2006-11-01

    High brightness light emitting diodes are an inexpensive and versatile light source for wide-field frequency-domain fluorescence lifetime imaging microscopy. In this paper a full calibration of an LED based fluorescence lifetime imaging microscopy system is presented for the first time. A radio-frequency generator was used for simultaneous modulation of light emitting diode (LED) intensity and the gain of an intensified charge coupled device (CCD) camera. A homodyne detection scheme was employed to measure the demodulation and phase shift of the emitted fluorescence, from which phase and modulation lifetimes were determined at each image pixel. The system was characterized both in terms of its sensitivity to measure short lifetimes (500 ps to 4 ns), and its capability to distinguish image features with small lifetime differences. Calibration measurements were performed in quenched solutions containing Rhodamine 6G dye and the results compared to several independent measurements performed with other measurement methodologies, including time correlated single photon counting, time gated detection, and acousto optical modulator (AOM) based modulation of excitation sources. Results are presented from measurements and simulations. The effects of limited signal-to-noise ratios, baseline drifts and calibration errors are discussed in detail. The implications of limited modulation bandwidth of high brightness, large area LED devices ( approximately 40 MHz for devices used here) are presented. The results show that phase lifetime measurements are robust down to sub ns levels, whereas modulation lifetimes are prone to errors even at large signal-to-noise ratios. Strategies for optimizing measurement fidelity are discussed. Application of the fluorescence lifetime imaging microscopy system is illustrated with examples from studies of molecular mixing in microfluidic devices and targeted drug delivery research.

  9. Near-infrared Emission Spectrum of WASP-103b Using Hubble Space Telescope/Wide Field Camera 3

    NASA Astrophysics Data System (ADS)

    Cartier, Kimberly M. S.; Beatty, Thomas G.; Zhao, Ming; Line, Michael; Ngo, Henry; Mawet, Dimitri; Stassun, Keivan G.; Wright, Jason T.; Kreidberg, Laura; Fortney, Jonathan; Knutson, Heather

    2017-01-01

    We present here our observations and analysis of the dayside emission spectrum of the hot Jupiter WASP-103b. We observed WASP-103b during secondary eclipse using two visits of the Hubble Space Telescope with the G141 grism on Wide Field Camera 3 in spatial scan mode. We generated secondary eclipse light curves of the planet in both blended white-light and spectrally binned wavechannels from 1.1 {to} 1.7 μ {{m}} and corrected the light curves for flux contamination from a nearby companion star. We modeled the detector systematics and secondary eclipse spectrum using Gaussian process regression and found that the near-IR emission spectrum of WASP-103b is featureless across the observed near-IR region to down to a sensitivity of 175 ppm, and shows a shallow slope toward the red. The atmosphere has a single brightness temperature of {T}{{B}}=2890 K across this wavelength range. This region of the spectrum is indistinguishable from isothermal, but may not manifest from a physically isothermal system, i.e., pseudo-isothermal. A solar-metallicity profile with a thermal inversion layer at 10‑2 bar fits the spectrum of WASP-103b with high confidence, as do an isothermal profile with solar metallicity and a monotonically decreasing atmosphere with C/O > 1. The data rule out a monotonically decreasing atmospheric profile with solar composition, and we rule out a low-metallicity decreasing profile as unphysical for this system. The pseudo-isothermal profile could be explained by a thermal inversion layer just above the layer probed by our observations, or by clouds or haze in the upper atmosphere. Transmission spectra at optical wavelengths would allow us to better distinguish between potential atmospheric models. Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by AURA, Inc., under NASA contract NAS 5-26555.

  10. An accurate cluster selection function for the J-PAS narrow-band wide-field survey

    NASA Astrophysics Data System (ADS)

    Ascaso, B.; Benítez, N.; Dupke, R.; Cypriano, E.; Lima-Neto, G.; López-Sanjuan, C.; Varela, J.; Alcaniz, J. S.; Broadhurst, T.; Cenarro, A. J.; Devi, N. Chandrachani; Díaz-García, L. A.; Fernandes, C. A. C.; Hernández-Monteagudo, C.; Mei, S.; Mendes de Oliveira, C.; Molino, A.; Oteo, I.; Schoenell, W.; Sodré, L.; Viironen, K.; Marín-Franch, A.

    2016-03-01

    The impending Javalambre Physics of the accelerating Universe Astrophysical Survey (J-PAS) will be the first wide-field survey of ≳ 8500 deg2 to reach the `stage IV' category. Because of the redshift resolution afforded by 54 narrow-band filters, J-PAS is particularly suitable for cluster detection in the range z<1. The photometric redshift dispersion is estimated to be only ˜0.003 with few outliers ≲4 per cent for galaxies brighter than i ˜ 23 AB, because of the sensitivity of narrow band imaging to absorption and emission lines. Here, we evaluate the cluster selection function for J-PAS using N-body+semi-analytical realistic mock catalogues. We optimally detect clusters from this simulation with the Bayesian Cluster Finder, and we assess the completeness and purity of cluster detection against the mock data. The minimum halo mass threshold we find for detections of galaxy clusters and groups with both >80 per cent completeness and purity is Mh ˜ 5 × 1013 M⊙ up to z ˜ 0.7. We also model the optical observable, M^{*}_CL-halo mass relation, finding a non-evolution with redshift and main scatter of σ _{M^{*}_CL | M_h}˜ 0.14 dex down to a factor 2 lower in mass than other planned broad-band stage IV surveys, at least. For the Mh ˜ 1 × 1014 M⊙ Planck mass limit, J-PAS will arrive up to z ˜ 0.85 with a σ _{M^{*}_CL | M_h}˜ 0.12 dex. Therefore, J-PAS will provide the largest sample of clusters and groups up to z ˜ 0.8 with a mass calibration accuracy comparable to X-ray data.

  11. The on-chip guiding system of the wide-field infrared camera at CFHT

    NASA Astrophysics Data System (ADS)

    Albert, Loic; Riopel, Martin; Teeple, Douglas; Ward, Jeff; Barrick, Greg

    2005-08-01

    The Canada-France-Hawaii Telescope (CFHT) is commissioning a new Wide field Infrared Camera (WIRCam) that uses a mosaic of 4 HAWAII-2RG near-infrared detectors manufactured by Rockwell. At the heart of the instrument is an On-Chip Guiding System (OCGS) that exploits the unique parallel science/guide frame readout capability of the HAWAII-2RG detectors. A small subsample of each array is continuously read at a rate of 50 Hz while the integration of the science image is ongoing with the full arrays. Each of these guiding windows is centered on a star to provide an error signal for the telescope guiding. An Image Stabilizer Unit (ISU) (i.e. a tip-tilt silica plate), provides the corrections. A Proportional Integral Differential (PID) closed loop controls the ISU such that telescope tracking is corrected at a rate of 5 Hz. The guide window size and readout rate are adjustable but typical numbers are 8×8-16×16 boxes read at 50 or 1.5 Hz. This paper presents the technical architecture of the guiding system and performance measurements on the sky with WIRCam.

  12. Brief wide-field photostimuli evoke and modulate oscillatory reverberating activity in cortical networks

    PubMed Central

    Pulizzi, Rocco; Musumeci, Gabriele; Van den Haute, Chris; Van De Vijver, Sebastiaan; Baekelandt, Veerle; Giugliano, Michele

    2016-01-01

    Cell assemblies manipulation by optogenetics is pivotal to advance neuroscience and neuroengineering. In in vivo applications, photostimulation often broadly addresses a population of cells simultaneously, leading to feed-forward and to reverberating responses in recurrent microcircuits. The former arise from direct activation of targets downstream, and are straightforward to interpret. The latter are consequence of feedback connectivity and may reflect a variety of time-scales and complex dynamical properties. We investigated wide-field photostimulation in cortical networks in vitro, employing substrate-integrated microelectrode arrays and long-term cultured neuronal networks. We characterized the effect of brief light pulses, while restricting the expression of channelrhodopsin to principal neurons. We evoked robust reverberating responses, oscillating in the physiological gamma frequency range, and found that such a frequency could be reliably manipulated varying the light pulse duration, not its intensity. By pharmacology, mathematical modelling, and intracellular recordings, we conclude that gamma oscillations likely emerge as in vivo from the excitatory-inhibitory interplay and that, unexpectedly, the light stimuli transiently facilitate excitatory synaptic transmission. Of relevance for in vitro models of (dys)functional cortical microcircuitry and in vivo manipulations of cell assemblies, we give for the first time evidence of network-level consequences of the alteration of synaptic physiology by optogenetics. PMID:27099182

  13. Exoplanets from the Arctic: The First Wide-field Survey at 80°N

    NASA Astrophysics Data System (ADS)

    Law, Nicholas M.; Carlberg, Raymond; Salbi, Pegah; Ngan, Wai-Hin Wayne; Ahmadi, Aida; Steinbring, Eric; Murowinski, Richard; Sivanandam, Suresh; Kerzendorf, Wolfgang

    2013-03-01

    Located within 10° of the North Pole, northern Ellesmere Island offers continuous darkness in the winter months. This capability can greatly enhance the detection efficiency of planetary transit surveys and other time domain astronomy programs. We deployed two wide-field cameras at 80°N, near Eureka, Nunavut, for a 152 hr observing campaign in 2012 February. The 16 megapixel camera systems were based on commercial f/1.2 lenses with 70 mm and 42 mm apertures, and they continuously imaged 504 and 1295 deg2, respectively. In total, the cameras took over 44,000 images and produced better than 1% precision light curves for approximately 10,000 stars. We describe a new high-speed astrometric and photometric data reduction pipeline designed for the systems, test several methods for the precision flat fielding of images from very-wide-angle cameras, and evaluate the cameras' image qualities. We achieved a scintillation-limited photometric precision of 1%-2% in each 10 s exposure. Binning the short exposures into 10 minute chunks provided a photometric stability of 2-3 mmag, sufficient for the detection of transiting exoplanets around the bright stars targeted by our survey. We estimate that the cameras, when operated over the full Arctic winter, will be capable of discovering several transiting exoplanets around bright (mV < 9.5) stars.

  14. Clinically compatible flexible wide-field multi-color fluorescence endoscopy with a porcine colon model

    PubMed Central

    Oh, Gyugnseok; Park, Youngrong; Yoo, Su Woong; Hwang, Soonjoo; Chin-Yu, Alexey V. Dan; Ryu, Yeon-Mi; Kim, Sang-Yeob; Do, Eun-Ju; Kim, Ki Hean; Kim, Sungjee; Myung, Seung-Jae; Chung, Euiheon

    2017-01-01

    Early detection of structural or molecular changes in dysplastic epithelial tissues is crucial for cancer screening and surveillance. Multi-targeting molecular endoscopic fluorescence imaging may improve noninvasive detection of precancerous lesions in the colon. Here, we report the first clinically compatible, wide-field-of-view, multi-color fluorescence endoscopy with a leached fiber bundle scope using a porcine model. A porcine colon model that resembles the human colon is used for the detection of surrogate tumors composed of multiple biocompatible fluorophores (FITC, ICG, and heavy metal-free quantum dots (hfQDs)). With an ex vivo porcine colon tumor model, molecular imaging with hfQDs conjugated with MMP14 antibody was achieved by spraying molecular probes on a mucosa layer that contains xenograft tumors. With an in vivo porcine colon embedded with surrogate tumors, target-to-background ratios of 3.36 ± 0.43, 2.70 ± 0.72, and 2.10 ± 0.13 were achieved for FITC, ICG, and hfQD probes, respectively. This promising endoscopic technology with molecular contrast shows the capacity to reveal hidden tumors and guide treatment strategy decisions. PMID:28270983

  15. (Sn)DICE: A Calibration System Designed for Wide Field Imagers

    NASA Astrophysics Data System (ADS)

    Regnault, N.; Barrelet, E.; Guyonnet, A.; Juramy, C.; Rocci, P.-F.; Le Guillou, L.; Schahmanèche, K.; Villa, F.

    2016-05-01

    Dark Energy studies with type Ia supernovae set very tight constraints on the photometric calibration of the imagers used to detect the supernovae and follow up their flux variations. Among the key challenges is the measurement of the shape and normalization of the instrumental throughput. The DICE system was developed by members of the Supernova Legacy Survey (SNLS) , building upon the lessons learnt working with the MegaCam imager. It consists in a very stable light source, placed in the telescope enclosure, and generating compact, conical beams, yielding an almost flat illumination of the imager focal plane. The calibration light is generated by narrow spectrum LEDs selected to cover the entire wavelength range of the imager. It is monitored in real time using control photodiodes. A first DICE demonstrator, SnDICE has been installed at CFHT. A second generation instrument (SkyDICE) has been installed in the enclosure of the SkyMapper telescope. We present the main goals of the project. We discuss the main difficulties encoutered when trying to calibrate a wide field imager, such as MegaCam (or SkyMapper) using such a calibrated light source.

  16. Wide-field computational color imaging using pixel super-resolved on-chip microscopy

    PubMed Central

    Greenbaum, Alon; Feizi, Alborz; Akbari, Najva; Ozcan, Aydogan

    2013-01-01

    Lens-free holographic on-chip imaging is an emerging approach that offers both wide field-of-view (FOV) and high spatial resolution in a cost-effective and compact design using source shifting based pixel super-resolution. However, color imaging has remained relatively immature for lens-free on-chip imaging, since a ‘rainbow’ like color artifact appears in reconstructed holographic images. To provide a solution for pixel super-resolved color imaging on a chip, here we introduce and compare the performances of two computational methods based on (1) YUV color space averaging, and (2) Dijkstra’s shortest path, both of which eliminate color artifacts in reconstructed images, without compromising the spatial resolution or the wide FOV of lens-free on-chip microscopes. To demonstrate the potential of this lens-free color microscope we imaged stained Papanicolaou (Pap) smears over a wide FOV of ~14 mm2 with sub-micron spatial resolution. PMID:23736466

  17. The Wide-Field Infrared Survey Explorer (WISE): Mission Description and Initial On-Orbit Performance

    NASA Technical Reports Server (NTRS)

    Wright, Edward L.; Eisenhardt, Peter R. M.; Mainzer, Amy; Ressler, Michael E.; Cutri, Roc M.; Jarrett, Thomas; Kirkpatrick, J. Davy; Padgett, Deborah; McMillan, Robert S.; Skrutskie,Michael; Stanford, S. A.; Cohen, Martin; Walker, Russell G.; Mather, John C.; Leisawitz, David; Gautier, Thomas N., III; McLean, Ian; Benford, Dominic; Lonsdale,Carol J.; Blain, Andrew; Mendez,Bryan; Irace, William R.; Duval, Valerie; Liu, Fengchuan; Royer, Don

    2010-01-01

    The all sky surveys done by the Palomar Observatory Schmidt, the European Southern Observatory Schmidt, and the United Kingdom Schmidt, the InfraRed Astronomical Satellite and the 2 Micron All Sky Survey have proven to be extremely useful tools for astronomy with value that lasts for decades. The Wide-field Infrared Survey Explorer is mapping the whole sky following its launch on 14 December 2009. WISE began surveying the sky on 14 Jan 2010 and completed its first full coverage of the sky on July 17. The survey will continue to cover the sky a second time until the cryogen is exhausted (anticipated in November 2010). WISE is achieving 5 sigma point source sensitivities better than 0.08, 0.11, 1 and 6 mJy in unconfused regions on the ecliptic in bands centered at wavelengths of 3.4, 4.6, 12 and 22 micrometers. Sensitivity improves toward the ecliptic poles due to denser coverage and lower zodiacal background. The angular resolution is 6.1", 6.4", 6.5" and 12.0" at 3.4, 4.6, 12 and 22 micrometers, and the astrometric precision for high SNR sources is better than 0.15".

  18. Ground characterization of the Wide-field Infrared Explorer (WIRE) instrument

    NASA Astrophysics Data System (ADS)

    Kemp, John C.; Larsen, Mark F.; Peterson, James Q.; Sargent, Steven D.

    1998-11-01

    The Wide-Field Infrared Explorer (WIRE) is a small cryogenic spaceborne infrared telescope being readied for launch in September 1998 as the fifth of NASA's Small Explorers. WIRE utilizes two 128 X 128 Si:As Focal Plane Arrays (FPAs) produced by Boeing North American with a 30 cm diameter Ritchey Cretien diamond turned mirror system. This mission takes advantage of recent advances in infrared array detector technology to provide a large sensitivity gain over previously flown missions. Two broad pass bands are defined for a deep pointed survey to search for protogalaxies and to study the evolution of starburst galaxies. The Space Dynamics Laboratory at Utah State University (SDL/USU) used the multifunction infrared calibrator and other special purpose cryogenic equipment to perform a ground characterization of the WIRE instrument. The focus was verified cold with two independent measurements. Both in-band and out-of-band Relative Spectral Response measurements were made; some sensitivity to temperature, bias voltage, and location on the long wavelength focal plane array were found. Dark current and dark noise measurements are also reported.

  19. Intraoperative detection and removal of microscopic residual sarcoma using wide-field imaging

    PubMed Central

    Mito, Jeffrey K; Ferrer, Jorge M; Brigman, Brian E; Lee, Chang-Lung; Dodd, Rebecca D; Eward, William C; Marshall, Lisa F; Cuneo, Kyle C; Carter, Jessica E; Ramasunder, Shalini; Kim, Yongbaek; Lee, W David; Griffith, Linda G; Bawendi, Moungi G; Kirsch, David G

    2012-01-01

    Abstract BACKGROUND: The goal of limb-sparing surgery for a soft tissue sarcoma of the extremity is to remove all malignant cells while preserving limb function. After initial surgery, microscopic residual disease in the tumor bed will cause a local recurrence in approximately 33% of patients with sarcoma. To help identify these patients, the authors developed an in vivo imaging system to investigate the suitability of molecular imaging for intraoperative visualization. METHODS: A primary mouse model of soft tissue sarcoma and a wide field-of-view imaging device were used to investigate a series of exogenously administered, near-infrared (NIR) fluorescent probes activated by cathepsin proteases for real-time intraoperative imaging. RESULTS: The authors demonstrated that exogenously administered cathepsin-activated probes can be used for image-guided surgery to identify microscopic residual NIR fluorescence in the tumor beds of mice. The presence of residual NIR fluorescence was correlated with microscopic residual sarcoma and local recurrence. The removal of residual NIR fluorescence improved local control. CONCLUSIONS: The authors concluded that their technique has the potential to be used for intraoperative image-guided surgery to identify microscopic residual disease in patients with cancer. Cancer 2012. © 2012 American Cancer Society. PMID:22437667

  20. Wide-field SCUBA-2 observations of NGC 2264: submillimetre clumps and filaments

    NASA Astrophysics Data System (ADS)

    Buckle, J. V.; Richer, J. S.

    2015-10-01

    We present wide-field observations of the NGC 2264 molecular cloud in the dust continuum at 850 and 450 μm using SCUBA-2 on the James Clerk Maxwell Telescope. Using 12CO 3 → 2 molecular line data, we determine that emission from CO contaminates the 850 μm emission at levels ˜30 per cent in localized regions associated with high-velocity molecular outflows. Much higher contamination levels of 60 per cent are seen in shocked regions near the massive star S Mon. If not removed, the levels of CO contamination would contribute an extra 13 per cent to the dust mass in NGC 2264. We use the FELLWALKER routine to decompose the dust into clumpy structures, and a Hessian-based routine to decompose the dust into filamentary structures. The filaments can be described as a hub-filament structure, with lower column density filaments radiating from the NGC 2264 C protocluster hub. Above mean filament column densities of 2.4 × 1022 cm-2, star formation proceeds with the formation of two or more protostars. Below these column densities, filaments are starless, or contain only a single protostar.

  1. Automatic vessel segmentation in wide-field retina images of infants with retinopathy of prematurity.

    PubMed

    Poletti, Enea; Fiorin, Diego; Grisan, Enrico; Ruggeri, Alfredo

    2011-01-01

    The earliest signs of Retinopathy of Prematurity (ROP) are tortuosity and dilation of retinal vessels. Such vascular changes are considered of primary importance for the diagnosis and the follow-up of the disease. However, a widely accepted computerized system for their quantitative measurement is still missing. Images taken from a preterm baby's eye are often low-contrast, noisy, and blurred. Algorithms that have been successfully applied to analyze adult retinal images do not work well in ROP images. We propose here a novel method for the automatic extraction of vessel centerline in wide-field ROP retinal images, based on a sparse tracking scheme. After a set of seed points is identified all over the image, vessels are traced by connecting those seeds by means of minimum cost paths, whose weights depend on similarity features and alignment evaluated by a custom line operator. The performance of the method was assessed on a dataset of 20 images acquired with the RetCam fundus camera. A sensitivity of 0.78 and a false detection rate of 0.15 were obtained with respect to manual ground truth reference.

  2. Narrow and wide field amacrine cells fire action potentials in response to depolarization and light stimulation.

    PubMed

    Heflin, Stephanie J; Cook, Paul B

    2007-01-01

    Action potentials in amacrine cells are important for lateral propagation of signals across the inner retina, but it is unclear how many subclasses of amacrine cells contain voltage-gated sodium channels or can fire action potentials. This study investigated the ability of amacrine cells with narrow ( <200 microm) and wide (>200 microm) dendritic fields to fire action potentials in response to depolarizing current injections and light stimulation. The pattern of action potentials evoked by current injections revealed two distinct classes of amacrine cells; those that responded with a single action potential (single-spiking cells) and those that responded with repetitive action potentials (repetitive-spiking cells). Repetitive-spiking cells differed from single-spiking cells in several regards: Repetitive-spiking cells were more often wide field cells, while single-spiking cells were more often narrow field cells. Repetitive-spiking cells had larger action potential amplitudes, larger peak voltage-gated NaV currents lower action potential thresholds, and needed less current to induce action potentials. However, there was no difference in the input resistance, holding current or time constant of these two classes of cells. The intrinsic capacity to fire action potentials was mirrored in responses to light stimulation; single-spiking amacrine cells infrequently fired action potentials to light steps, while repetitive-spiking amacrine cells frequently fired numerous action potentials. These results indicate that there are two physiologically distinct classes of amacrine cells based on the intrinsic capacity to fire action potentials.

  3. The Kepler Mission: A wide-field transit search for terrestrial planets [review article

    NASA Astrophysics Data System (ADS)

    Basri, Gibor; Borucki, William J.; Koch, David

    2005-11-01

    The Kepler Mission is a NASA Discovery mission which will continuously monitor the brightness of at least 100,000 main sequence stars, to detect the transits of terrestrial and larger planets. It is scheduled to be launched in 2007 into an Earth-trailing heliocentric orbit. It is a wide-field photometer with a Schmidt-type telescope and array of 42 CCDs covering the 100 square degree field-of-view. It has a 1-m aperture which enables a differential photometric precision of 2 parts in 100,000 for 12th magnitude solar-like stars over a 6.5-hour transit duration. It will continuously observe dwarf stars from 8th to 15th magnitude in the Cygnus constellation, for a period of four years, with a cadence of 4 measurements per hour. Hundreds of terrestrial planets should be detected if they are common around solar-type stars. Ground-based spectrometry of stars with planetary candidates will help eliminate false-positives, and determine stellar characteristics such as mass and metallicity. A null result would imply that terrestrial planets are rare.

  4. Wide Field Collimator 2 (WFC2) for GOES Imager and Sounder

    NASA Technical Reports Server (NTRS)

    Etemad, Shahriar; Bremer, James C.; Zukowski, Barbara J.; Pasquale, Bert A.; zukowski, Tmitri J.; Prince, Robert E.; O'Neill, Patrick A.; Ross, Robert W.

    2004-01-01

    Two of the GOES instruments, the Imager and the Sounder, perform scans of the Earth to provide a full disc picture of the Earth. To verify the entire scan process, an image of a target that covers an 18 deg. circular field-of-view is collimated and projected into the field of regard of each instrument. The Wide Field Collimator 2 (WFC2) has many advantages over its predecessor, WFC1, including lower thermal dissipation higher fir field MTF, smaller package, and a more intuitive (faster) focusing process. The illumination source is an LED array that emits in a narrow spectral band centered at 689 nm, within the visible spectral bands of the Imager and Sounder. The illumination level can be continuously adjusted electronically. Lower thermal dissipation eliminates the need for forced convection cooling and minimizes time to reach thermal stability. The lens system has been optimized for the illumination source spectral output and athernalized to remain in focus during bulk temperature changes within the laboratory environment. The MTF of the lens is higher than that of the WFC1 at the edge of FOV. The target is focused in three orthogonal motions, controlled by an ergonomic system that saves substantial time and produces a sharper focus. Key words: Collimator, GOES, Imager, Sounder, Projector

  5. EXOPLANETS FROM THE ARCTIC: THE FIRST WIDE-FIELD SURVEY AT 80 Degree-Sign N

    SciTech Connect

    Law, Nicholas M.; Sivanandam, Suresh; Carlberg, Raymond; Salbi, Pegah; Ngan, Wai-Hin Wayne; Kerzendorf, Wolfgang; Ahmadi, Aida; Steinbring, Eric; Murowinski, Richard

    2013-03-15

    Located within 10 Degree-Sign of the North Pole, northern Ellesmere Island offers continuous darkness in the winter months. This capability can greatly enhance the detection efficiency of planetary transit surveys and other time domain astronomy programs. We deployed two wide-field cameras at 80 Degree-Sign N, near Eureka, Nunavut, for a 152 hr observing campaign in 2012 February. The 16 megapixel camera systems were based on commercial f/1.2 lenses with 70 mm and 42 mm apertures, and they continuously imaged 504 and 1295 deg{sup 2}, respectively. In total, the cameras took over 44,000 images and produced better than 1% precision light curves for approximately 10,000 stars. We describe a new high-speed astrometric and photometric data reduction pipeline designed for the systems, test several methods for the precision flat fielding of images from very-wide-angle cameras, and evaluate the cameras' image qualities. We achieved a scintillation-limited photometric precision of 1%-2% in each 10 s exposure. Binning the short exposures into 10 minute chunks provided a photometric stability of 2-3 mmag, sufficient for the detection of transiting exoplanets around the bright stars targeted by our survey. We estimate that the cameras, when operated over the full Arctic winter, will be capable of discovering several transiting exoplanets around bright (m{sub V} < 9.5) stars.

  6. Pulsed light imaging for wide-field dosimetry of photodynamic therapy in the skin

    NASA Astrophysics Data System (ADS)

    Davis, Scott C.; Sexton, Kristian; Chapman, Michael Shane; Maytin, Edward; Hasan, Tayyaba; Pogue, Brian W.

    2014-03-01

    Photodynamic therapy using aminoluvelinic acid (ALA) is an FDA-approved treatment for actinic keratoses, pre-cancerous skin lesions which pose a significant risk for immunocompromised individuals, such as organ transplant recipients. While PDT is generally effective, response rates vary, largely due to variations in the accumulation of the photosensitizer protoporphyrin IX (PpIX) after ALA application. The ability to quantify PpIX production before treatment could facilitate the use of additional interventions to improve outcomes. While many groups have demonstrated the ability to image PpIX in the clinic, these systems generally require darkening the room lights during imaging, which is unpopular with clinicians. We have developed a novel wide-field imaging system based on pulsed excitation and gated acquisition to image photosensitizer activity in the skin. The tissue is illuminated using four pulsed LED's to excite PpIX, and the remitted light acquired with a synchronized ICCD. This approach facilitates real-time background subtraction of ambient light, precluding the need to darken the exam room. Delivering light in short bursts also allows the use of elevated excitation intensity while remaining under the maximum permissible exposure limits, making the modality more sensitive to photosensitizer fluorescence than standard approaches. Images of tissue phantoms indicate system sensitivity down to 250nM PpIX and images of animals demonstrate detection of PpIX fluorescence in vivo under normal room light conditions.

  7. Flatfielding and photometric accuracy of the first Hubble Space Telescope Wide Field Camera

    NASA Technical Reports Server (NTRS)

    Phillips, Andrew C.; Forbes, Duncan A.; Bershady, Matthew A.; Illingworth, Garth D.; Koo, David C.

    1994-01-01

    Long exposures with the original Hubble Space Telescope (HST) Wide Field Camera (WFC) through the F555W and F785LP filters show gradients in the background following standard pipeline calibration. We show that these gradients also appear in stellar photometry, and thus must be predominantly the result of inaccurate flatfielding at a level of 10 to 20%. Color errors may be even larger. Applying corrections to the flatfield frames based on the background structure leads to an improved accuracy of approximately 4% for single-measurement photometry within a single CCD chip, compared to the approximately 10% accuracy suggested by previous studies. We have reanalyzed the F555W and F785LP calibration photometry to derive zero points appropriate for corrected data; these new zero points have internal consistency at a level of approximately 1.2%, based on comparison between the chip-to-chip offsets and the sky levels observed in corrected images. This indicates that relative photometry approaching 1 to 2% is achievable with the WFC. The new zero point values for corrected data are 22.90, 23.04, 23.04, and 22.96 (F555W), and 21.56, 21.64, 21.44, and 21.47 (F785LP) for chips WF1-WF4, respectively. Comparison is made with other zero points, and the applicability of 'delta flats' is briefly discussed.

  8. Wide-field wide-band Interferometric Imaging: The WB A-Projection and Hybrid Algorithms

    NASA Astrophysics Data System (ADS)

    Bhatnagar, S.; Rau, U.; Golap, K.

    2013-06-01

    Variations of the antenna primary beam (PB) pattern as a function of time, frequency, and polarization form one of the dominant direction-dependent effects at most radio frequency bands. These gains may also vary from antenna to antenna. The A-Projection algorithm, published earlier, accounts for the effects of the narrow-band antenna PB in full polarization. In this paper, we present the wide-band A-Projection algorithm (WB A-Projection) to include the effects of wide bandwidth in the A-term itself and show that the resulting algorithm simultaneously corrects for the time, frequency, and polarization dependence of the PB. We discuss the combination of the WB A-Projection and the multi-term multi-frequency synthesis (MT-MFS) algorithm for simultaneous mapping of the sky brightness distribution and the spectral index distribution across a wide field of view. We also discuss the use of the narrow-band A-Projection algorithm in hybrid imaging schemes that account for the frequency dependence of the PB in the image domain.

  9. Wide Field Camera 3 Instrument Handbook for Cycle 21 v. 5.0

    NASA Astrophysics Data System (ADS)

    Dressel, L.

    2012-12-01

    The Wide Field Camera 3 (WFC3) is a fourth-generation imaging instrument. It was installed in the Hubble Space Telescope (HST) during Servicing Mission 4 (SM4) in May 2009. WFC3 saw first light on June 24, 2009, following the cooling of its detectors. Servicing Mission 4 Observatory Verification (SMOV) activities were completed in late August 2009, and were followed by the Cycle 17 calibration and science programs. This WFC3 Instrument Handbook has been prepared by the WFC3 team at STScI. It is the basic technical reference manual for WFC3 observers. The information in this Handbook is intended to be useful for Cycle 21 Phase I proposers, for the subsequently selected General Observers (GOs) as they prepare their Phase II specifications, and for those analyzing WFC3 data. The HST Primer and the HST Call for Proposals also contain valuable information for proposers, and the Call for Proposals is the final authority on HST policy. This edition of the WFC3 Instrument Handbook (Version 5.0) was written near the end of the execution of the Cycle 19 calibration plan. It supersedes Version 4.0, and includes results from analysis of the first three cycles of on-orbit performance.

  10. WIDE-FIELD INFRARED SURVEY EXPLORER OBSERVATIONS OF THE EVOLUTION OF MASSIVE STAR-FORMING REGIONS

    SciTech Connect

    Koenig, X. P.; Leisawitz, D. T.; Benford, D. J.; Padgett, D. L.; Rebull, L. M.

    2012-01-10

    We present the results of a mid-infrared survey of 11 outer Galaxy massive star-forming regions and 3 open clusters with data from the Wide-field Infrared Survey Explorer (WISE). Using a newly developed photometric scheme to identify young stellar objects and exclude extragalactic contamination, we have studied the distribution of young stars within each region. These data tend to support the hypothesis that latter generations may be triggered by the interaction of winds and radiation from the first burst of massive star formation with the molecular cloud material leftover from that earlier generation of stars. We dub this process the 'fireworks hypothesis' since star formation by this mechanism would proceed rapidly and resemble a burst of fireworks. We have also analyzed small cutout WISE images of the structures around the edges of these massive star-forming regions. We observe large (1-3 pc size) pillar and trunk-like structures of diffuse emission nebulosity tracing excited polycyclic aromatic hydrocarbon molecules and small dust grains at the perimeter of the massive star-forming regions. These structures contain small clusters of emerging Class I and Class II sources, but some are forming only a single to a few new stars.

  11. Wide-Field Infrared Survey Explorer Observations of the Evolution of Massive Star-Forming Regions

    NASA Technical Reports Server (NTRS)

    Koenig, X. P.; Leisawitz, D. T.; Benford, D. J.; Rebull, L. M.; Padgett, D. L.; Asslef, R. J.

    2012-01-01

    We present the results of a mid-infrared survey of II outer Galaxy massive star-forming regions and 3 open clusters with data from the Wide-field Infrared Survey Explorer (WISE). Using a newly developed photometric scheme to identify young stellar objects and exclude extragalactic contamination, we have studied the distribution of young stars within each region. These data tend to support the hypothesis that latter generations may be triggered by the interaction of winds and radiation from the first burst of massive star formation with the molecular cloud material leftover from that earlier generation of stars. We dub this process the "fireworks hypothesis" since star formation by this mechanism would proceed rapidly and resemble a burst of fireworks. We have also analyzed small cutout WISE images of the structures around the edges of these massive star-forming regions. We observe large (1-3 pc size) pillar and trunk-like structures of diffuse emission nebulosity tracing excited polycyclic aromatic hydrocarbon molecules and small dust grains at the perimeter of the massive star-forming regions. These structures contain small clusters of emerging Class I and Class II sources, but some are forming only a single to a few new stars.

  12. Wide-Field Infrared Survey Explorer Observations of the Evolution of Massive Star-Forming Regions

    NASA Technical Reports Server (NTRS)

    Koenig, X. P.; Leisawitz, D. T.; Benford, D. J.; Rebull, L. M.; Padgett, D. L.; Assef, R. J.

    2011-01-01

    We present the results of a mid-infrared survey of 11 outer Galaxy massive star-forming regions and 3 open clusters with data from the Wide-field Infrared Survey Explorer (WISE). Using a newly developed photometric scheme to identify young stellar objects and exclude extragalactic contamination, we have studied the distribution of young stars within each region. These data tend to support the hypothesis that latter generations may be triggered by the interaction of winds and radiation from the first burst of massive star formation with the molecular cloud material leftover from that earlier generation of stars.We dub this process the "fireworks hypothesis" since star formation by this mechanism would proceed rapidly and resemble a burst of fireworks.We have also analyzed small cutout WISE images of the structures around the edges of these massive star-forming regions. We observe large (1-3 pc size) pillar and trunk-like structures of diffuse emission nebulosity tracing excited polycyclic aromatic hydrocarbon molecules and small dust grains at the perimeter of the massive star-forming regions. These structures contain small clusters of emerging Class I and Class II sources, but some are forming only a single to a few new stars.

  13. Progression of gyrate atrophy measured with ultra-wide-field imaging.

    PubMed

    Salcedo-Villanueva, Guillermo; Paciuc-Beja, Miguel; Villanueva-Mendoza, Cristina; Harasawa, Mariana; Smith, Jesse M; Velez-Montoya, Raul; Olson, Jeffrey L; Oliver, Scott C; Mandava, Naresh; Quiroz-Mercado, Hugo

    2016-02-01

    The study aims to determine the progression of gyrate atrophy by measuring the area growth of chorioretinal atrophic lesions using ultra-wide-field images (UWFI). A retrospective, observational, and comparative study was conducted and UWFI (200°) were obtained from two patients with gyrate atrophy at baseline and follow-up. Measurements of atrophy were obtained for three types of lesions: Solitary atrophic lesions (SAL), De novo solitary lesions (DNSL), and peripapillary atrophy (PPA). Comparison of baseline and follow-up was done using t tests. Two patients with gyrate atrophy were included. Patient 1 presented 16 SAL, 5 DNSL, and PPA measured for both eyes (BE). Overall area growth (OAG) for SAL (expressed in decimals) presented a mean of 3.41, σ 3.07. DNSL area for BE presented a mean of 1586.08 P (2), σ 1069.55. OAG for PPA presented a mean of 1.21, σ 0.17. Patient 2 presented 5 SAL, no DNSL, and PPA was measured for BE. OAG for SAL presented a mean of 1.58, σ 1.05 (range 1.02-3.47). OAG for PPA presented a mean of 1.05, σ 0.001. Gyrate atrophy progression can be determined by measuring the changes in area using UWFI.

  14. A TECHNIQUE FOR PRIMARY BEAM CALIBRATION OF DRIFT-SCANNING, WIDE-FIELD ANTENNA ELEMENTS

    SciTech Connect

    Pober, Jonathan C.; Parsons, Aaron R.; Jacobs, Daniel C.; Aguirre, James E.; Moore, David F.; Bradley, Richard F.; Parashare, Chaitali R.; Carilli, Chris L.; Gugliucci, Nicole E.

    2012-02-15

    We present a new technique for calibrating the primary beam of a wide-field, drift-scanning antenna element. Drift-scan observing is not compatible with standard beam calibration routines, and the situation is further complicated by difficult-to-parameterize beam shapes and, at low frequencies, the sparsity of accurate source spectra to use as calibrators. We overcome these challenges by building up an interrelated network of source 'crossing points'-locations where the primary beam is sampled by multiple sources. Using the single assumption that a beam has 180 Degree-Sign rotational symmetry, we can achieve significant beam coverage with only a few tens of sources. The resulting network of crossing points allows us to solve for both a beam model and source flux densities referenced to a single calibrator source, circumventing the need for a large sample of well-characterized calibrators. We illustrate the method with actual and simulated observations from the Precision Array for Probing the Epoch of Reionization.

  15. WIDE-FIELD WIDE-BAND INTERFEROMETRIC IMAGING: THE WB A-PROJECTION AND HYBRID ALGORITHMS

    SciTech Connect

    Bhatnagar, S.; Rau, U.; Golap, K. E-mail: rurvashi@nrao.edu

    2013-06-20

    Variations of the antenna primary beam (PB) pattern as a function of time, frequency, and polarization form one of the dominant direction-dependent effects at most radio frequency bands. These gains may also vary from antenna to antenna. The A-Projection algorithm, published earlier, accounts for the effects of the narrow-band antenna PB in full polarization. In this paper, we present the wide-band A-Projection algorithm (WB A-Projection) to include the effects of wide bandwidth in the A-term itself and show that the resulting algorithm simultaneously corrects for the time, frequency, and polarization dependence of the PB. We discuss the combination of the WB A-Projection and the multi-term multi-frequency synthesis (MT-MFS) algorithm for simultaneous mapping of the sky brightness distribution and the spectral index distribution across a wide field of view. We also discuss the use of the narrow-band A-Projection algorithm in hybrid imaging schemes that account for the frequency dependence of the PB in the image domain.

  16. Preliminary Results from the Wide-field Infrared Survey Explorer's NEOWISE Search for Minor Planets

    NASA Astrophysics Data System (ADS)

    Mainzer, A.; Bauer, J. M.; Grav, T.; Masiero, J.; McMillan, R. S.; Walker, R.; Tholen, D. J.; Wright, E.; Eisenhardt, P.; Cutri, R.; Neowise Team

    2011-12-01

    The Wide-Field Infrared Survey Explorer (WISE) imaged the entire sky twice between January, 2010 and January, 2011 at four wavelengths spanning the near through mid-IR at sensitivities hundreds of times greater than previous surveys [1]. The WISE band-passes (3.4, 4.6, 12 and 22mm) sample the flux from most inner-solar-system bodies near the peak of their thermal emission. Overlapping sky regions were sampled repeatedly at 3 hour intervals. The same region of sky was observed a minimum of 8 times. While the primary WISE science objectives focus on ultra-luminous infrared galaxies and brown dwarfs, additions to the baseline WISE pipeline (collectively known as "NEOWISE") have enabled the detection of undiscovered moving objects, as well as previously known bodies [2]. NEOWISE has detected more than 155,000 minor planets, including more than 500 near-Earth objects (NEOs), ~2000 Jupiter Trojans, ~120 comets, and ~20 outer Solar System objects such as Centaurs. The survey has discovered ~34,000 new minor planets, including 130 new NEOs and 20 new comets. The NEOWISE data will drive a wide range of new Solar System investigations. NEOWISE allows precise determination of IR-derived diameters and albedos for minor planets throughout the Solar System [3],[4]. We will summarize the latest results from the project, including studies of the statistical properties of asteroid populations such as the NEOs, and comparisons between albedo and asteroid taxonomic classification.

  17. Calibration of HST wide field camera for quantitative analysis of faint galaxy images

    NASA Technical Reports Server (NTRS)

    Ratnatunga, Kavan U.; Griffiths, Richard E.; Casertano, Stefano; Neuschaefer, Lyman W.; Wyckoff, Eric W.

    1994-01-01

    We present the methods adopted to optimize the calibration of images obtained with the Hubble Space Telescope (HST) Wide Field Camera (WFC) (1991-1993). Our main goal is to improve quantitative measurement of faint images, with special emphasis on the faint (I approximately 20-24 mag) stars and galaxies observed as a part of the Medium-Deep Survey. Several modifications to the standard calibration procedures have been introduced, including improved bias and dark images, and a new supersky flatfield obtained by combining a large number of relatively object-free Medium-Deep Survey exposures of random fields. The supersky flat has a pixel-to-pixel rms error of about 2.0% in F555W and of 2.4% in F785LP; large-scale variations are smaller than 1% rms. Overall, our modifications improve the quality of faint images with respect to the standard calibration by about a factor of five in photometric accuracy and about 0.3 mag in sensitivity, corresponding to about a factor of two in observing time. The relevant calibration images have been made available to the scientific community.

  18. Deployment of the Hobby-Eberly Telescope wide-field upgrade

    NASA Astrophysics Data System (ADS)

    Hill, Gary J.; Drory, Niv; Good, John M.; Lee, Hanshin; Vattiat, Brian L.; Kriel, Herman; Ramsey, Jason; Bryant, Randy; Elliot, Linda; Fowler, Jim; Häuser, Marco; Landiau, Martin; Leck, Ron; Odewahn, Stephen; Perry, Dave; Savage, Richard; Schroeder Mrozinski, Emily; Shetrone, Matthew; DePoy, D. L.; Prochaska, Travis; Marshall, J. L.; Damm, George; Gebhardt, Karl; MacQueen, Phillip J.; Martin, Jerry; Armandroff, Taft; Ramsey, Lawrence W.

    2016-07-01

    The Hobby-Eberly Telescope (HET) is an innovative large telescope, located in West Texas at the McDonald Observatory. The HET operates with a fixed segmented primary and has a tracker, which moves the four-mirror corrector and prime focus instrument package to track the sidereal and non-sidereal motions of objects. We have completed a major multi-year upgrade of the HET that has substantially increased the pupil size to 10 meters and the field of view to 22 arcminutes by replacing the corrector, tracker, and prime focus instrument package. The new wide field HET will feed the revolutionary integral field spectrograph called VIRUS, in support of the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX§), a new low resolution spectrograph (LRS2), an upgraded high resolution spectrograph (HRS2), and later the Habitable Zone Planet Finder (HPF). The upgrade is being commissioned and this paper discusses the completion of the installation, the commissioning process and the performance of the new HET.

  19. Ultraviolet Raman Wide-Field Hyperspectral Imaging Spectrometer for Standoff Trace Explosive Detection.

    PubMed

    Hufziger, Kyle T; Bykov, Sergei V; Asher, Sanford A

    2017-02-01

    We constructed the first deep ultraviolet (UV) Raman standoff wide-field imaging spectrometer. Our novel deep UV imaging spectrometer utilizes a photonic crystal to select Raman spectral regions for detection. The photonic crystal is composed of highly charged, monodisperse 35.5 ± 2.9 nm silica nanoparticles that self-assemble in solution to produce a face centered cubic crystalline colloidal array that Bragg diffracts a narrow ∼1.0 nm full width at half-maximum (FWHM) UV spectral region. We utilize this photonic crystal to select and image two different spectral regions containing resonance Raman bands of pentaerythritol tetranitrate (PETN) and NH4NO3 (AN). These two deep UV Raman spectral regions diffracted were selected by angle tuning the photonic crystal. We utilized this imaging spectrometer to measure 229 nm excited UV Raman images containing ∼10-1000 µg/cm(2) samples of solid PETN and AN on aluminum surfaces at 2.3 m standoff distances. We estimate detection limits of ∼1 µg/cm(2) for PETN and AN films under these experimental conditions.

  20. THE FIRST ULTRA-COOL BROWN DWARF DISCOVERED BY THE WIDE-FIELD INFRARED SURVEY EXPLORER

    SciTech Connect

    Mainzer, A.; Cushing, Michael C.; Eisenhardt, P.; Skrutskie, M.; Beaton, R.; Gelino, C. R.; Kirkpatrick, J. Davy; Jarrett, T.; Masci, F.; Marsh, K.; Padgett, D.; Marley, Mark S.; Saumon, D.; Wright, E.; McLean, I.; Dietrich, M.; Garnavich, P.; Rueff, K.; Kuhn, O.; Leisawitz, D.

    2011-01-01

    We report the discovery of the first new ultra-cool brown dwarf (BDs) found with the Wide-field Infrared Survey Explorer (WISE). The object's preliminary designation is WISEPC J045853.90+643451.9. Follow-up spectroscopy with the LUCIFER instrument on the Large Binocular Telescope indicates that it is a very late-type T dwarf with a spectral type approximately equal to T9. Fits to an IRTF/SpeX 0.8-2.5 {mu}m spectrum to the model atmospheres of Marley and Saumon indicate an effective temperature of approximately 600 K as well as the presence of vertical mixing in its atmosphere. The new BD is easily detected by WISE, with a signal-to-noise ratio of {approx}36 at 4.6 {mu}m. Current estimates place it at a distance of 6-10 pc. This object represents the first in what will likely be hundreds of nearby BDs found by WISE that will be suitable for follow-up observations, including those with the James Webb Space Telescope. One of the two primary scientific goals of the WISE mission is to find the coolest, closest stars to our Sun; the discovery of this new BD proves that WISE is capable of fulfilling this objective.