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1

Wide field optical and IR spectroscopy at the ING: present and future prospects  

NASA Astrophysics Data System (ADS)

The present status and performance of the fibre positioner AUTOFIB2 and spectrograph WYFFOS are reviewed. After extensive re-engineering of the AUTOFIB2 robot and fibre module, the system is now reliable, setting up a science field in under 30 min with better than 10 ?m internal accuracy (the original specifications). Since the rebuild AUTOFIB2 has been scheduled on some 50 nights and undergone more than 50?000 fibre movements with only one failure (and a number of back illumination failures of a minor nature). WYFFOS is now fully commissioned in both reflection and 'echelle' mode. By summer 2001 both the small fibre module (1.6 arcsec diameter) and the WYFFOS long camera will be commissioned. These upgrades will make this system amongst the most sensitive on any 4 m telescope. A series of relatively minor software and fibre module upgrades are also proposed (some of which will be implemented soon) which will allow 150 fibre movements in 10-15 min and crossing fibres. Further in the future we propose the development of a fibre module and WYFFOS optics optimized for the near IR and also a small fibre module containing 600 fibres (2 fibres per button) that at the very least will be useful for sky subtraction and beam-switching (depending on technological developments).

Pollacco, D. L.; Smartt, S. J.

2001-01-01

2

The DESI wide field corrector optics  

NASA Astrophysics Data System (ADS)

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 designed 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 cost. 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.

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

2014-08-01

3

Wide field strip-imaging optical system  

NASA Technical Reports Server (NTRS)

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.

Vaughan, Arthur H. (inventor)

1994-01-01

4

Optical transient search strategy via wide-field monitoring  

NASA Astrophysics Data System (ADS)

We discuss the search strategy of fast optical transients accompanying gamma-ray bursts in wide-field monitoring. We describe the instrumentation and methods of observational data reduction, allowing to detect optical flashes brighter than 10-11 stellar magnitudes with temporal resolution of 0.13 s. The prospects of both instrument engineering, as well as development of techniques to search and investigate optical transients of various nature in wide fields are also discussed.

Beskin, G.; Bondar, S.; Karpov, S.; Plokhotnichenko, V.; Guarnieri, A.; Bartolini, C.; Greco, D.; Piccioni, A.

2010-07-01

5

Adaptive Optics Calibration for a Wide-Field Microscope Janice Castillo*  

E-print Network

Adaptive Optics Calibration for a Wide-Field Microscope Janice Castillo* and Thomas Bifano Boston calibration of a novel wide-field scanning microscope is described, comparing relevant parameters for several, microscopy 1. INTRODUCTION The Adaptive Scanning Optical Microscope (ASOM, Thorlabs, Inc.) is a new type

6

Telescope with a wide field of view internal optical scanner  

NASA Technical Reports Server (NTRS)

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.

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

2012-01-01

7

The next generation of wide field adaptive optics  

Microsoft Academic Search

In the last decade, adaptive optics systems have been implemented on all the major ground based telescopes and have proven reliable tools for correcting the image to near the diffraction limit. However, the correction from these systems is limited to a narrow field of view. This dissertation address the challenges of widening the corrected field of single conjugate adaptive optics

Jeffrey A. Stoesz

2006-01-01

8

Optimal grazing incidence optics and its application to wide-field X-ray imaging  

Microsoft Academic Search

A class of high-resolution, efficient, and wide-field grazing incidence optics is discussed. Optical designs for searching efficiently for distant X-ray clusters are developed. It is shown that a rather general procedure exists for the design of an optical mission if well-defined scientific goals can be provided. Clusters of galaxies with an angular diameter of about 5 arcsec over a field

Christopher J. Burrows; Richard Burg; Riccardo Giacconi

1992-01-01

9

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

PubMed Central

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 ?m 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. PMID:21045887

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

2010-01-01

10

Performance Modeling of a Wide-Field Ground-Layer Adaptive Optics System  

Microsoft Academic Search

Using five independent analytic and Monte Carlo simulation codes, we have studied the performance of wide-field ground-layer adaptive optics (GLAO), which can use a single, relatively low order deformable mirror to correct the wave-front errors from the lowest altitude turbulence. GLAO concentrates more light from a point source in a smaller area on the science detector, but unlike with traditional

David R. Andersen; Jeff Stoesz; Simon Morris; Michael Lloyd-Hart; David Crampton; Tim Butterley; Brent Ellerbroek; Laurent Jolissaint; N. Mark Milton; Richard Myers; Kei Szeto; Andrei Tokovinin; Jean-Pierre Véran; Richard Wilson

2006-01-01

11

Off-axis catadioptric fisheye wide field-of-view optical receiver for free space optical communications  

NASA Astrophysics Data System (ADS)

We propose a wide field-of-view optical receiver design based on a fisheye lens and an off-axis catadioptric structure for free-space optical communications. The design utilizes a novel fisheye lens group to compress a wide field angle into a narrow field angle and produce the appropriately collimated light that can effectively be coupled into the following aperture of a catadioptric telescope. An off-axis catadioptric telescope with aspheric surface mirrors is designed to compress the incident beam spot size, compensate for the high order optical aberrations and eliminate light loss due to an obstruction. The parallel exit rays are reflected on a double-level tracking mechanism by feeding the position signal from a quadrant detector to correct the pointing error and optimize the coupling efficiency into an optical fiber. The final wide field-of-view optical receiver design is presented along with the evaluation of optical performance results and tracking characteristics. The proposed optical receiver not only can provide a 60-deg wide field-of-view to expand the tracking range, but also mitigates optical aberrations to improve the tracking accuracy for free space optical communication systems in a turbulent atmosphere.

Deng, Peng; Yuan, XiuHua; Kavehrad, Mohsen; Zhao, Ming; Zeng, YanAn

2012-06-01

12

Modelling the application of adaptive optics to wide-field microscope live imaging.  

PubMed

Wide-field fluorescence microscopy is an essential tool in modern cell biology. Unfortunately the image quality of fluorescence microscopes is often significantly degraded due to aberrations that occur under normal imaging conditions. In this article, we examine the use of adaptive optics technology to dynamically correct these problems to achieve close to ideal diffraction limited performance. Simultaneously, this technology also allows ultra-rapid focusing without having to move either the stage or the objective lens. We perform optical simulations to demonstrate the degree of correction that can be achieved. PMID:17381707

Kam, Zvi; Kner, Peter; Agard, David; Sedat, John W

2007-04-01

13

Final Optical Design of PANIC, a Wide-Field Infrared Camera for CAHA  

NASA Astrophysics Data System (ADS)

We present the Final Optical Design of PANIC (PAnoramic Near Infrared camera for Calar Alto), a wide-field infrared imager for the Ritchey-Chrtien focus of the Calar Alto 2.2 m telescope. This will be the first instrument built under the German-Spanish consortium that manages the Calar Alto observatory. 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 ?m pixel. The optical design produces a well defined internal pupil available to reducing the thermal background by a cryogenic pupil stop. A mosaic of four detectors Hawaii 2RG of 2 k ×2 k, made by Teledyne, will give a field of view of 31.9 arcmin ×31.9 arcmin.

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

14

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

NASA Astrophysics Data System (ADS)

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.

Schipani, P.; Perrotta, F.

2008-07-01

15

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

E-print Network

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 with constraints on the redshift (0.0420). 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 to define 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. In addition, a NIR (JK) survey of ~50 clusters and an H_alpha + UV survey of some 10 clusters are presently ongoing, while a very-wide-field optical survey has also been programmed. 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 ~0.025mag, 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 get a valuable description of the local properties of clusters and galaxies in clusters.

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

2005-10-05

16

Developments of wide field submillimeter optics and lens antenna-coupled MKID cameras  

NASA Astrophysics Data System (ADS)

Wide field cryogenic optics and millimeter-wave Microwave Kinetic Inductance Detector (MKID) cameras with Si lens array have been developed. MKID is a Cooper-pair breaking photon detector and consists of supercon- ducting resonators which enable microwave (~GHz) frequency multiplexing. Antenna-coupled Aluminum CPW resonators are put in a line on a Si substrate to be read by a pair of coaxial cables. A 220 GHz - 600 pixels MKID camera with anti-reflection (AR) coated Si lens has been demonstrated in an 0.1 K cryostat. A compact cryogenic system with high refractive index materials has been developed for the MKID camera.

Sekimoto, Y.; Nitta, T.; Karatsu, K.; Sekine, M.; Sekiguchi, S.; Okada, T.; Shu, S.; Noguchi, T.; Naruse, M.; Mitsui, K.; Okada, N.; Tsuzuki, T.; Dominjon, A.; Matsuo, H.

2014-07-01

17

Wide field adaptive optics laboratory demonstration with closed-loop tomographic control.  

PubMed

HOMER, the new bench developed at ONERA devoted to wide field adaptive optics (WFAO) laboratory research, has allowed the first experimental validations of multi-conjugate adaptive optics (MCAO) and laser tomography adaptive optics (LTAO) concepts with a linear quadratic Gaussian (LQG) control approach. Results obtained in LTAO in closed loop show the significant gain in performance brought by LQG control, which allows tomographic reconstruction. We present a calibration and model identification strategy. Experimental results are shown to be consistent with end-to-end simulations. These results are very encouraging and demonstrate robustness of performance with respect to inevitable experimental uncertainties. They represent a first step for the study of very large telescope (VLT) and extremely large telescopes (ELT) instruments. PMID:20208937

Costille, Anne; Petit, Cyril; Conan, Jean-Marc; Kulcsár, Caroline; Raynaud, Henri-François; Fusco, Thierry

2010-03-01

18

Wide-field two-dimensional multifocal optical-resolution photoacoustic computed microscopy  

PubMed Central

Optical-resolution photoacoustic microscopy (OR-PAM) is an emerging technique that directly images optical absorption in tissue at high spatial resolution. To date, the majority of OR-PAM systems are based on single focused optical excitation and ultrasonic detection, limiting the wide-field imaging speed. While one-dimensional multifocal OR-PAM (1D-MFOR-PAM) has been developed, the potential of microlens and transducer arrays has not been fully realized. Here, we present the development of two-dimensional multifocal optical-resolution photoacoustic computed microscopy (2D-MFOR-PACM), using a 2D microlens array and a full-ring ultrasonic transducer array. The 10 × 10 mm2 microlens array generates 1800 optical foci within the focal plane of the 512-element transducer array, and raster scanning the microlens array yields optical-resolution photoacoustic images. The system has improved the in-plane resolution of a full-ring transducer array from ?100 µm to 29 µm and achieved an imaging time of 36 seconds over a 10 × 10 mm2 field of view. In comparison, the 1D-MFOR-PAM would take more than 4 minutes to image over the same field of view. The imaging capability of the system was demonstrated on phantoms and animals both ex vivo and in vivo. PMID:24322226

Xia, Jun; Li, Guo; Wang, Lidai; Nasiriavanaki, Mohammadreza; Maslov, Konstantin; Engelbach, John A.; Garbow, Joel R.; Wang, Lihong V.

2014-01-01

19

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

NASA Astrophysics Data System (ADS)

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.

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

2014-09-01

20

Analysis of the lateral displacement and optical path difference in wide-field-of-view polarization interference imaging spectrometer  

Microsoft Academic Search

The mechanism of beam splitting and principle of wide-field-of-view compensation of modified Savart polariscope in the wide-field-of-view polarization interference imaging spectrometer (WPIIS) are analyzed and discussed. Formulas for the lateral displacement and optical path difference (OPD) produced by the modified Savart polariscope are derived by ray-tracing method. The theoretical and practical guidance is thereby provided for the study, design, modulation,

Lei Wu; Chunmin Zhang; Baochang Zhao

2007-01-01

21

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

PubMed Central

We demonstrate lensless fluorescent microscopy over a large field-of-view of ~60 mm2 with a spatial resolution of <4 ?m. 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 ?m) 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. PMID:21283900

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

2011-01-01

22

Optimizing X-Ray Optical Prescriptions for Wide-Field Applications  

NASA Technical Reports Server (NTRS)

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).

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

2010-01-01

23

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

NASA Astrophysics Data System (ADS)

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.

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

24

Fast wide-field photothermal and quantitative phase cell imaging with optical lock-in detection  

PubMed Central

We present a fast, wide-field holography system for detecting photothermally excited gold nanospheres with combined quantitative phase imaging. An interferometric photothermal optical lock-in approach (POLI) is shown to improve SNR for detecting nanoparticles (NPs) on multiple substrates, including a monolayer of NPs on a silanized coverslip, and NPs bound to live cells. Furthermore, the set up allowed for co-registered quantitative phase imaging (QPI) to be acquired in an off-axis holographic set-up. An SNR of 103 was obtained for NP-tagging of epidermal growth factor receptor (EGFR) in live cells with a 3 second acquisition, while an SNR of 47 was seen for 20 ms acquisition. An analysis of improvements in SNR due to averaging multiple frames is presented, which suggest that residual photothermal signal can be a limiting factor. The combination of techniques allows for high resolution imaging of cell structure via QPI with the ability to identify receptor expression via POLI. PMID:25136482

Eldridge, Will J.; Meiri, Amihai; Sheinfeld, Adi; Rinehart, Matthew T.; Wax, Adam

2014-01-01

25

Fast wide-field photothermal and quantitative phase cell imaging with optical lock-in detection.  

PubMed

We present a fast, wide-field holography system for detecting photothermally excited gold nanospheres with combined quantitative phase imaging. An interferometric photothermal optical lock-in approach (POLI) is shown to improve SNR for detecting nanoparticles (NPs) on multiple substrates, including a monolayer of NPs on a silanized coverslip, and NPs bound to live cells. Furthermore, the set up allowed for co-registered quantitative phase imaging (QPI) to be acquired in an off-axis holographic set-up. An SNR of 103 was obtained for NP-tagging of epidermal growth factor receptor (EGFR) in live cells with a 3 second acquisition, while an SNR of 47 was seen for 20 ms acquisition. An analysis of improvements in SNR due to averaging multiple frames is presented, which suggest that residual photothermal signal can be a limiting factor. The combination of techniques allows for high resolution imaging of cell structure via QPI with the ability to identify receptor expression via POLI. PMID:25136482

Eldridge, Will J; Meiri, Amihai; Sheinfeld, Adi; Rinehart, Matthew T; Wax, Adam

2014-08-01

26

The New Milky Way: A Wide-Field Survey of Optical Transients near the Galactic plane  

NASA Astrophysics Data System (ADS)

Currently, it may take days for a bright nova outburst to be detected. With a few exceptions, little is known about novae behaviour prior to maximum light. A theoretically-predicted population of ultra-fast novae with t2<1d is evading observational discovery because it is not possible to routinely organize fast follow-up observations of nova candidates. With the aim of bringing the detection time of novae and other bright (V<13.5) optical transients from days down to hours or less, we developed an automated wide-field (8°×6°) system capable of surveying the whole Milky Way area visible from the observing site in one night. The system is built using low-cost mass-produced components and the transient detection pipeline is based on the open source VaST software. We describe the instrument design and report results of the first observations conducted in 2011 October-November and 2012 January-April. The results include the discovery of Nova Sagittarii 2012 No. 1 as well as two X-ray emitting cataclysmic variables 1RXS J063214.8+25362 and XMMSL1 J014956.7+533504. The rapid detection of Nova Sagittarii 2012 No. 1 enabled us to conduct its X-ray and UV observations with Swift 22 hours after discovery (˜eq 31 hour after the outburst onset). All images obtained during the transient search survey are available online.

Sokolovsky, K.; Korotkiy, S.; Lebedev, A.

2014-12-01

27

Scanner-Free and Wide-Field Endoscopic Imaging by Using a Single Multimode Optical Fiber Youngwoon Choi,1  

E-print Network

. Therefore, the requirement for a large number of fibers for high resolution imaging has posed constraints as a single pixel of an image, and the number of fibers in the bundle deter- mines the pixel resolutionScanner-Free and Wide-Field Endoscopic Imaging by Using a Single Multimode Optical Fiber Youngwoon

Fang-Yen, Christopher

28

ANDROMEDA (M31) OPTICAL AND INFRARED DISK SURVEY. I. INSIGHTS IN WIDE-FIELD NEAR-IR SURFACE PHOTOMETRY  

E-print Network

We present wide-field near-infrared J and K[subscript 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 ...

Sick, Jonathan

29

Optical diagnostic equipment for evaluating a wide field of view phased array telescope  

Microsoft Academic Search

A key feature of the Multipurpose Multiple Telescope Testbed (MMTT) is its relatively wide field of view -- up to 30 arcminutes total. A thorough evaluation of the telescope array necessitates some form of image analysis over this field. System designers chose the star test, here modified to simltaneously display point spread functions (PSFs) at several locations in the image

R. C. Dymale; J. P. Blea

1990-01-01

30

High-resolution wide-field standing-wave surface plasmon resonance fluorescence microscopy with optical vortices  

Microsoft Academic Search

A technique for high-resolution wide-field fluorescence microscopy by using standing surface plasmon waves induced by optical vortices (OVs) is proposed, aiming at harnessing its unique dynamic properties to sequentially illuminate specimen with different phase-shifted interference excitation field. Topological charges of the OV are employed to modulate phase-shifting of the interference pattern. Numerical studies and experimental results reveal an achievement of

P. S. Tan; X.-C. Yuan; G. H. Yuan; Q. Wang

2010-01-01

31

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

NASA Technical Reports Server (NTRS)

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.

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

2011-01-01

32

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

NASA Astrophysics Data System (ADS)

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.

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

2003-02-01

33

Multiple scattering in optical coherence tomography. II. Experimental and theoretical investigation of cross talk in wide-field optical coherence tomography  

Microsoft Academic Search

We present a comprehensive study of multiple-scattering effects in wide-field optical coherence tomography (OCT) realized with spatially coherent illumination. Imaging a sample made of a cleaved mirror embedded in an aqueous suspension of microspheres revealed that, despite temporal coherence gating, multiple scattering can induce significant coherent optical cross talk. The latter is a serious limitation to the method, since it

Boris Karamata; Marcel Leutenegger; Markus Laubscher; Stéphane Bourquin; Theo Lasser; Patrick Lambelet

2005-01-01

34

Scanner-Free and Wide-Field Endoscopic Imaging by Using a Single Multimode Optical Fiber  

E-print Network

A single multimode fiber is considered an ideal optical element for endoscopic imaging due to the possibility of direct image transmission via multiple spatial modes. However, the wave distortion induced by the mode ...

Choi, Youngwoon

35

Design of wide-field Nasmyth optics for a submillimeter camera  

NASA Astrophysics Data System (ADS)

We designed wide FoV (1 degree) Nasmyth optics which transformed the f/6 Nasmyth focus to f/1 at a 850GHz superconducting camera for a planning 10-m Ritchey-Chrétien telescope. This optical system consists of reflecting mirrors at room temperature and a refractive lens at 4K. It enables us to carry out wide FoV imaging observations at the diffraction limit (Strehl ratio < 0.89) with a more than 100,000 pixel camera equipped in a 10-m telescope. The size of this system is reasonably compact (whole size:1.6 mx3.3 mx2.6 m, cryogenic part:0.7 mx0.7 mx1.0 m). The cryogenic part of this system such as vacuum window, cryogenic lens and IR block filters can be made with existing technologies at reasonable cost. The optical system can extend to the millimeter wave and the terahertz domain.

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

2014-07-01

36

Off-axis catadioptric fisheye wide field-of-view optical receiver for free space  

E-print Network

collimated light that can effectively be coupled into the fol- lowing aperture of a catadioptric telescope signal from a quadrant detector to correct the pointing error and optimize the coupling efficiency, optical links are strongly affected by atmospheric turbulence. Hence, acquisition, tracking, and pointing

Kavehrad, Mohsen

37

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

NASA Technical Reports Server (NTRS)

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.

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

1992-01-01

38

Tolerancing the fabrication errors of static optical elements for ELT-size wide-field AO systems  

NASA Astrophysics Data System (ADS)

Advanced wide-field AO systems, such as Multi-Conjugate AO (MCAO) systems often require many static optical elements (mirror and lenses) in addition to the active ones (deformable mirrors). These static elements induce additional wave-front errors due to random fabrication errors such as polishing errors. For ELT-size AO systems, these optical elements can be very large, and thus their cost and availability critically depends on how of much fabrication error can be tolerated. Therefore, a rigorous tolerance analysis is absolutely critical. Requirements can, in principle be relaxed, on account that fabrication errors with spatial scales larger than the inter-actuator spacing of the deformable mirrors (DMs) can be corrected. However, this process is significantly complicated by the fact that these optical elements are often conjugated far away from the DMs, and therefore DM correction cannot be achieved over a wide field of view (FOV). In this paper, we present our tolerance analysis in the context of NFIRAOS, the first-light MCAO system for the Thirty Meter Telescope. We start from two top-level error budgets: the “on-axis” error budget, which specifies the acceptable residual wave-front error in the narrow 17”x17” science FOV; and the “off-axis” error budget, which specifies the acceptable residual wave-front error at the edge of the 2’ diameter technical FOV. The former directly relates to science image quality, whereas the latter directly relates to sky coverage. For different assumptions on the spatial power spectrum of the polishing errors, we derive the requirements on each optical element in NFIRAOS using a Monte-Carlo analysis of the predicted off-axis performance of the system with on axis AO correction.

Véran, Jean-Pierre; Pazder, John; Herriot, Glen; Andersen, David

2012-07-01

39

Accounting for anisoplanatic point spread function in deep wide-field adaptive optics images  

E-print Network

In this paper we present the approach we have used to determine and account for the anisoplanatic point spread function (PSF) in deep adaptive optics (AO) images for the Survey of a Wide Area with NACO (SWAN) at the ESO VLT. The survey comprises adaptive optics observations in the Ks band totaling ~ 30 arcmin^2, assembled from 42 discrete fields centered on different bright stars suitable for AO guiding. We develop a parametric model of the PSF variations across the field of view in order to build an accurate model PSF for every galaxy detected in each of the fields. We show that this approach is particularly convenient, as it uses only easily available data and makes no uncertain assumptions about the stability of the isoplanatic angle during any given night. The model was tested using simulated galaxy profiles to check its performance in terms of recovering the correct morphological parameters; we find that the results are reliable up to Ks ~ 20.5 (K_AB ~ 22.3) in a typical SWAN field. Finally, the model obtained was used to derive the first results from five SWAN fields, and to obtain the AO morphology of 55 galaxies brighter than Ks = 20. These preliminary results demonstrate the unique power of AO observations to derive the details of faint galaxy morphologies and to study galaxy evolution.

G. Cresci; R. I. Davies; A. J. Baker; M. D. Lehnert

2005-04-21

40

Design of a four-mirror optical system with wide field of view  

NASA Astrophysics Data System (ADS)

Reflective optics is used widely in space optical systems for their achromatization, large aperture and lightweight compared with refractive systems. Four-mirror system especially off-axis system is desired for its excellent imaging performance and compact structure. Aberration theory of coaxial four-mirror system based on PW method is analyzed and the design procedure is proposed to get the initial four-mirror system in this paper. A large field off-axis four-mirror system is designed based on the theory and the design process. The system contains four conic aspheric mirrors. It has a 2°×0.32° rectangular field of view. The MTF of the system is diffraction-limited and the distortion is less than 0.1%. The structure of the system is compact and the ratio of total axis length to focal length is about 1/3.9. The excellent imaging performance and compact structure make it adaptable to space remote sensing systems.

Liang, Shi-tong; Yang, Jian-feng; Xue, Bin; Ruan, Ping

2010-11-01

41

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

NASA Astrophysics Data System (ADS)

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.

Sydney, P.; Wetterer, C.

2014-09-01

42

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

NASA Astrophysics Data System (ADS)

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.

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

2014-10-01

43

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

NASA Technical Reports Server (NTRS)

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.

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

2011-01-01

44

Wide field of view telescope  

DOEpatents

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.

Ackermann, Mark R. (Albuquerque, NM); McGraw, John T. (Placitas, NM); Zimmer, Peter C. (Albuquerque, NM)

2008-01-15

45

Aerosol variability in the Adriatic Sea from automated optical field measurements and Sea-viewing Wide Field-of-view Sensor (SeaWiFS)  

Microsoft Academic Search

The aerosol optical properties in the Adriatic Sea are presented using a 9-year time series (1996-2005) of automated measurements collected on the Acqua Alta Oceanographic Tower (AAOT) in the northern part of the basin and a coincident satellite record obtained from an atmospheric correction scheme adapted for European seas and applied to the Sea-viewing Wide Field-of-view Sensor (SeaWiFS). At AAOT,

F. Mélin; M. Clerici; G. Zibordi; B. Bulgarelli

2006-01-01

46

High-resolution wide-field microscopy with adaptive optics for spherical aberration correction and motionless focusing.  

PubMed

Live imaging in cell biology requires three-dimensional data acquisition with the best resolution and signal-to-noise ratio possible. Depth aberrations are a major source of image degradation in three-dimensional microscopy, causing a significant loss of resolution and intensity deep into the sample. These aberrations occur because of the mismatch between the sample refractive index and the immersion medium index. We have built a wide-field fluorescence microscope that incorporates a large-throw deformable mirror to simultaneously focus and correct for depth aberration in three-dimensional imaging. Imaging fluorescent beads in water and glycerol with an oil immersion lens we demonstrate a corrected point spread function and a 2-fold improvement in signal intensity. We apply this new microscope to imaging biological samples, and show sharper images and improved deconvolution. PMID:20096044

Kner, P; Sedat, J W; Agard, D A; Kam, Z

2010-02-01

47

High-resolution wide-field microscopy with adaptive optics for spherical aberration correction and motionless focusing  

PubMed Central

Summary Live imaging in cell biology requires three-dimensional data acquisition with the best resolution and signal-to-noise ratio possible. Depth aberrations are a major source of image degradation in three-dimensional microscopy, causing a significant loss of resolution and intensity deep into the sample. These aberrations occur because of the mismatch between the sample refractive index and the immersion medium index. We have built a wide-field fluorescence microscope that incorporates a large-throw deformable mirror to simultaneously focus and correct for depth aberration in three-dimensional imaging. Imaging fluorescent beads in water and glycerol with an oil immersion lens we demonstrate a corrected point spread function and a 2-fold improvement in signal intensity. We apply this new microscope to imaging biological samples, and show sharper images and improved deconvolution. PMID:20096044

Sedat, J.W.; Agard, D.A.; Kam, Z.

2010-01-01

48

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

PubMed Central

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. PMID:24358054

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

2013-01-01

49

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

NASA Astrophysics Data System (ADS)

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.

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

2013-03-01

50

The dawn of wide-field Sunyaev-Zel'dovich cluster surveys: Efficient optical follow-up  

NASA Astrophysics Data System (ADS)

The South Pole Telescope team has recently reported the first 21 galaxy clusters uniformly selected by a blind Sunyaev-Zel'dovich (SZ) survey. Prompt optical imaging has confirmed the existence of red-sequence galaxy overdensities at the SZ locations, and provided first estimates of their redshift and optical richness. We have also followed up a subset spectroscopically. These are some of the most massive clusters in the universe, spanning redshifts from z=0.15 to z>1, with median of 0.74. This remarkable sample serves as proof of concept for SZ cluster surveys, which will provide a new, powerful window on the nature of dark energy. We are attacking the problem of following up many hundreds or thousands of SZ detections in the coming years by developing a real-time photometric calibration tool called Stellar Locus Regression. We also attack it from a hardware standpoint by building PISCO, a simultaneous multiband CCD imager. Optimizing the observing strategy alone using SLR provides a factor of 2 in cluster-confirmation yield over standard methods, and PISCO gives another factor of 3 to 4 for z<1 clusters. Finally, we provide the first sky background characterization in the new CCD y band at Cerro Tololo in Chile, which will be used in next-generation astronomical camera systems and will provide useful additional information. as well as new challenges, for cluster studies such as this.

High, Fredrick William

51

Brightest X-Ray Clusters of Galaxies in the CFHTLS Wide Fields: Catalog and Optical Mass Estimator  

NASA Astrophysics Data System (ADS)

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.

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

2015-01-01

52

Using the Cn2 and wind profiler method with wide-field laser-guide-stars adaptive optics to quantify the frozen-flow decay  

NASA Astrophysics Data System (ADS)

We use the spatio-temporal cross-correlations of slopes from five Shack-Hartmann wavefront sensors to analyse the temporal evolution of the atmospheric turbulence layers at different altitudes. The focus is on the verification of the frozen-flow assumption. The data come from the Gemini South Multiconjugate Adaptive Optics System (GeMS). First, we present the Cn2 and wind profiling technique. This method provides useful information for the operation of the adaptive optics system, such as the number of existing turbulence layers, their associated velocities, altitudes and strengths, and also a mechanism to estimate the dome-seeing contribution to the total turbulence. Next, by identifying the turbulence layers, we show that it is possible to estimate the rate of decay in time of the correlation among turbulence measurements. We reduce on-sky data obtained during the 2011, 2012 and 2013 campaigns. The first results suggest that the rate of temporal decorrelation can be expressed in terms of a single parameter that is independent of the layer altitude and turbulence strength. Finally, we show that the decay rate of the frozen-flow contribution increases linearly with the layer speed. The observed evolution of the decay rate confirms the potential interest of the predictive control for wide-field adaptive optics systems.

Guesalaga, Andrés; Neichel, Benoit; Cortés, Angela; Béchet, Clémentine; Guzmán, Dani

2014-05-01

53

Self-Management of Patient Body Position, Pose, and Motion Using Wide-Field, Real-Time Optical Measurement Feedback: Results of a Volunteer Study  

SciTech Connect

Purpose: We present the results of a clinical feasibility study, performed in 10 healthy volunteers undergoing a simulated treatment over 3 sessions, to investigate the use of a wide-field visual feedback technique intended to help patients control their pose while reducing motion during radiation therapy treatment. Methods and Materials: An optical surface sensor is used to capture wide-area measurements of a subject's body surface with visualizations of these data displayed back to them in real time. In this study we hypothesize that this active feedback mechanism will enable patients to control their motion and help them maintain their setup pose and position. A capability hierarchy of 3 different level-of-detail abstractions of the measured surface data is systematically compared. Results: Use of the device enabled volunteers to increase their conformance to a reference surface, as measured by decreased variability across their body surfaces. The use of visual feedback also enabled volunteers to reduce their respiratory motion amplitude to 1.7 ± 0.6 mm compared with 2.7 ± 1.4 mm without visual feedback. Conclusions: The use of live feedback of their optically measured body surfaces enabled a set of volunteers to better manage their pose and motion when compared with free breathing. The method is suitable to be taken forward to patient studies.

Parkhurst, James M. [Developing Technologies, Christie Medical Physics and Engineering, The Christie NHS Foundation Trust, Manchester (United Kingdom); Price, Gareth J., E-mail: gareth.price@christie.nhs.uk [Developing Technologies, Christie Medical Physics and Engineering, The Christie NHS Foundation Trust, Manchester (United Kingdom); Faculty of Medical and Human Sciences, Manchester Academic Health Sciences Centre, University of Manchester, Manchester (United Kingdom); Sharrock, Phil J. [Developing Technologies, Christie Medical Physics and Engineering, The Christie NHS Foundation Trust, Manchester (United Kingdom); Jackson, Andrew S.N. [Clinical Oncology, Southampton University Hospitals Foundation Trust, Southampton (United Kingdom); Stratford, Julie [Department of Radiotherapy, The Christie NHS Foundation Trust, Manchester (United Kingdom); Moore, Christopher J. [Developing Technologies, Christie Medical Physics and Engineering, The Christie NHS Foundation Trust, Manchester (United Kingdom); Faculty of Medical and Human Sciences, Manchester Academic Health Sciences Centre, University of Manchester, Manchester (United Kingdom)

2013-12-01

54

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

PubMed

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. PMID:21925275

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

2012-02-01

55

WIDE-FIELD ASTRONOMICAL MULTISCALE CAMERAS  

SciTech Connect

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.

Marks, Daniel L.; Brady, David J., E-mail: dbrady@ee.duke.edu [Department of Electrical and Computer Engineering and Fitzpatrick Institute for Photonics, Box 90291, Duke University, Durham, NC 27708 (United States)

2013-05-15

56

Wide Field Surveys and Astronomical Discovery Space  

E-print Network

I review the status of science with wide field surveys. For many decades surveys have been the backbone of astronomy, and the main engine of discovery, as we have mapped the sky at every possible wavelength. Surveys are an efficient use of resources. They are important as a fundamental resource; to map intrinsically large structures; to gain the necessary statistics to address some problems; and to find very rare objects. I summarise major recent wide field surveys - 2MASS, SDSS, 2dfGRS, and UKIDSS - and look at examples of the exciting science they have produced, covering the structure of the Milky Way, the measurement of cosmological parameters, the creation of a new field studying substellar objects, and the ionisation history of the Universe. I then look briefly at upcoming projects in the optical-IR survey arena - VISTA, PanSTARRS, WISE, and LSST. Finally I ask, now we have opened up essentially all wavelength windows, whether the exploration of survey discovery space is ended. I examine other possible axes of discovery space, and find them mostly to be too expensive to explore or otherwise unfruitful, with two exceptions : the first is the time axis, which we have only just begun to explore properly; and the second is the possibility of neutrino astrophysics.

A. Lawrence

2007-04-05

57

Wide Field Surveys and Astronomical Discovery Space  

E-print Network

I review the status of science with wide field surveys. For many decades surveys have been the backbone of astronomy, and the main engine of discovery, as we have mapped the sky at every possible wavelength. Surveys are an efficient use of resources. They are important as a fundamental resource; to map intrinsically large structures; to gain the necessary statistics to address some problems; and to find very rare objects. I summarise major recent wide field surveys - 2MASS, SDSS, 2dfGRS, and UKIDSS - and look at examples of the exciting science they have produced, covering the structure of the Milky Way, the measurement of cosmological parameters, the creation of a new field studying substellar objects, and the ionisation history of the Universe. I then look briefly at upcoming projects in the optical-IR survey arena - VISTA, PanSTARRS, WISE, and LSST. Finally I ask, now we have opened up essentially all wavelength windows, whether the exploration of survey discovery space is ended. I examine other possible a...

Lawrence, A

2007-01-01

58

Narrowband Ultraviolet Imaging Wide Field Survey  

NASA Astrophysics Data System (ADS)

We present maps obtained from the second sounding rocket flight of the NUVIEWS survey. The NUVIEWS (Narrowband Ultraviolet Imaging Experiment for Wide Field Surveys) payload is designed to map diffuse CIV emission (155 nm), H2 fluorescence ( ˜160 nm) and far-UV continuum (140-180 nm), covering a large portion of the sky with good sensitivity on degree scales. The experiment consists of four co-aligned, wide-field (30o x 20o) self-filtering telescopes with 7-10 nm bandpasses centered on 145, 155, 161, and 176 nm. The three-mirror telescope design and microchannel-plate detector with two-dimensional readout provide good imaging ( ˜ 5') for point-source subtraction. The NUVIEWS instrument was refurbished after the first flight to enhance QE and reduce scattered light. The improved instrument was flown on June 11th, 2002 and observed approximately 40% of the sky above the horizon. We review the instrument flight performance, present skymaps for each waveband and discuss initial results. We also describe plans for future flights of NUVIEWS. The authors gratefully acknowledge support from NASA NAG5-5052/NAG5-5053.

McLean, R.; Martin, C.; Schiminovich, D.; Friedman, P. G.; Morrissey, P.; Kaye, S.

2002-12-01

59

Cn2 and wind profiler method to quantify the frozen flow decay using wide-field laser guide stars adaptive optics  

E-print Network

We use spatio-temporal cross-correlations of slopes from five Shack-Hartmann wavefront sensors to analyse the temporal evolution of the atmospheric turbulence layers at different altitudes. The focus is on the verification of the frozen flow assumption. The data is coming from the Gemini South Multi-Conjugate Adaptive Optics System (GeMS). First, the Cn2 and wind profiling technique is presented. This method provides useful information for the AO system operation such as the number of existing turbulence layers, their associated velocities, altitudes and strengths and also a mechanism to estimate the dome seeing contribution to the total turbulence. Next, by identifying the turbulence layers we show that it is possible to estimate the rate of decay in time of the correlation among turbulence measurements. We reduce on-sky data obtained during 2011, 2012 and 2013 campaigns and the first results suggest that the rate of temporal de-correlation can be expressed in terms of a single parameter that is independent ...

Guesalaga, Andrés; Cortes, Angela; Béchet, Clémentine; Guzmán, Dani

2014-01-01

60

Wide-field adaptive optics performance in cosmological deep fields for multi-object spectroscopy with the European Extremely Large Telescope  

E-print Network

A multi-object spectrograph on the forthcoming European Extremely Large Telescope will be required to operate with good sky coverage. Many of the interesting deep cosmological fields were deliberately chosen to be free of bright foreground stars, and therefore are potentially challenging for adaptive optics (AO) systems. Here we investigate multi-object AO performance using sub-fields chosen at random from within the Great Observatories Origins Deep Survey (GOODS)-S field, which is the worst case scenario for five deep fields used extensively in studies of high-redshift galaxies. Our AO system model is based on that of the proposed MOSAIC instrument but our findings are equally applicable to plans for multi-object spectroscopy on any of the planned Extremely Large Telescopes. Potential guide stars within these sub-fields are identified and used for simulations of AO correction. We achieve ensquared energies within 75~mas of between 25-35\\% depending on the sub-field, which is sufficient to probe sub-kpc scale...

Basden, Alastair; Morris, Tim

2014-01-01

61

Imaging spectrometer wide field catadioptric design  

DOEpatents

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.

Chrisp; Michael P. (Danville, CA)

2008-08-19

62

Stereoscopic wide field of view imaging system  

NASA Technical Reports Server (NTRS)

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.

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

2011-01-01

63

Fiber Optics: A Bright Future.  

ERIC Educational Resources Information Center

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)

Rice, James, Jr.

1980-01-01

64

Semiconductor optical amplifiers for future optical networks  

Microsoft Academic Search

This work describes the principal applications of SOAs in optical communication systems. They can be classified into three areas: (a) postamplifier or booster amplifier to increase transmitter laser power, (b) in-line amplifier to compensate for fiber and other transmission losses in medium and long-haul links and (c) preamplifier to improve receiver sensitivity. SOAs are used in both linear and nonlinear

A. Sharaiha

2004-01-01

65

Computational corrections for three-dimensional wide field fluorescence microscopy  

NASA Astrophysics Data System (ADS)

Microscopy is a key means of analyzing biological activity and structures, covering a level accessible by few other approaches. Increasingly, live microscopy is being used as a unique means to study the dynamics, of structure, localization, and motion of processes to develop and test hypotheses of cellular dynamics. However, analysis of sub-micron structures within living specimens often becomes difficult or impossible as the image quality degrades with increasing depth in the sample. This degradation results from aberrations due to the specimen's refractive index properties, which alter image formation at the detector. These aberrations range from a general, depth-dependent-spherical aberration for relatively homogeneous samples, to position-dependent aberrations for more complex samples. My thesis project focuses on developing computational corrections of live specimen imaging problems encountered with widefield fluorescence microscopy. The main goal of this work is to study the imaging process for widefield microscopy and to develop improved deconvolution approaches based-on-the information gathered. A significant part of this work has been to develop an improved description of an optical microscope, based on techniques developed for astronomy. My project had been subdivided into the following specific steps for further discussion below: (1) Creation of a compact and modular description of the wide field microscope system using phase retrieval; (2) Development and use of depth dependent deconvolution approaches to correct for aberrations from a general sample refractive index mismatch; and (3) estimation of spatially varying PSFs by using ray tracing techniques for the future application in image deconvolution of optically complex samples.

Hanser, Bridget Martha

2003-10-01

66

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

NASA Technical Reports Server (NTRS)

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.

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

2012-01-01

67

Wide-field spatio-spectral interferometry for far-infrared space applications: A progress report  

NASA Astrophysics Data System (ADS)

The NASA Astrophysics Roadmap Committee adopted the far-IR community’s vision and recommended far-IR interferometry as a needed capability in the 15 - 30 year time frame. The three major enabling technologies for such a mission are low-noise, high-speed detectors in small arrays; a demonstrated capability to cool optical system components to 4 K and focal planes to tens of mK with cryo-coolers; and the spatio-spectral interferometry (“double Fourier”) technique through which wide-field integral field spectroscopic data are derived from interferometric measurements. This paper reports on the current status of wide-field spatio-spectral interferometry and plans for maturation of the technique to space-flight readiness. Relatively simple spatial-spectral test patterns have been observed with the Wide-Field Imaging Interferometry Testbed at NASA’s Goddard Space Flight Center, and data cubes representing the observed scenes have been constructed based on the measured interferograms. A critical future milestone is the construction of an astronomically relevant, spatially and spectrally complex scene.

Leisawitz, David; Armstrong, J. T.; Bolcar, M. R.; Lyon, R.; Maher, S. F.; Memarsadeghi, N.; Rinehart, S.; Sinukoff, E.

2014-01-01

68

Very-wide-field ultraviolet sky survey  

NASA Technical Reports Server (NTRS)

Very-wide-field photographs of the sky were taken on Spacelab 1 at 1650, 1930, and 2530 angstroms with a limiting magnitude of 9.3 at 1930 angstroms. A 1.2 by 2.4 kiloparsec ultraviolet extension of the Shapley wing of the Small Magellanic Cloud is seen in some of the photographs.

Courtes, G.; Viton, M.; Sivan, J. P.; Dechter, R.; Gary, A.

1984-01-01

69

Stellar objects identification using wide-field camera  

NASA Astrophysics Data System (ADS)

This paper deals with evaluation and processing of astronomical image data, which are obtained by a wide-field all-sky image analyzing monitoring system (WILLIAM). The WILLIAM is an additional experimental camera for project MAIA equipped with wide field lens. The system can detect stellar objects as faint as 6th magnitude. Acquired image data are processed by an algorithm for stellar object detection and identification which is based on coordinates transfer function. Cartesian coordinates at the image data are transformed to horizontal coordinate system. This coordinate system allows searching in astronomical catalogues of stellar objects. This paper presents the components of WILLIAM, its measured electro-optical characteristics and some results of identification.

Janout, Petr; Páta, Petr; Bedná?, Jan; Anisimova, Elena; Blažek, Martin; Skala, Petr

2015-01-01

70

Rozhen Observatory wide-field plate archives  

NASA Astrophysics Data System (ADS)

This paper provides an overview of the wide-field (>10) plate archives at disposal in the Institute of Astronomy and National Astronomical Observatory Rozhen of the Bulgarian Academy of Sciences. The plates with total number 10093 are obtained in the period November 1978 - February 1998 with the 2 m RCC telescope and 50/70/172 cm Schmidt telescope. The available plate catalogues are upgraded with new information, as well as with link to the digitized logbooks (in JPEG file format). The digitization with high quality EPSON flatbed scanners of the available 2 m RCC telescope plates (with low resolution in JPEG, and with high resolution in standardized FITS file format) is accomplished. The digitization of the available 50/70/172 cm Schmidt telescope plates is running. The low resolution images of the scanned Rozhen plates are included in the Wide-Field Plate Database (http://wfpdb.org) and accessible online.

Tsvetkova, K.; Tsvetkov, M.

2013-01-01

71

The Wide-Field Infrared Explorer  

NASA Technical Reports Server (NTRS)

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.

Schember, Helene; Hacking, Perry

1993-01-01

72

Wide-field microscopy using microcamera arrays  

NASA Astrophysics Data System (ADS)

A microcamera is a relay lens paired with image sensors. Microcameras are grouped into arrays to relay overlapping views of a single large surface to the sensors to form a continuous synthetic image. The imaged surface may be curved or irregular as each camera may independently be dynamically focused to a different depth. Microcamera arrays are akin to microprocessors in supercomputers in that both join individual processors by an optoelectronic routing fabric to increase capacity and performance. A microcamera may image ten or more megapixels and grouped into an array of several hundred, as has already been demonstrated by the DARPA AWARE Wide-Field program with multiscale gigapixel photography. We adapt gigapixel microcamera array architectures to wide-field microscopy of irregularly shaped surfaces to greatly increase area imaging over 1000 square millimeters at resolutions of 3 microns or better in a single snapshot. The system includes a novel relay design, a sensor electronics package, and a FPGA-based networking fabric. Biomedical applications of this include screening for skin lesions, wide-field and resolution-agile microsurgical imaging, and microscopic cytometry of millions of cells performed in situ.

Marks, Daniel L.; Youn, Seo Ho; Son, Hui S.; Kim, Jungsang; Brady, David J.

2013-02-01

73

The wide field imager instrument for Athena  

NASA Astrophysics Data System (ADS)

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 ASIC allows readout in full frame mode and window mode as well by addressing selectively arbitrary sub-areas of the sensor allowing time resolution in the order of 10 ?s. The further detector electronics has mainly the following tasks: digitization, pre-processing and telemetry of event data as well as supply and control of the detector system. Although the sensor will already be equipped with an on-chip light blocking filter, a filter wheel is necessary to provide an additional external filter, an on-board calibration source, an open position for outgassing, and a closed position for protection of the sensor. The sensor concept provides high quantum efficiency over the entire energy band and we intend to keep the instrumental background as low as possible by designing a graded Z-shield around the sensor. All these properties make the WFI a very powerful survey instrument, significantly surpassing currently existing observatories and in addition allow high-time resolution of the brightest X-ray sources with low pile-up and high efficiency. This manuscript will summarize the current instrument concept and design, the status of the technology development, and the envisaged baseline performance.

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

2014-07-01

74

Wide Field Camera 3 Accommodations for HST Robotics Servicing Mission  

NASA Technical Reports Server (NTRS)

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.

Ginyard, Amani

2005-01-01

75

THE SPITZER DEEP, WIDE-FIELD SURVEY  

SciTech Connect

The Spitzer Deep, Wide-Field Survey (SDWFS) is a four-epoch infrared survey of 10 deg.{sup 2} in the Booetes field of the NOAO Deep Wide-Field Survey using the IRAC instrument on the Spitzer Space Telescope. SDWFS, a Spitzer Cycle 4 Legacy project, occupies a unique position in the area-depth survey space defined by other Spitzer surveys. The four epochs that make up SDWFS permit-for the first time-the selection of infrared-variable and high proper motion objects over a wide field on timescales of years. Because of its large survey volume, SDWFS is sensitive to galaxies out to z {approx} 3 with relatively little impact from cosmic variance for all but the richest systems. The SDWFS data sets will thus be especially useful for characterizing galaxy evolution beyond z {approx} 1.5. This paper explains the SDWFS observing strategy and data processing, presents the SDWFS mosaics and source catalogs, and discusses some early scientific findings. The publicly released, full-depth catalogs contain 6.78, 5.23, 1.20, and 0.96 x 10{sup 5} distinct sources detected to the average 5{sigma}, 4''-diameter, aperture-corrected limits of 19.77, 18.83, 16.50, and 15.82 Vega mag at 3.6, 4.5, 5.8, and 8.0 {mu}m, respectively. The SDWFS number counts and color-color distribution are consistent with other, earlier Spitzer surveys. At the 6 minute integration time of the SDWFS IRAC imaging, >50% of isolated Faint Images of the Radio Sky at Twenty cm radio sources and >80% of on-axis XBooetes sources are detected out to 8.0 {mu}m. Finally, we present the four highest proper motion IRAC-selected sources identified from the multi-epoch imaging, two of which are likely field brown dwarfs of mid-T spectral class.

Ashby, M. L. N.; Brodwin, M. [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States); Stern, D.; Griffith, R.; Eisenhardt, P.; Gorjian, V. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Kozlowski, S.; Kochanek, C. S. [Department of Astronomy, The Ohio State University, Columbus, OH 43210 (United States); Bock, J. J.; Borys, C. [California Institute of Technology, Pasadena, CA 91125 (United States); Brand, K.; Grogin, N. A. [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Brown, M. J. I. [School of Physics, Monash University, Clayton 3800, Victoria (Australia); Cool, R. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Cooray, A. [University of California, Irvine, CA 92697 (United States); Croft, S. [University of California, Berkeley, CA 94720 (United States); Dey, A. [NOAO, 950 N. Cherry Ave., Tucson, AZ 85719 (United States); Eisenstein, D. [Steward Observatory, Tucson, AZ 85721 (United States); Gonzalez, A. H. [Department of Astronomy, University of Florida, Gainesville, FL 32611 (United States); Ivison, R. J. [UK Astronomy Technology Centre, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom)], E-mail: mashby@cfa.harvard.edu (and others)

2009-08-10

76

WISE: Wide-field Infrared Survey Explorer  

NSDL National Science Digital Library

This University of California-Berkeley website discusses the goal of the Wide-field Infrared Survey Explorer (WISE) to "map the sky in infrared light, searching for the nearest and coolest stars, the origins of stellar and planetary systems, and the most luminous galaxies in the Universe." After reading an overview of the mission, users can find out about the science behind the mission including WISE's part in studying brown dwarfs. Professional astronomers can examine technical information about the spacecraft, its instrumentation, and data analysis. Educators and students can find classroom activities, interesting images, and informative movies and simulations.

77

Wide Field Imaging: Fourier and Fresnel  

NASA Astrophysics Data System (ADS)

Wide field imaging with low frequency synthesis arrays is limited by a number of troublesome effects. First amongst these is the ``non-coplanar baselines'' distortion whereby the integral relationship between sky brightness and measured visibility function is not a simple Fourier transform. A piece wise approximation to the integrals can be used and forms the basis of the facet approaches used for the last 15 years. These approaches are difficult to program and perform relatively poorly. We have developed a novel, high performance algorithm based upon convolution of the visibility samples with a Fresnel kernel. We interpret the Fresnel kernel as being required to propagate the electric field to a common reference plane. The role of Fresnel diffraction in radio inteferometry seems to have been unrecognized previously.

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

2005-12-01

78

PSF modelling for very wide-field CCD astronomy  

NASA Astrophysics Data System (ADS)

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.

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.; ?arnecki, A. F.

2013-03-01

79

Metrology systems of Hobby-Eberly Telescope wide field upgrade  

NASA Astrophysics Data System (ADS)

The Hobby-Eberly Telescope (HET) Wide-Field Upgrade (WFU) will be equipped with new closed-loop metrology systems to actively control the optical alignment of the new four-mirror Wide-Field Corrector (WFC) as it tracks sidereal motion with respect to the fixed primary mirror. These systems include a tip/tilt camera (TTCam), distance measuring interferometers (DMI), guide probes (GP), and wavefront sensors (WFS). While the TTCam and DMIs are to monitor the mechanical alignment of the WFC, the WFSs and GPs will produce direct measurement of the optical alignment of the WFC with respect to the HET primary mirror. Together, these systems provide fully redundant alignment and pointing information for the telescope, thereby keeping the WFC in focus and suppressing alignment driven field aberrations. In addition to these closed-loop metrology systems, we will have a pupil viewing camera (PVCam) and a calibration wavefront sensor (CWFS). The PVCam will be used for occasional reflectance measurement of the HET primary mirror segments in the standard R,G,B colors. The CWFS will provide the reference wavefront signal against which the other two WFS are calibrated. We describe the current snapshot of these systems and discuss lab/on-sky performance test results of the systems.

Lee, Hanshin; Hill, Gary J.; Cornell, Mark E.; Vattiat, Brian L.; Perry, Dave M.; Rafferty, Tom H.; Taylor, Trey; Hart, Michael; Rafal, Marc D.; Savage, Richard D.

2012-09-01

80

Wide-field, high-resolution Fourier ptychographic microscopy  

NASA Astrophysics Data System (ADS)

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 successful FPM 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.

Zheng, Guoan; Horstmeyer, Roarke; Yang, Changhuei

2013-09-01

81

Wide-field, high-resolution Fourier ptychographic microscopy.  

PubMed

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 ?m, a field-of-view of ~120 mm(2), 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

Zheng, Guoan; Horstmeyer, Roarke; Yang, Changhuei

2013-09-01

82

Optical coherence tomography – current and future applications  

PubMed Central

Purpose of review Optical coherence tomography (OCT) has revolutionized the clinical practice of ophthalmology. It is a noninvasive imaging technique that provides high-resolution, cross-sectional images of the retina, retinal nerve fiber layer and the optic nerve head. This review discusses the present applications of the commercially available spectral-domain OCT (SD-OCT) systems in the diagnosis and management of retinal diseases, with particular emphasis on choroidal imaging. Future directions of OCT technology and their potential clinical uses are discussed. Recent findings Analysis of the choroidal thickness in healthy eyes and disease states such as age-related macular degeneration, central serous chorioretinopathy, diabetic retinopathy and inherited retinal dystrophies has been successfully achieved using SD-OCT devices with software improvements. Future OCT innovations such as longer-wavelength OCT systems including the swept-source technology, along with Doppler OCT and en-face imaging, may improve the detection of subtle microstructural changes in chorioretinal diseases by improving imaging of the choroid. Summary Advances in OCT technology provide for better understanding of pathogenesis, improved monitoring of progression and assistance in quantifying response to treatment modalities in diseases of the posterior segment of the eye. Further improvements in both hardware and software technologies should further advance the clinician’s ability to assess and manage chorioretinal diseases. PMID:23429598

Adhi, Mehreen; Duker, Jay S.

2013-01-01

83

Wide-field Solc-type birefringent filter  

NASA Astrophysics Data System (ADS)

A 24-element wide-field Solc birefringent filter (WFSBF) has been produced and tested for the first time. WFSBF is a second unit to the 3-unit BF designed for imaging solar magnetic fields in the FeI 6173 Å spectral line. WFSBF passband full width at half maximum is 0.2 Å. The optical stage of the Solc BF is apodized. The main passband has a two-peak profile, to increase BF transmittance in spectral line wings. The neighbouring passbands at 2 Å are cut off by the first BF unit. To measure magnetic fields, a narrower passband of the third BF unit is to scan the spectral line wings in the +/-0.05Å positions, in accordance with two-peak positions of the Solc filter profile. The wide field of view (FOV) of the Solc filter was reached with composite birefringent stages of 24 positive artificial paratellurite and 24 negative natural calcite crystals. FOV of a composite stage is eleven times larger than that of the only-calcite one. The calculated passband is compared to the experimental one. Technological aspects of the manufacture as well as devices for plate orientation are discussed.

Skomorovsky, Valery I.; Kushtal, Galina I.; Sadokhin, Valery P.

2012-09-01

84

Wide-field Fizeau imaging telescope: experimental results.  

PubMed

A nine-aperture, wide-field Fizeau imaging telescope has been built at the Lockheed-Martin Advanced Technology Center. The telescope consists of nine, 125 mm diameter collector telescopes coherently phased and combined to form a diffraction-limited image with a resolution that is consistent with the 610 mm diameter of the telescope. The phased field of view of the array is 1 murad. The measured rms wavefront error is 0.08 waves rms at 635 nm. The telescope is actively controlled to correct for tilt and phasing errors. The control sensing technique is the method known as phase diversity, which extracts wavefront information from a pair of focused and defocused images. The optical design of the telescope and typical performance results are described. PMID:16778931

Kendrick, R L; Aubrun, Jean-Noel; Bell, Ray; Benson, Robert; Benson, Larry; Brace, David; Breakwell, John; Burriesci, Larry; Byler, Eric; Camp, John; Cross, Gene; Cuneo, Peter; Dean, Peter; Digumerthi, Ramji; Duncan, Alan; Farley, John; Green, Andy; Hamilton, Howard H; Herman, Bruce; Lauraitis, Kris; de Leon, Erich; Lorell, Kenneth; Martin, Rob; Matosian, Ken; Muench, Tom; Ni, Mel; Palmer, Alice; Roseman, Dennis; Russell, Sheldon; Schweiger, Paul; Sigler, Rob; Smith, John; Stone, Richard; Stubbs, David; Swietek, Gregg; Thatcher, John; Tischhauser, C; Wong, Harvey; Zarifis, Vassilis; Gleichman, Kurt; Paxman, Rick

2006-06-20

85

Near-perfect Collimation of Wide-Field Cassegrain Telescopes  

NASA Astrophysics Data System (ADS)

I describe a simple new method for collimating a Cassegrain telescope that gives near-perfect correction over a wide field of view. This method was used to collimate the 6.5 m MMT in 2002 with remarkably good results. The first step is to point the primary mirror accurately at an object. When the M1 optical axis points exactly toward an object, it cannot contribute pointing error, coma, or anamorphic aberration to the image field. If these are present, they must come from M2. Adjusting M2 to correct both pointing error and coma yields perfect collimation, canceling off-axis anamorphic aberrations. I present an analytical basis for this method and compare it with methods that measure off-axis image aberrations directly. In most cases, the technique described here gives better results. I describe the collimation procedure we used at MMT and suggest an easier way to adapt this method to other telescopes.

Blanco, Daniel R.

2012-01-01

86

Wide-field surveys from the SNAP mission  

SciTech Connect

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.

agkim@lbl.gov

2002-07-23

87

Thermal design of the Wide Field/Planetary Camera  

NASA Technical Reports Server (NTRS)

The Wide Field/Planetary Camera is an imaging system developed by the Jet Propulsion Laboratory for the NASA Hubble Space Telescope currently scheduled to be launched in December 1989 aboard the space shuttle. The temperature control design of the instrument utilizes multilayered insulation, electric resistance heaters, aluminum/ammonia heat pipes, thermoelectric coolers, temperature control coatings, and space radiators. A feedback control system maintains stable sensor temperatures. Thermal capacitance maintains stable optics and electronics temperatures during transient conditions. Schedule slips and launch delays have allowed extensive thermal testing of the instrument. Six instrument thermal vacuum tests and a spacecraft thermal vacuum test were performed. Several modifications have been made to the instrument to correct icing and contamination problems that have been discovered during thermal vacuum testing. This paper describes the thermal design, last instrument thermal vacuum test, results, and thermal model correlation.

Garcia, R. D.; Jones, J. A.; Stultz, J. W.

1989-01-01

88

Solar Physics, Space Weather, and Wide-field X-ray Telescopes  

E-print Network

Solar Physics, Space Weather, and Wide-field X-ray Telescopes CREOL & FPCE: The College of Optics at CREOL Industrial Affiliates Day "Optics & Photonics for Space-Based and Medical Applications" April 21, 2006 #12;Abstract The sun is essentially a giant thermonuclear fusion reactor (105 x the size

Van Stryland, Eric

89

The Wide-Field Imaging Interferometry Testbed (WIIT): Recent Progress and Results  

NASA Technical Reports Server (NTRS)

Continued research with the Wide-Field Imaging Interferometry Testbed (WIIT) has achieved several important milestones. We have moved WIIT into the Advanced Interferometry and Metrology (AIM) Laboratory at Goddard, and have characterized the testbed in this well-controlled environment. The system is now completely automated and we are in the process of acquiring large data sets for analysis. In this paper, we discuss these new developments and outline our future research directions. The WIIT testbed, combined with new data analysis techniques and algorithms, provides a demonstration of the technique of wide-field interferometric imaging, a powerful tool for future space-borne interferometers.

Rinehart, Stephen A.; Frey, Bradley J.; Leisawitz, David T.; Lyon, Richard G.; Maher, Stephen F.; Martino, Anthony J.

2008-01-01

90

The Wide-Field Imaging Interferometry Testbed: Progress and Plans  

NASA Technical Reports Server (NTRS)

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.

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

2004-01-01

91

RAPID REGISTRATION FOR WIDE FIELD-OF-VIEW  

E-print Network

RAPID REGISTRATION FOR WIDE FIELD-OF-VIEW FREEHAND 3D ULTRASOUND A. H. Gee, G. M. Treece, R. W@radiol.cam.ac.uk #12;#12;Rapid Registration for Wide Field-of-View Freehand 3D Ultrasound Andrew Gee, Graham Treece Abstract A freehand scanning protocol is the only way to acquire arbitrary large volumes of 3D ultrasound

Drummond, Tom

92

How to benchmark a wide field fluorescent microscope  

E-print Network

How to benchmark a wide field fluorescent microscope Detection threshold(ms) Saturation to generate measurements that characterize a wide-field fluorescence microscope is useful to ensure nominal instrument performance. · The procedure described here benchmarks the microscope to a commercial fluorescent

93

Prototype designs for a wide-field high-resolution low-scatter image device  

Microsoft Academic Search

An optical design was done for a system having a wide field of view with diffraction limited resolution over a 5 deg by 10 deg FOV. The length of the system including a baffle was set such that the earth does not illuminate the primary mirror at an angle of 1.66 deg. The system was analyzed using APART and, with

S. R. Lange; A. W. Greynolds

1980-01-01

94

Narrowband ultraviolet imaging experiment for wide-field surveys (NUVIEWS)  

NASA Astrophysics Data System (ADS)

We are developing a rocket-borne, imaging, wide-field, survey experiment to study global interactions in the multiphase interstellar medium. The experiment will map diffuse C IV (C(superscript 3+)) (lambda) 1549, H(subscript 2) (lambda) (lambda) 1575 - 1645 Lyman band fluorescence, and dust-scattered starlight continuum ((lambda) (lambda) 1400 - 1900) emission over one quarter of the sky in a single rocket flight. Good imaging is maintained in two dimensions, permitting the direct exclusion of stars entering the field of view. The payload consists of four independent, co-aligned telescopes of identical optical construction. Three telescopes are made sensitive in a narrow band by depositing tuned all-dielectric multilayers on the mirror surfaces to achieve a so-called `self-filtering' camera. Each telescope incorporates a large-format imaging microchannel plate detector that is read out using a two- dimensional, crossed, serpentine delay line anode which we have developed. The rocket flight, scheduled for launch in 1994, will be the first flight of a two-dimensional, crossed, serpentine delay line anode.

Fleischman, Judith R.; Friedman, Peter G.; Martin, Christopher; Schiminovich, David

1993-11-01

95

Non-mydriatic, wide field, fundus video camera  

NASA Astrophysics Data System (ADS)

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.

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

2014-02-01

96

Wide field-of-view microscopy with Talbot pattern illumination  

NASA Astrophysics Data System (ADS)

Wide field-of-view (FOV) microscopy is useful for high-throughput applications because of the capability to obtain large amount of information from a single image. One way to implement a wide FOV microscope is to scan the sample with a two-dimensional focus grid. The transmission or reflection of the focal spots can then be used to reconstruct the sample image. This scheme is effectively a parallel scanning optical microscope (SOM), where the FOV depends on the area of the focus grid and the imaging resolution depends on the spot size of the foci. We use the Talbot image of a twodimensional aperture grid as the focus grid and developed a wide FOV microscope. Preliminary experimental results show the capability of our microscope to acquire wide FOV images of US air force target and MCF-7 cancer cell samples. Fluorescence images of fluorescence beads are also acquired. Because the diffraction of incident beam by the aperture grid contains complicated angular frequencies, the focal spots in Talbot pattern cannot be approximated as Gaussian beams as in conventional SOM. We characterized the focal spots in Talbot pattern and studied the evolution of the full width at half maximum (FWHM). We also simulated the SOM imaging under Talbot pattern illumination using the razor blade as the sample objects.

Wu, Jigang; Liu, Guangshuo

2012-12-01

97

MIRIS: A Compact Wide-field Infrared Space Telescope  

NASA Astrophysics Data System (ADS)

A compact infrared space telescope called MIRIS (Multi-purpose Infra-Red Imaging System) was developed by the Korea Astronomy and Space Science Institute (KASI), and launched onboard the Science and Technology Satellite-3 of Korea (STSAT-3) in 2013 November. The main mission of MIRIS is the Paschen-? emission line survey along the Galactic plane and the cosmic infrared background (CIB) observation, particularly around the north ecliptic pole region. For these missions, a wide field of view (3.67 × 3.67°) with an angular resolution of 51.6? and wavelength coverage from 0.9 ˜ 2.0 ?m have been adopted for MIRIS, having optical components consisting of a 80 mm main lens and four other lenses with F/2 focal ratio optics. The opto-mechanical system was carefully designed to minimize any effects from shock during the launch process and thermal variation. Also, the telescope was designed to use a passive cooling technique to maintain the temperature around 200 K in order to reduce thermal noise. A micro Stirling cooler was used to cool down the Teledyne PICNIC infrared array to 90 K, which was equipped in a dewar with four filters for infrared passbands of I, H, and Paschen-? and a dual-band continuum line filter. MIRIS system was integrated into the STSAT-3 as its primary payload and successfully passed required tests in the laboratory, such as thermal-vacuum, vibration, and shock tests. MIRIS is now operating in sun synchronous orbits for initial tests and has observed its first images successfully.

Han, Wonyong; Lee, Dae-Hee; Jeong, Woong-Seob; Park, Youngsik; Moon, Bongkon; Park, Sung-Joon; Pyo, Jeonghyun; Kim, Il-Joong; Park, Won-Kee; Lee, Dukhang; Seon, Kwang-Il; Nam, Uk-Won; Cha, Sang-Mok; Park, Kwijong; Park, Jang-Hyun; Yuk, In-Soo; Hee Ree, Chang; Jin, Ho; Choel Yang, Sun; Park, Hong-Young; Shin, Goo-Hwan; Seo, Joung-Ki; Rhee, Seung-Wu; Park, Jong-Oh; Mok Lee, Hyung; Murakami, Hiroshi; Matsumoto, Toshio

2014-11-01

98

Depth resolved wide field illumination for biomedical imaging and fabrication  

E-print Network

Nonlinear microscopic imaging is relatively slow due to the sequential nature of raster scanning. Recently, this limitation was overcome by developing a 3D-resolved wide-field two-photon microscope based on the concept of ...

So, Peter T. C.

99

Automated Classification of Periodic Variable Stars Detected by the Wide-field Infrared Survey Explorer  

NASA Astrophysics Data System (ADS)

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.

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

2014-07-01

100

Wide-field holography of Compact Array antennae at 1.4 GHz  

NASA Astrophysics Data System (ADS)

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.

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

2006-08-01

101

Leveraging Optical Technology in Future Bus-based Chip Multiprocessors  

Microsoft Academic Search

Although silicon optical technology is still in its formative stages, and the more near-term application is chip-to-chip communication, rapid advances have been made in the de- velopment of on-chip optical interconnects. In this paper, we investigate the integration of CMOS-compatible optical technology to on-chip cache-coherent buses in future CMPs. While not exhaustive, our investigation yields a hierarchi- cal opto-electrical system

Nevin Kirman; Meyrem Kirman; Rajeev K. Dokania; Jose F. Martinez; Alyssa B. Apsel; Matthew A. Watkins; David H. Albonesi

2006-01-01

102

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

NASA Astrophysics Data System (ADS)

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 ?/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.

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

2010-07-01

103

Electro-optic polymer integrated optic devices and future applications  

Microsoft Academic Search

Recent developments in electro-optic polymer materials and devices have led to new opportunities for integrated optic devices in numerous applications. The results of numerous tests have indicated that polymer materials have many properties that are suitable for use in high-speed communications systems, various sensor systems, and space applications. These result coupled with recent advances in device and material technology will

James H. Bechtel; James H. Menders; De Yu Zang

2003-01-01

104

Electro-Optic Polymer Integrated Optic Devices and Future Applications  

Microsoft Academic Search

Recent developments in electro-optic polymer materials and devices have led to new opportunities for integrated optic devices in numerous applications. The results of numerous tests have indicated that polymer materials have many properties that are suitable for use in high-speed communications systems, various sensor systems, and space applications. These results, coupled with recent advances in device and material technology, will

James H. Bechtel

2003-01-01

105

Wide Field Imagers in Space and the Cluster Forbidden Zone  

NASA Astrophysics Data System (ADS)

The epoch from z=2.5-1.0 may well be the epoch of cluster formation. Today, studying this epoch from the perspective of clusters is nearly impossible. We study clusters to investigate cosmological parameters, the assembly of large scale structure, the chemical enrichment history of the universe, and the effects of environment and birth place on the evolution of galaxies. But clusters are rare objects; cluster-finding requires deep imaging of large areas of sky (the most massive clusters have a space density of only 10-9 h503 Mpc-3). Clusters, because of the effects of cosmological diminuition on their X-ray surface brightness at X-ray wavelengths, and the K-correction effects of their member galaxies (predominately ellipticals in the cores), are very difficult to detect in the X-rays or at optical wavelengths at z>1-1.5. A wide-field survey with the sensitivity of HAB ~ 27 would enable us to detect incipient elliptical galaxies 2 mags below present-day L* out to z ~ 2-2.5. A 1,000 deg2 cluster survey including ~ 2000 of the most massive clusters would open cluster studies to previously unaccessible territory: the epoch from z=1-2.5. Clusters have not evolved very much over the epoch we can now study them, z=0-1. However, from theoretical expectations regarding the formation of large scale structure, we expect clusters to be evolving very rapidly in the epoch z=2.5-1.0, the era of cluster formation. Finding and studying clusters in this redshift range would open an important window on cluster and structure evolution.

Donahue, M. E.

2001-12-01

106

A wide-field survey for high-redshift quasars  

NASA Astrophysics Data System (ADS)

The present thesis reports the results from the Hawaii Quasar and T dwarf survey (HQT survey), which is a wide-field optical imaging survey conducted with Subaru/Suprime-Cam. The HQT survey was designed to search for low- luminosity quasars ( M 1450 < -22.5) at high-redshift ( z > 5.7) as well as T dwarfs, both of which are selected by their very red optical I -- z ' colors. We developed a new color selection technique using a narrowband NB 816 filter in order to break a well-known color degeneracy between quasars and foreground M and L dwarfs. The follow-up Keck/DEIMOS spectroscopy and near-IR imaging with various instruments on Mauna Kea have demonstrated the effectiveness of our technique, and have successfully revealed six faint T dwarfs ( J < 20). These dwarfs are among the most distant spectroscopically known (60 - 170 pc) and they provide an indirect support for the high binary fraction at L/ T transition. The non-detection of z > 5.7 quasars in our survey is consistent with the present picture of the cosmic reionization in which quasars are negligible contributor to the cosmic reionization. With our survey area coverage (9.3 deg 2 ) and depths ( Z AB < 23.3), we were able to set strong constraints on the faint-end slope of the quasar luminosity function. Majority of our candidate quasars turned out to be strong emission line galaxies at z < 1, whose large equivalent widths and low metal contents suggest they are very young systems which have just undergone starbursts within a few Myrs. In order to systematically search for these Ultra-Strong Emission Line galaxies (USELs), we used narrowband selected samples from Hu's ultra-deep multiwavelength data. The followup Keck/DEIMOS spectra have revealed their high star formation density (5-10% of UV measurements at z = 0-1), which is a significant contribution at a epoch when cosmic star formation is in its peak. Many of the USELs show [OIII]l4363 auroral lines and about a dozen satisfy the criteria for eXtremely Metal Poor Galaxies (XMPGs). Our XMPGs are the most distant known today. Our high yield rate of XMPGs suggests that narrowband method is powerful in finding such populations. Strikingly, a few of our XMPGs have metallities close to the most metal-poor galaxy. Our discovery indicates that galaxies are still forming in relatively chemically pristine sites at z ~ 1

Kakazu, Yuko K. M.

2008-02-01

107

A Precision Metrology System for the Hubble Space Telescope Wide Field Camera 3 Instrument  

NASA Technical Reports Server (NTRS)

The Wide Field Camera 3 (WFC3) instrument for the Hubble Space Telescope (HST) will replace the current Wide Field and Planetary Camera 2 (WFPC2). By providing higher throughput and sensitivity than WFPC2, and operating from the near-IR to the near-UV, WFC3 will once again bring the pefiormance of HST above that from ground-based observatories. Crucial to the integration of the WFC3 optical bench is a pair of 2-axis cathetometers used to view targets which cannot be seen by other means when the bench is loaded into its enclosure. The setup and calibration of these cathetometers is described, along with results from a comparison of the cathetometer system with other metrology techniques. Finally, the use of the cathetometers on the flight optical bench and measurement results are given.

Toland, Ronald W.

2003-01-01

108

Wide-Field Imaging Interferometry Spatial-Spectral Image Synthesis Algorithms  

NASA Technical Reports Server (NTRS)

Developed is an algorithmic approach for wide field of view interferometric spatial-spectral image synthesis. The data collected from the interferometer consists of a set of double-Fourier image data cubes, one cube per baseline. These cubes are each three-dimensional consisting of arrays of two-dimensional detector counts versus delay line position. For each baseline a moving delay line allows collection of a large set of interferograms over the 2D wide field detector grid; one sampled interferogram per detector pixel per baseline. This aggregate set of interferograms, is algorithmically processed to construct a single spatial-spectral cube with angular resolution approaching the ratio of the wavelength to longest baseline. The wide field imaging is accomplished by insuring that the range of motion of the delay line encompasses the zero optical path difference fringe for each detector pixel in the desired field-of-view. Each baseline cube is incoherent relative to all other baseline cubes and thus has only phase information relative to itself. This lost phase information is recovered by having point, or otherwise known, sources within the field-of-view. The reference source phase is known and utilized as a constraint to recover the coherent phase relation between the baseline cubes and is key to the image synthesis. Described will be the mathematical formalism, with phase referencing and results will be shown using data collected from NASA/GSFC Wide-Field Imaging Interferometry Testbed (WIIT).

Lyon, Richard G.; Leisawitz, David T.; Rinehart, Stephen A.; Memarsadeghi, Nargess; Sinukoff, Evan J.

2012-01-01

109

High-resolution wide-field Raman imaging through a fiber bundle  

NASA Astrophysics Data System (ADS)

Wide-field Raman imaging with a spatial resolution of a few micrometers is demonstrated using bundles of thousands of hexagonally packed optical fibers. Raman images are synthesized pixel by pixel, by sequentially coupling the laser pump into individual fibers of the bundle with a galvanometric scanner and collecting the Raman response from the laser-excited region of the sample within the entire aperture of the distal end of the same fiber bundle.

Doronina-Amitonova, Lyubov V.; Fedotov, Il'ya V.; Fedotov, Andrey B.; Zheltikov, Aleksei M.

2013-04-01

110

The Garching-Bonn Deep Survey (GaBoDS) Wide-Field-Imaging Reduction Pipeline  

E-print Network

We introduce our publicly available Wide-Field-Imaging reduction pipeline THELI. The procedures applied for the efficient pre-reduction and astrometric calibration are presented. A special emphasis is put on the methods applied to the photometric calibration. As a test case the reduction of optical data from the ESO Deep Public Survey including the WFI-GOODS data is described. The end-products of this project are now available via the ESO archive Advanced Data Products section.

H. Hildebrandt; T. Erben; M. Schirmer; J. P. Dietrich; P. Schneider

2007-05-03

111

Low Mass Density Wide Field Far-IR/Submillimeter Telescope Systems  

E-print Network

Fundamentally new technology is described for constructing low areal mass density (1kg/m^2), high precision (< 10micron RMS) reflectors scalable to large apertures (10 to 20 meters) for use as the primary element of a telescope system. A large reduction in mass is achieved by minimizing the mass of the reflective surface using a high reflectivity metallic membrane. A wide field diffraction limited telescope system can be constructed using the primary reflector in conjunction with secondary and tertiary optics.

Mark Dragovan

2000-01-13

112

Deepest Wide-Field Colour Image in the Southern Sky  

NASA Astrophysics Data System (ADS)

LA SILLA CAMERA OBSERVES CHANDRA DEEP FIELD SOUTH ESO PR Photo 02a/03 ESO PR Photo 02a/03 [Preview - JPEG: 400 x 437 pix - 95k] [Normal - JPEG: 800 x 873 pix - 904k] [HiRes - JPEG: 4000 x 4366 pix - 23.1M] Caption : PR Photo 02a/03 shows a three-colour composite image of the Chandra Deep Field South (CDF-S) , obtained with the Wide Field Imager (WFI) camera on the 2.2-m MPG/ESO telescope at the ESO La Silla Observatory (Chile). It was produced by the combination of about 450 images with a total exposure time of nearly 50 hours. The field measures 36 x 34 arcmin 2 ; North is up and East is left. Technical information is available below. The combined efforts of three European teams of astronomers, targeting the same sky field in the southern constellation Fornax (The Oven) have enabled them to construct a very deep, true-colour image - opening an exceptionally clear view towards the distant universe . The image ( PR Photo 02a/03 ) covers an area somewhat larger than the full moon. It displays more than 100,000 galaxies, several thousand stars and hundreds of quasars. It is based on images with a total exposure time of nearly 50 hours, collected under good observing conditions with the Wide Field Imager (WFI) on the MPG/ESO 2.2m telescope at the ESO La Silla Observatory (Chile) - many of them extracted from the ESO Science Data Archive . The position of this southern sky field was chosen by Riccardo Giacconi (Nobel Laureate in Physics 2002) at a time when he was Director General of ESO, together with Piero Rosati (ESO). It was selected as a sky region towards which the NASA Chandra X-ray satellite observatory , launched in July 1999, would be pointed while carrying out a very long exposure (lasting a total of 1 million seconds, or 278 hours) in order to detect the faintest possible X-ray sources. The field is now known as the Chandra Deep Field South (CDF-S) . The new WFI photo of CDF-S does not reach quite as deep as the available images of the "Hubble Deep Fields" (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 January 1999 when the WFI instrument was first installed (cf. ESO PR 02/99

2003-01-01

113

Wide-Field-of-View Polarization Interference Imaging Spectrometer  

Microsoft Academic Search

A wide-field-of-view polarization interference imaging spectrometer (WPIIS) based on a modified Savart polariscope, without moving parts, and with a narrow slit has been designed. The primary feature of this device is for use with a large angle of incidence, and the target image as well as the interferogram can be obtained at the same time in the spatial domain and

Chunmin Zhang; Baochang Zhao; Bin Xiangli

2004-01-01

114

Michelson wide-field stellar interferometry: principles and experimental verification  

E-print Network

is that the OPD is corrected for the pointing direction of the telescope. A wide field of view is important plane of each telescope in the array, allowing for simultaneous correction of the differential delay interferometry1 consists of using two or more telescopes that collect light from a distant object to produce

115

Update on the Wide-Field Infrared Survey Explorer (WISE)  

Microsoft Academic Search

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.

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

2006-01-01

116

A Precision Metrology System for the Hubble Space Telescope Wide Field Camera 3 Instrument  

NASA Technical Reports Server (NTRS)

The Wide Field Camera 3 (WFC3) instrument for the Hubble Space Telescope (HST) will replace the current Wide Field and Planetary Camera 2 (WFPC2). By providing higher throughput and sensitivity than WFPC2, and operating from the near-IR to the near-UV, WFC3 will once again bring the performance of HST above that from ground-based observatories. Crucial to the integration of the WFC3 optical bench is a pair of 2-axis cathetometers used to view targets which cannot be seen by other means when the bench is loaded into its enclosure. The setup and calibration of these cathetometers is described, along with results from a comparison of the cathetometer system with other metrology techniques.

Toland, Ronald W.

2003-01-01

117

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

NASA Astrophysics Data System (ADS)

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° ields 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.

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

2014-07-01

118

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

NASA Technical Reports Server (NTRS)

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.

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

119

Wide-field turbulence imaging with beam emission spectroscopy  

SciTech Connect

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 8 x 8 grid of discrete channels that image an approximately 7 x 9 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 8 x 8 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 < r/a < 1, including the core ({tilde n}n < 1% ), pedestal, and scrape-off-layer. The resulting time-resolved visualizations of turbulence and flows provide critical data on turbulence dynamics.

McKee, G. R. [University of Wisconsin, Madison; Fonck, R. J. [University of Wisconsin, Madison; Shafer, M.W. [Oak Ridge National Laboratory (ORNL); Uzon-Kaymak, I. U. [University of Wisconsin, Madison

2010-01-01

120

Wide-field turbulence imaging with beam emission spectroscopy  

SciTech Connect

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

McKee, G. R.; Fonck, R. J.; Uzun-Kaymak, I. U.; Yan, Z. [University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); Shafer, M. W. [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)

2010-10-15

121

Michelson wide-field stellar interferometry: principles and experimental verification.  

PubMed

A new interferometric technique for Michelson wide-field interferometry is presented that consists of a Michelson pupil-plane combination scheme in which a wide field of view can be achieved in one shot. This technique uses a stair-shaped mirror in the intermediate image plane of each telescope in the array, allowing for simultaneous correction of the differential delay for the on-axis and off-axis image positions. Experimental results in a laboratory setup show that it is possible to recover the fringes of on-axis and off-axis stars with an angular separation of 1 arc min simultaneously and with a similar contrast. This new technique represents a considerable extension of the field of view of an interferometer without the need for extra observation time. PMID:15717821

Montilla, I; Pereira, S F; Braat, J J M

2005-01-20

122

Mitigating fluorescence spectral overlap in wide-field endoscopic imaging  

NASA Astrophysics Data System (ADS)

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.

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

2013-08-01

123

In-Flight Performance of Wide Field Camera 3  

NASA Technical Reports Server (NTRS)

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.

Kimble, Randy

2010-01-01

124

Wide-field Fizeau imaging telescope: experimental results  

Microsoft Academic Search

A nine-aperture, wide-field Fizeau imaging telescope has been built at the Lockheed-Martin Advanced Technology Center. The telescope consists of nine, 125 mm diameter collector telescopes coherently phased and combined to form a diffraction-limited image with a resolution that is consistent with the 610 mm diameter of the telescope. The phased field of view of the array is 1 murad. The

R. L. Kendrick; Jean-Noel Aubrun; Ray Bell; Robert Benson; Larry Benson; David Brace; John Breakwell; Larry Burriesci; Eric Byler; John Camp; Gene Cross; Peter Cuneo; Peter Dean; Ramji Digumerthi; Alan Duncan; John Farley; Andy Green; Howard H. Hamilton; Bruce Herman; Kris Lauraitis; Erich de Leon; Kenneth Lorell; Rob Martin; Ken Matosian; Tom Muench; Mel Ni; Alice Palmer; Dennis Roseman; Sheldon Russell; Paul Schweiger; Rob Sigler; John Smith; Richard Stone; David Stubbs; Gregg Swietek; John Thatcher; C. Tischhauser; Harvey Wong; Vassilis Zarifis; Kurt Gleichman; Rick Paxman

2006-01-01

125

Metal multilayer mirrors for EUV wide field telescopes  

Microsoft Academic Search

Metal multilayer mirrors have been designed for the ALEXIS satellite, which is to carry six wide field telescopes to perform an all-sky survey in three or four narrow wavelength bands in the EUV. Comprised of alternating layers of molybdenum and silicon, the mirrors are optimized to provide maximum reflectivity at angles from 11.5 to 17\\/degree\\/ off normal incidence and at

B. W. Smith; J. J. Bloch; D. Roussel-Dupre

1989-01-01

126

Calibration Status and Results for Wide Field Camera 3  

Microsoft Academic Search

Wide Field Camera 3 (WFC3) is a general-purpose imager in develop- ment for installation in HST Servicing Mission 4 (SM4). Covering the wavelength range of 200-1700 nm in two observing channels, WFC3 offers powerful new capabil- ities, particularly in the near-ultraviolet and near-infrared bands. During 2004, the instrument was integrated and underwent a substantial suite of end-to-end charac- terization and

Randy A. Kimble

127

Present and Future Needs of Free-Space Optical Interconnects  

Microsoft Academic Search

Over the last decade significant progress in optoelectronic devices and their integration techniques have made Free-Space Optical Interconnects (FSOI) one of the few physical approaches that can potentially address the increasingly complex communication requirements at the board-to-board and chip-to-chip levels. In this paper, we review the recent advances made and discuss future research directions needed to bring FSOI to the

Sadik C. Esener; Philippe J. Marchand

2000-01-01

128

Design drivers for a wide-field multi-object spectrograph for the William Herschel Telescope  

E-print Network

Wide-field multi-object spectroscopy is a high priority for European astronomy over the next decade. Most 8-10m telescopes have a small field of view, making 4-m class telescopes a particularly attractive option for wide-field instruments. We present a science case and design drivers for a wide-field multi-object spectrograph (MOS) with integral field units for the 4.2-m William Herschel Telescope (WHT) on La Palma. The instrument intends to take advantage of a future prime-focus corrector and atmospheric-dispersion corrector that will deliver a field of view 2 deg in diameter, with good throughput from 370 to 1,000 nm. The science programs cluster into three groups needing three different resolving powers R: (1) high-precision radial-velocities for Gaia-related Milky Way dynamics, cosmological redshift surveys, and galaxy evolution studies (R = 5,000), (2) galaxy disk velocity dispersions (R = 10,000) and (3) high-precision stellar element abundances for Milky Way archaeology (R = 20,000). The multiplex requ...

Balcells, Marc; Carter, David; Dalton, Gavin B; Trager, Scott C; Feltzing, Sofia; Verheijen, Marc A W; Jarvis, Matt; Percival, Will; Abrams, Don C; Agocs, Tibor; Brown, Anthony G A; Cano, Diego; Evans, Chris; Helmi, Amina; Lewis, Ian J; McLure, Ross; Peletier, Reynier F; Perez-Fournon, Ismael; Sharples, Ray M; Tosh, Ian A J; Trujillo, Ignacio; Walton, Nic; Westfall, Kyle B

2010-01-01

129

Improved resolution in wide-field ultraviolet astronomical imaging  

NASA Astrophysics Data System (ADS)

Heritage wide-field ultraviolet imagers have observed large (~30°) fields-of-view, but suffer from relatively poor (~0.6°) spatial resolution. Improvements in mirror design and fabrication technology allow for a new two-mirror design that preserves a large (40°x20°) field-of-view, while improving spatial resolution by nearly a factor of ten to 0.07° while imaging onto a flat focal surface. Such an imager has uses in a number of ultraviolet astronomical applications, including plasmaspheric imaging and monitoring of the interplanetary medium.

Davis, Michael W.; Greathouse, Thomas K.; Gladstone, G. Randall

2014-07-01

130

Dwarf Irregular Galaxy Leo A. Suprime-Cam Wide-Field Stellar Photometry  

E-print Network

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 $\\sim$0.8") were obtained with Subaru Telescope equipped with Suprime-Cam mosaic camera. The wide-field ($20' \\times 24'$) photometry catalog of 38,856 objects ($V \\sim 16-26$ mag) is presented. This survey is also intended to serve as "a finding chart" for future imaging and spectroscopic observation programs of Leo A.

Stonkut?, R; Hasegawa, T; Narbutis, D; Tamura, N; Vansevi?ius, V

2014-01-01

131

Imaging without lenses: achievements and remaining challenges of wide-field on-chip microscopy  

PubMed Central

We discuss unique features of lens-free computational imaging tools and report some of their emerging results for wide-field on-chip microscopy, such as the achievement of a numerical aperture (NA) of ~0.8–0.9 across a field of view (FOV) of more than 20 mm2 or an NA of ~0.1 across a FOV of ~18 cm2, which corresponds to an image with more than 1.5 gigapixels. We also discuss the current challenges that these computational on-chip microscopes face, shedding light on their future directions and applications. PMID:22936170

Greenbaum, Alon; Luo, Wei; Su, Ting-Wei; Göröcs, Zoltán; Xue, Liang; Isikman, Serhan O; Coskun, Ahmet F; Mudanyali, Onur; Ozcan, Aydogan

2012-01-01

132

Wide-Field MAXI: soft X-ray transient monitor  

E-print Network

Wide-Field MAXI (WF-MAXI: Wide-Field Monitor of All-sky X-ray Image) is a proposed mission to detect and localize X-ray transients including electro-magnetic counterparts of gravitational-wave events such as gamma-ray bursts and supernovae etc., which are expected to be directly detected for the first time in late 2010's by the next generation gravitational telescopes such as Advanced LIGO and KAGRA. The most distinguishing characteristics of WF-MAXI are a wide energy range from 0.7 keV to 1 MeV and a large field of view (~25 % of the entire sky), which are realized by two main instruments: (i) Soft X-ray Large Solid Angle Camera (SLC) which consists of four pairs of crisscross coded aperture cameras using CCDs as one-dimensional fast-readout detectors covering 0.7 - 12 keV and (ii) Hard X-ray Monitor (HXM) which is a multi-channel array of crystal scintillators coupled with avalanche photo-diodes covering 20 keV - 1 MeV.

Arimoto, Makoto; Yatsu, Yoichi; Tomida, Hiroshi; Ueno, Shiro; Kimura, Masashi; Mihara, Tatehiro; Serino, Motoko; Morii, Mikio; Tsunemi, Hiroshi; Yoshida, Atsumasa; Sakamoto, Takanori; Kohmura, Takayoshi; Negoro, Hitoshi; Ueda, Yoshihiro; Tsuboi, Yohko; Ebisawa, Ken

2015-01-01

133

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

SciTech Connect

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.

Hudec, Rene [Astronomical Institute of Czech Academy of Science, Observatory Ondrejov, 251 65 Ondrejov (Czech Republic); Pina, Ladislav [Faculty of Nuclear Engineering, Czech Technical University, Prague (Czech Republic); Inneman, Adolf [Department of Precision Mechanics and Optics, Faculty of Mechanical Engineering, Czech Technical University, Prague (Czech Republic); Gorenstein, Paul [Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts (United States)

1998-05-16

134

Curvature wavefront sensing performance simulations for active correction of the Javalambre wide-field telescopes  

NASA Astrophysics Data System (ADS)

In order to maintain image quality during Javalambre wide field telescope operations, deformations and rigid body motions must be actively controlled to minimize optical disturbances. For JST/T250 the aberrations of the telescope will be measured with four curvature sensors at the focal plane. To correct the measured distortions, the secondary mirror position (with a hexapod support) and the camera position can be modified in a control closed loop. Multiple software tools have been developed to accomplish this goal, constituting the "Observatorio Astrofísico de Javalambre" (OAJ) Active Optics Pipeline. We present a comprehensive analysis of the wave-front sensing system, including the availability of reference stars, pupil registration, wavefront estimators and the iteration matrix evaluation techniques. Some preliminary simulations have been made using a telescope model with a Optical Ray Tracing Software.

Chueca, Sergio; Marín-Franch, Antonio; Cenarro, Andrés. Javier; Varela, Jesús; Ederoclite, Alessandro; Cristóbal-Hornillos, David; Hernández-Monteagudo, Carlos; Gruel, Nicolás.; Moles, Mariano; Yanes, Axel; Rueda, Fernando; Rueda, Sergio; Luis-Simoes, Roberto; Hernández-Fuertes, Javier; López-Sainz, Angel; Maícas-Sacristán, Natalio; Lamadrid, José Luis; Díaz-Martín, Miguel Chioare; Taylor, Keith

2012-09-01

135

Restoration of observed image with an unknown space-variant blur from wide-field telescope  

NASA Astrophysics Data System (ADS)

The field-of-view (FOV) of wide-field telescope is mostly beyond the scope of isoplanatic angle. Though the aberrated wave-front within a limited range close to guide star could be corrected accurately by adaptive-optics (AO) system, the image quality of object region deviation from guide star is dropped severely. The post-processing technique to restore degraded image observed from wide-field telescope is a good compensation for the limit of AO system. Restoration method of space-variant point spread function (PSF) degraded image which are used to overcome the turbulence-induced anisoplanatic effect, can improve image quality in the whole field of view of wide-field telescope, and restore image resolution to optical diffraction-limited level in free space. A multi-frame blind deconvolution restoration algorithm based on image sectioning method is presented here. The image is divided into several subimages, where the PSF of each subimage is assumed to be space-invariant. The conjugate gradient optimization algorithm based on maximum likelihood estimation (MLE) in space domain is adopted to estimate the space-invariant PSF and object information in each block. In order to reduce blocking artifacts at the subregion boundaries, larger, overlapping subregions as well as the Mumford- Shah regularization are used, and then the restored sections are extracted from their center. The resolution of the restored image using 5 satellite model blurred image frames through image sectioning method is enhanced significantly, compared to the space-invariant PSF restoration approach. There are more details about the original object, and it shows the proposed algorithm is valid.

He, Chaolan; Wei, Honggang; Shen, Mangzuo

2012-09-01

136

Diffuse optical tomography: Present status and its future  

NASA Astrophysics Data System (ADS)

Diffuse optical tomography (DOT) is one of the emerging modalities for the non-invasive imaging of thick biological tissues using near-infrared (NIR) light. This article reviews the fundamentals and development of DOT technology since its advent in the early 1990s, including the modeling of light propagation in biological tissues which strongly scatter and weakly absorb NIR light, the optical properties of biological tissues in the NIR wavelength range, three typical measurement methods, image reconstruction algorithms, and so forth. Then various studies are referred to for improvement of the DOT images, which are essentially low in quality due to the ill-conditioned and underdetermined problem. Studies and clinical applications presently attracting much attention are discussed in some detail. Finally, the expected future developments are summarized.

Yamada, Yukio; Okawa, Shinpei

2014-05-01

137

Indoor optical wireless communications: recent developments and future challenges  

NASA Astrophysics Data System (ADS)

Wireless communications is facing the challenges of a predicted 'explosion' in the number of wireless devices, demand for higher capacity, and the need to reduce power consumption in order to lower greenhouse gas emissions. Optical Wireless (OW) communications may have a part to play in helping to achieve these aims. High speed line of sight optical wireless systems have the potential to provide a low complexity alternative to high frequency RF wireless communications, and may offer lower energy consumption. Visible light communications is also a growing area of interest. Low energy solid-state lighting sources can be modulated to provide data communications, and this can augment the communications provided by other wireless techniques. In this paper we review progress in these areas. Examples and results from systems will be reported, together with future directions and challenges..

O'Brien, Dominic

2009-08-01

138

Wide-field imaging of the polarized sky with PAPER  

NASA Astrophysics Data System (ADS)

We present maps of the polarised southern sky as seen by the Donald C. Backer Precision Array for Probing the Epoch of Reionization (PAPER). Polarized emission is a potential systematic contaminant of the redshifted 21cm signature of neutral hydrogen during reionization, the detection of which is PAPER's primary goal. We use commissioning data from 32 dual-polarization antennas in a minimum-redundancy configuration to create wide-field images in Stokes I, Q, U and V. Here we compare the results of imaging using W-projection and faceting versus m-mode mapping (Shaw et al. 2014a,b), a technique specifically adapted to transit arrays which allows an exact treatment of the spherical sky. We explore differences in the images and potential methods for using the m-mode formalism to extract polarization calibration parameters.

Aryeh Kohn, Saul; Aguirre, James E.; Moore, David; Ling, Jason; Bernardi, Gianni; Paper

2015-01-01

139

Wide Field X-Ray Telescope Mission Concept Study Results  

NASA Technical Reports Server (NTRS)

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.

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

140

Dynamic speckle illumination wide-field reflection phase microscopy.  

PubMed

We demonstrate a quantitative reflection-phase microscope based on time-varying speckle-field illumination. Due to the short spatial coherence length of the speckle field, the proposed imaging system features superior lateral resolution, 520 nm, as well as high-depth selectivity, 1.03 ?m. Off-axis interferometric detection enables wide-field and single-shot imaging appropriate for high-speed measurements. In addition, the measured phase sensitivity of this method, which is the smallest measurable axial motion, is more than 40 times higher than that available using a transmission system. We demonstrate the utility of our method by successfully distinguishing the motion of the top surface from that of the bottom in red blood cells. The proposed method will be useful for studying membrane dynamics in complex eukaryotic cells. PMID:25361156

Choi, Youngwoon; Hosseini, Poorya; Choi, Wonshik; Dasari, Ramachandra R; So, Peter T C; Yaqoob, Zahid

2014-10-15

141

Wide field imaging for the square kilometre array  

NASA Astrophysics Data System (ADS)

Wide-field radio interferometric telescopes such as the Square Kilometre Array now being designed are subject to a number of aberrations. One particularly pernicious aberration is that due to non-coplanar baselines whereby long baselines incur a quadratic image-plane phase error. There are numerous algorithms for dealing with the non-coplanar baselines effect. As a result of our experience with developing processing software for the Australian Square Kilometre Array Pathinder, we advocate the use of a hybrid algorithm, called w snapshots, based on a combination of w projection and snapshot imaging. This hybrid overcomes some of the deficiencies of each and has advantages from both. Compared to pure w projection, w snapshots uses less memory and execution time, and compared to pure snapshot imaging, w snapshots uses less memory and is more accurate. At the asymptotes, w snapshots devolves to w projection and to snapshots.

Cornwell, T. J.; Voronkov, M. A.; Humphreys, B.

2012-10-01

142

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

NASA Technical Reports Server (NTRS)

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.

Prechtl, Eric F.; Sedwick, Raymond J.

2010-01-01

143

Temporally focused wide-field two-photon microscopy: Paraxial to vectorial  

PubMed Central

Temporal focusing allows for optically sectioned wide-field microscopy. The optical sectioning arises because this method takes a pulsed input beam, stretches the pulses by diffracting off a grating, and focuses the stretched pulses such that only at the focal plane are the pulses re-compressed. This approach generates nonlinear optical processes at the focal plane and results in depth discrimination. Prior theoretical models of temporal focusing processes approximate the contributions of the different spectral components by their mean. This is valid for longer pulses that have narrower spectral bandwidth but results in a systematic deviation when broad spectrum, femtosecond pulses are used. Further, prior model takes the paraxial approximation but since these pulses are focused with high numerical aperture (NA) objectives, the effects of the vectorial nature of light should be considered. In this paper we present a paraxial and a vector theory of temporal focusing that takes into account the finite spread of the spectrum. Using paraxial theory we arrive at an analytical solution to the electric field at the focus for temporally focused wide-field two-photon (TF2p) microscopy as well as in the case of a spectrally chirped input beam. We find that using paraxial theory while accounting for the broad spectral spread gives results almost twice vector theory. Experiment results agree with predictions of the vector theory giving an axial full-width half maximum (FWHM) of 2.1 ?mand 1.8 ?mrespectively as long as spectral spread is taken into account. Using our system parameters, the optical sectioning of the TF2p microscope is found to be 8 ?m. The optical transfer function (OTF) of a TF2p microscope is also derived and is found to pass a significantly more limited band of axial frequencies than a point scanning two-photon (2p) microscope or a single photon (1p) confocal microscope. PMID:23736515

Yew, Elijah Y. S.; Sheppard, Colin J. R.; So, Peter T. C.

2013-01-01

144

Designing contact lenses for a wide field of view via ocular wavefront tomography  

PubMed Central

Purpose Correcting the off-axis wavefront aberration is potentially important for peripheral vision, for diagnostic imaging of the retina, and for influencing refractive development. A new technique called ocular wavefront tomography (OWT) was adapted to optimize the design of contact lenses to improve the eye's peripheral optical quality. Methods OWT is a technique for customizing a multi-surface model eye to mimic the off-axis wavefront aberrations for an individual eye. This technique was adapted for contact lens design by establishing clear design goals for the eye + contact lens system. To demonstrate the method we optimized the shape of an aspheric and bifocal contact lens to correct a wide angle model eye with ?2D foveal myopia. Two strategies for correction reflected alternative design goals: 1) to fully correct central vision while also improving optical quality peripherally to enhance vision and retinal imaging, or 2) fully correct central vision while introducing a degree of peripheral myopia relative to central vision in order to slow myopia progression. Results The OWT technique successfully produced aspheric and bifocal contact lens designs over a wide field of view. In addition to correcting foveal vision, the optimized contact lens designs either 1) improved the retinal image quality across the visual field (< 45°) significantly to obtain a visual performance and retinal imaging benefit or 2) produced the desired level of myopia in the peripheral field to obtain a refractive development benefit. Conclusion The OWT technique is a validated tool to optimize contact lens design over a wide field.

Wei, Xin; Thibos, Larry

2010-01-01

145

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

NASA Technical Reports Server (NTRS)

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.

Fazio, Giovanni G.

1988-01-01

146

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

NASA Astrophysics Data System (ADS)

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 light curves of bright main-belt asteroids, space-debris detection, and stationary transient events like novae, supernovae, variable stars, and microlensing. The budget for the prototype development and testing is estimated to be 1,000,000 EUR. The planned development time is one year.

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

2014-07-01

147

Modeling the effect of high altitude turbulence in wide-field correlating wavefront sensing and its impact on the performance of solar AO systems  

NASA Astrophysics Data System (ADS)

Solar Adaptive Optics (AO) shares many issues with night-time AO, but it also has its own particularities. The wavefront sensing is performed using correlations to efficiently work on the solar granulation as a reference. The field of view for that measurement usually is around 10". A sensor collecting such a wide field of view averages wavefront information from different sky directions, and the anisoplanatism thus has a peculiar impact on the performance of solar AO and MCAO systems. Since we are entering the era of large solar telescopes (European Solar Telescope, Advanced Technology Solar Telescope) understanding this issue is crucial to evaluate its impact on the performance of future AO systems. In this paper we model the correlating wide field sensor and the way it senses the high altitude turbulence. Thanks to this improved modelling, we present an analysis of the influence of this sensing on the performance of each AO configuration, conventional AO and MCAO. In addition to the analytical study, simulations similar to the case of the EST AO systems with FRiM-3D (the Fractal Iterative Method for Atmospheric tomography) are used in order to highlight the relative influence of design parameters. In particular, results show the performance evolution when increasing the telescope diameter. We analyse the effect of high altitude turbulence correlation showing that increasing the diameter of the telescope does not degrade the performance when correcting on the same spatial and temporal scales.

Montilla, I.; Tallon, M.; Langlois, M.; Béchet, C.; Collados Vera, M.

2014-08-01

148

The first light of Mini-MegaTORTORA wide-field monitoring system  

E-print Network

Here we describe the first light of the novel 9-channel wide-field optical monitoring system with sub-second temporal resolution, Mini-MegaTORTORA, which is being tested 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 B, V or R) polarimetric filters installed, with exposure times ranging from 100 ms to 100 s. The primary goal of the system is the detection of rapid -- with sub-second characteristic time-scales -- optical transients, but it may be also used for studying the variability of the sky objects on longer time scales.

Biryukov, A; Karpov, S; Bondar, S; Ivanov, E; Katkova, E; Perkov, A; Sasyuk, V

2014-01-01

149

Wide-Field Infrared Survey Telescope (WFIRST) Interim Report  

NASA Technical Reports Server (NTRS)

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 1Wide-field Infrared Sur-vey Explorer (WISE) are all space missions that have produced stunning new scientific advances by going to space to observe in the infrared. This interim report describes progress as of June 2011 on developing a requirements flowdown and an evaluation of scientific performance. An Interim Design Reference Mission (IDRM) configuration is presented that is based on the specifications of NWNH with some refinements to optimize the design in accordance with the new scientific requirements. Analysis of this WFIRST IDRM concept is in progress to ensure the capability of the observatory is compatible with the science requirements. The SDT and Project will continue to refine the mission concept over the coming year as design, analysis and simulation work are completed, resulting in the SDT s WFIRST Design Reference Mission (DRM) by the end of 2012.

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

150

Status and Performance of HST/Wide Field Camera 3  

NASA Technical Reports Server (NTRS)

The HST Wide Field Camera 3 is a panchromatic UV-visible-near infrared camera whose development is currently nearing completion, for a planned installation into the Hubble Space Telescope during Servicing Mission 4. WFC3 provides two imaging channels. The UVIS channel features a 4096 x 4096 pixel CCD focal plane with sensitivity from 200 to 1000 nm and a 160 x 160 arcsec field of view. The UVIS channel provides unprecedented sensitivity and field of view in the near ultraviolet for HST. The IR channel features a 1014 x 1014 pixel HgCdTe focal plane covering 850 to 1700 nm with a 135 x 135 arcsec field of view, providing an order of magnitude increase in J+H band surveying efficiency for HST. WFC3 offers a rich complement of filters and grisms in each channel. The construction of WFC3 is nearly complete, and the instrument is well into its integration and test program. We present the current status of the instrument and its projected scientific performance.

Kimble, Randy

2004-01-01

151

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

PubMed

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

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

2015-01-01

152

Instrumental and scientific simulations of the LOFT wide field monitor  

NASA Astrophysics Data System (ADS)

The Large Observatory for X-ray Timing (LOFT) is one of the five candidates that were considered by ESA as an M3 mission (with launch in 2022-2024). It is specifically designed to exploit the diagnostics of very rapid X-ray flux and spectral variability that directly probe the motion of matter down to distances very close to black holes and neutron stars, as well as the physical state of ultradense matter. The LOFT scientific payload is composed of the Large Area Detector (LAD), devoted to spectral-timing observation, and the Wide Field Monitor (WFM), whose primary goal it is to monitor the X-ray sky for transient events that need to be followed up with the LAD, and to measure the long-term variability of galactic X-ray sources and localize gamma-ray bursts. Here we describe the simulations carried out to optimize the WFM design and to characterize the instrument response to both isolated sources and crowded fields in the proximity of the galactic bulge.

Evangelista, Y.; Donnarumma, I.; Campana, R.; Schmid, C.; Feroci, M.

2014-07-01

153

Wide Field-of-View Fluorescence Imaging of Coral Reefs  

PubMed Central

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

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

2015-01-01

154

Wide Field-of-View Fluorescence Imaging of Coral Reefs  

NASA Astrophysics Data System (ADS)

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.

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

2015-01-01

155

Three-dimensional resolution doubling in wide-field fluorescence microscopy by structured illumination.  

PubMed

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

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

2008-06-01

156

The 64 Mpixel wide field imager for the Wendelstein 2m telescope: design and calibration  

NASA Astrophysics Data System (ADS)

The Wendelstein Observatory of Ludwig Maximilians University of Munich has recently been upgraded with a modern 2m robotic telescope. One Nasmyth port of the telescope has been equipped with a wide-field corrector which preserves the excellent image quality (<0.8 " median seeing) of the site (Hopp et al. 2008) over a field of view of 0.7 degrees diameter. The available field is imaged by an optical imager (WWFI, the Wendelstein Wide Field Imager) built around a customized 2×2 mosaic of 4 k×4 k 15 ?m e2v CCDs from Spectral Instruments. This paper provides an overview of the design and the WWFI's performance. We summarize the system mechanics (including a structural analysis), the electronics (and its electromagnetic interference (EMI) protection) and the control software. We discuss in detail detector system parameters, i.e. gain and readout noise, quantum efficiency as well as charge transfer efficiency (CTE) and persistent charges. First on sky tests yield overall good predictability of system throughput based on lab measurements.

Kosyra, Ralf; Gössl, Claus; Hopp, Ulrich; Lang-Bardl, Florian; Riffeser, Arno; Bender, Ralf; Seitz, Stella

2014-11-01

157

The 64 Mpixel wide field imager for the Wendelstein 2m telescope: design and calibration  

NASA Astrophysics Data System (ADS)

The Wendelstein Observatory of Ludwig Maximilians University of Munich has recently been upgraded with a modern 2m robotic telescope. One Nasmyth port of the telescope has been equipped with a wide-field corrector which preserves the excellent image quality (<0.8" median seeing) of the site (Hopp et al. 2008) over a field of view of 0.7 degrees diameter. The available field is imaged by an optical imager (WWFI, the Wendelstein Wide Field Imager) built around a customized 2×2 mosaic of 4k×4k 15 ?m e2v CCDs from Spectral Instruments. This paper provides an overview of the design and the WWFI's performance. We summarize the system mechanics (including a structural analysis), the electronics (and its electromagnetic interference (EMI) protection) and the control software. We discuss in detail detector system parameters, i.e. gain and readout noise, quantum efficiency as well as charge transfer efficiency (CTE) and persistent charges. First on sky tests yield overall good predictability of system throughput based on lab measurements.

Kosyra, Ralf; Gössl, Claus; Hopp, Ulrich; Lang-Bardl, Florian; Riffeser, Arno; Bender, Ralf; Seitz, Stella

2014-08-01

158

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

PubMed Central

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 cm2) 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 ~10 µm spatial resolution over the entire active region of the sensor-array, i.e., over an imaging field-of-view of >8 cm2. 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. PMID:20588904

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

2010-01-01

159

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

NASA Astrophysics Data System (ADS)

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.

Moore, Anna M.; McGrath, Andrew J.

2004-07-01

160

Objective evaluation of 3-D wide-field effect by human postural control analysis  

NASA Astrophysics Data System (ADS)

A new evaluation method of visual wide-field effects using human postural control analysis is proposed. In designing a television system for future, it is very important to understand the dynamic response of human beings in order to evaluate the visual effects of displayed images objectively. Visual effects produced by 3-D wide-field images are studied. An observer's body sway produced by postural control is discussed using rotating 2-D and 3-D images. Comparisons between stationary and rotating images are also performed. A local peak appears in power spectra of the body sway for the rotating images (3-D and 2-D). On the other hand, no distinctive component appears in the power spectra for the stationary images. By extending the visual field, the cyclic component can be proved from the audio-correlation function of the body sway for the rotating images. These results suggest that displayed images induce the postural control. The total length of the body sway locus is also analyzed to evaluate the postural control. The total length for the rotating images increases in proportion to viewing angles, and is nearly saturated after 50 (deg). Moreover, it is shown that the total length for the rotating 3-D image is greater than for the rotating 2-D image.

Shimizu, Toshihiro; Yano, Sumio; Mitsuhashi, Tetsuo

1992-08-01

161

Wide-field Functional Imaging of Blood Flow and Hemoglobin Oxygen Saturation in the Rodent Dorsal Window Chamber  

PubMed Central

The rodent dorsal window chamber is a widely used in vivo model of the microvasculature. The model consists of a 1cm region of exposed microvasculature in the rodent dorsal skin that is immobilized by surgically implanted titanium frames, allowing the skin microvasculature to be visualized. We describe a detailed protocol for surgical implantation of the dorsal window chamber which enables researchers to perform the window chamber implantation surgery. We further describe subsequent wide-field functional imaging of the chamber to obtain hemodynamic information in the form of blood oxygenation and blood flow on a cm size region of interest. Optical imaging techniques, such as intravital microscopy, have been applied extensively to the dorsal window chamber to study microvascular-related disease and conditions. Due to the limited field of view of intravital microscopy, detailed hemodynamic information typically is acquired from small regions of interest, typically on the order of hundreds of ?m. The wide-field imaging techniques described herein complement intravital microscopy, allowing researchers to obtain hemodynamic information at both microscopic and macroscopic spatial scales. Compared with intravital microscopy, wide-field functional imaging requires simple instrumentation, is inexpensive, and can give detailed metabolic information over a wide field of view. PMID:21787792

Moy, Austin J.; White, Sean M.; Indrawan, Elmer S.; Lotfi, Justin; Nudelman, Matthew J.; Costantini, Samantha J.; Agarwal, Nikita; Jia, Wangcun; Kelly, Kristen M.; Sorg, Brian S.; Choi, Bernard

2011-01-01

162

Three wide-field telescopes with spherical primary mirrors  

NASA Astrophysics Data System (ADS)

This paper presents three optical designs based on the work of Maurice Paul. Paul's three-mirror anastigmats produce well-corrected, distortion-free fields of view. His design equations can be solved for a spherical primary mirror with one limitation: the image field is curved. Adding all-spherical refractive field-flattening optics yields well-corrected, flat image-fields of two degrees angular diameter or more. These designs can be scaled to very large telescopes with current technology.

Blanco, Dan

2014-07-01

163

Characterization of spatially varying aberrations for wide field-of-view microscopy  

PubMed Central

We describe a simple and robust approach for characterizing the spatially varying pupil aberrations of microscopy systems. In our demonstration with a standard microscope, we derive the location-dependent pupil transfer functions by first capturing multiple intensity images at different defocus settings. Next, a generalized pattern search algorithm is applied to recover the complex pupil functions at ~350 different spatial locations over the entire field-of-view. Parameter fitting transforms these pupil functions into accurate 2D aberration maps. We further demonstrate how these aberration maps can be applied in a phase-retrieval based microscopy setup to compensate for spatially varying aberrations and to achieve diffraction-limited performance over the entire field-of-view. We believe that this easy-to-use spatially-varying pupil characterization method may facilitate new optical imaging strategies for a variety of wide field-of-view imaging platforms. PMID:23842300

Zheng, Guoan; Ou, Xiaoze; Horstmeyer, Roarke; Yang, Changhuei

2013-01-01

164

Fabrication of bioinspired omnidirectional and gapless microlens array for wide field-of-view detections  

NASA Astrophysics Data System (ADS)

Microlens arrays on curvilinear surfaces are highly desirable for wide field-of-view imaging and sensing systems. However, it is technically challenging to fabricate these structures. This letter reports a simple method to machine close-packed microlenses on curvilinear surfaces as inspired by the insect eyes, which involves a femtosecond-laser-based microfabrication and a thermomechanical bending process. Over 7600 hexagonal-shaped microlenses with a diameter of 50 ?m were fabricated on a hemispherical poly (methyl methacrylate) shell, which is similar to the compound eyes of insects. The optical performances of the microlens array were demonstrated by the abilities of high-resolution imaging and large view-angle focusing.

Liu, Hewei; Chen, Feng; Yang, Qing; Qu, Pubo; He, Shengguan; Wang, Xianhua; Si, Jinhai; Hou, Xun

2012-03-01

165

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

NASA Astrophysics Data System (ADS)

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.

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

2011-03-01

166

Signal-to-noise ratio for the wide field-planetary camera of the Space Telescope  

NASA Technical Reports Server (NTRS)

Signal-to-noise ratios for the Wide Field Camera and Planetary Camera of the Space Telescope were calculated as a function of integration time. Models of the optical systems and CCD detector arrays were used with a 27th visual magnitude point source and a 25th visual magnitude per arc-sq. second extended source. A 23rd visual magnitude per arc-sq. second background was assumed. The models predicted signal-to-noise ratios of 10 within 4 hours for the point source centered on a signal pixel. Signal-to-noise ratios approaching 10 are estimated for approximately 0.25 x 0.25 arc-second areas within the extended source after 10 hours integration.

Zissa, D. E.

1984-01-01

167

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

NASA Technical Reports Server (NTRS)

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).

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

168

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

NASA Technical Reports Server (NTRS)

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.

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

169

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

NASA Technical Reports Server (NTRS)

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.

Peabody, Hume; Stavley, Richard; Bast, William

2007-01-01

170

GRAAL: a seeing enhancer for the NIR wide-field imager Hawk-I  

NASA Astrophysics Data System (ADS)

We describe the design and development status of GRAAL, the Ground-layer adaptive optics assisted by Laser, which will deliver enhanced images to the Hawk-I instrument on the VLT. GRAAL is an adaptive optics module, part of AOF, the Adaptive optics facility, 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. The outstanding feature of GRAAL is the extremely wide field of view correction, over 10 arcmin diameter, with an image enhancement of about 20% in average in K band. When observing GRAAL will provide FWHM better than 0.3" 40% of the time. Besides the Adaptive optics facility deformable mirror and Laser guide stars, the system uses subelectron L3-CCD and a real-time computing platform, SPARTA. GRAAL completed early this year a final design phase shared internally and outsourced for its mechanical part by the Spanish company NTE. It is now in manufacturing, with a first light in the laboratory planned in 2011.

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

2010-07-01

171

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

NASA Astrophysics Data System (ADS)

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 ?m 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.

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

172

Wide-field tracking with zenth-pointing telescopes  

E-print Network

Equipped with a suitable optical relay system, telescopes employing low-cost fixed primary mirrors could point and track while delivering high-quality images to a fixed location. Such an optical tracking system would enable liquid-mirror telescopes to access a large area of sky and employ infrared detectors and adaptive optics. Such telescopes could also form the elements of an array in which light is combined either incoherently or interferometrically. Tracking of an extended field requires correction of all aberrations including distortion, field curvature and tilt. A specific design is developed that allows a 10-metre liquid-mirror telescope to track objects for as long as 30 minutes and to point as far as 4 degrees from the zenith, delivering a distortion-free diffraction-limited image to a stationary detector, spectrograph, or interferometric beam combiner.

Paul Hickson

2001-06-12

173

Integral wide-field spectroscopy in astronomy: the Imaging FTS solution  

NASA Astrophysics Data System (ADS)

Long-slit grating spectrometers in scanning mode and Fabry-Perot interferometers as tunable filters are commonly used to perform integral wide-field spectroscopy on extended astrophysical objects as HII regions and nearby galaxies. The goal of this paper is to demonstrate, by comparison, through a thorough review of the imaging Fourier transform spectrometer (IFTS) properties, that this instrument represents another interesting solution. After a brief recall of the performances, regarding FOV and spectral resolution, of the grating spectrometer, without and with integral field units (IFU), and of the imaging Fabry-Perot, it is demonstrated that for an IFTS the product of the maximum resolution R by the entrance beam étendue U is equal to 2.6 N× S_I with N × N the number of pixels of the detector array and S_I the area of the interferometer beamsplitter. As a consequence, the IFTS offers the most flexible choice of field size and spectral resolution, up to high values for both parameters. It also presents on a wide field an important multichannel advantage in comparison to integral field grating spectrometers, even with multiple IFUs. To complete, the few astronomical IFTSs, built behind ground-based telescopes and in space, for the visible range up to the sub-millimetric domain, are presented. Through two wide-field IFTS projects, one in the visible, the other one in the mid-infrared, the question is addressed of the practical FOV and resolution limits, set by the optical design of the instrument, which can be achieved. Within the 0.3 to ˜ 2.5 \\upmum domain, a Michelson interferometer with wide-field diopric collimators provides the easiest solution. This design is illustrated by a 11^'× 11^'-field IFTS in the 0.35-0.90 \\upmum range around an off-axis interferometer, called SITELLE, proposed for the 3.6-m CFH Telescope. At longer wavelengths, an all-mirror optics is required, as studied for a spaceborne IFTS, H2EX, for the 8-29 \\upmum range, a 20^' × 20^' field, and a high resolution of ˜eq 3× 10^4 at 10 \\upmum. To comply with these characteristics, the interferometer is designed with cat's eye retroreflectors. In the same domain and up to the far infrared, if the instrument aims only at a low spectral resolution (few thousands) and a smaller field (few arcmins^2), roof-top or corner cube mirrors, as for the IFTS SPIRE on the Herschel space telescope, are usable. At last, perspectives are opened, behind an ELT in the visible and the near infrared with the SITELLE optical combination, in the 2-5 \\upmum on the Antarctic plateau or in space up to longer wavelengths, with the H2EX design, to provide the missing capability of global high spectral resolution studies of extended sources, from comets to distant galaxy clusters.

Maillard, J. P.; Drissen, L.; Grandmont, F.; Thibault, S.

2013-04-01

174

Wide field x-ray telescope a moderate class mission  

E-print Network

Sensitive surveys of the X-ray universe have been limited to small areas of the sky due to the intrinsically small field of view of Wolter-I X-ray optics, whose angular resolution degrades with the square of the off axis ...

Murray, Stephen S.

175

Alignment of four-mirror wide field corrector for the Hobby-Eberly Telescope  

NASA Astrophysics Data System (ADS)

The Hobby-Eberly Telescope (HET) Wide Field Corrector (WFC) is a four-mirror optical system which corrects for aberrations from the 10-m segmented spherical primary mirror. The WFC mirror alignments must meet particularly tight tolerances for the system to meet performance requirements. The system uses 1-m class highly aspheric mirrors, which precludes conventional alignment methods. For the WFC system alignment a "center reference fixture" has been used as the reference for each mirror's vertex and optical axis. The center reference fixtures have both a CGH and sphere mounted retroreflector (SMR) nests. The CGH is aligned to the mirror's optical axis to provide a reference for mirror decenter and tilt. The vertex of each mirror is registered to the SMR nests on the center reference fixtures using a laser tracker. The spacing between the mirror vertices is measured during the system alignment using these SMR nest locations to determine the vertex locations. In this paper we present the procedures and results from creating and characterizing these center reference fixtures. As a verification of our alignment methods we also present results from their application in the WFC system alignment are also presented.

Oh, Chang Jin; Frater, Eric H.; Coyle, Laura; Dubin, Matt; Lowman, Andrew; Zhao, Chunyu; Burge, James H.

2013-09-01

176

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

PubMed Central

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. PMID:22574249

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

177

A freeform-based, fast, wide-field, and distortion-free camera for ultralow surface brightness surveys  

NASA Astrophysics Data System (ADS)

Testing the predictions of galaxy formation scenarios on mildly- and non-linear regimes requires the detection from space of ultra-low surface brightness features both around galaxies (dwarf satellites) and in the cosmic web (filaments). The requirements of such a space mission imply innovative concepts for fast, wide-field, distortion-free telescopes. Several optical designs, based on freeform mirrors, are presented and compared here to address these stringent constraints on space-borne, wide field drift-scanning imaging. An optimal solution is presented, showing that a telescope with f/2, 4° × 2° FoV, with a 50 cm pupil can achieve the required exquisite image quality, free of distortion, with an optimal SNR in the detection of ultra-low surface brightness.

Hugot, Emmanuel; Wang, Xin; Valls-Gabaud, David; Lemaître, Gérard; Agócs, Tibor; Shu, Rong; Wang, Jianyu

2014-08-01

178

Development of a wide field spherical aberration corrector for the Hobby Eberly Telescope: design, fabrication and alignment  

NASA Astrophysics Data System (ADS)

A 4-mirror prime focus corrector is under development to provide seeing-limited images for the 10-m aperture Hobby- Eberly Telescope (HET) over a 22 arcminute wide field of view. The images created by the spherical primary mirror are aberrated with 13 arcmin diameter point spread function. The University of Arizona is developing the 4-mirror wide field corrector to compensate the aberrations from the primary mirror and present seeing limited imaged to the pickoffs for the fiber-fed spectrographs. The requirements for this system pose several challenges, including optical fabrication of the aspheric mirrors, system alignment, and operational mechanical stability. This paper presents current status of the program which covers fabrication of mirrors and structures and pretest result from the alignment of the system.

Oh, Chang Jin; Frater, Eric; Lowman, Andrew E.; Su, Peng; Zhao, Chunyu; Zhou, Ping; Burge, James H.

2014-07-01

179

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

NASA Technical Reports Server (NTRS)

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.

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

180

High-Resolution, Wide-Field-of-View Scanning Telescope  

NASA Technical Reports Server (NTRS)

A proposed telescope would afford high resolution over a narrow field of view (<0.10 ) while scanning over a total field of view nominally 16 wide without need to slew the entire massive telescope structure. The telescope design enables resolution of a 1-m-wide object in a 50- km-wide area of the surface of the Earth as part of a 200-km-wide area field of view monitored from an orbit at an altitude of 700 km. The conceptual design of this telescope could also be adapted to other applications both terrestrial and extraterrestrial in which there are requirements for telescopes that afford both wide- and narrow-field capabilities. In the proposed telescope, the scanning would be effected according to a principle similar to that of the Arecibo radio telescope, in which the primary mirror is stationary with respect to the ground and a receiver is moved across the focal surface of the primary mirror. The proposed telescope would comprise (1) a large spherical primary mirror that would afford high resolution over a narrow field of view and (2) a small displaceable optical relay segment that would be pivoted about the center of an aperture stop to effect the required scanning (see figure). Taken together, both comprise a scanning narrow-angle telescope that does not require slewing the telescope structure. In normal operation, the massive telescope structure would stare at a fixed location on the ground. The inner moveable relay optic would be pivoted to scan the narrower field of view over the wider one, making it possible to retain a fixed telescope orientation, while obtaining high-resolution images over multiple target areas during an interval of 3 to 4 minutes in the intended orbit. The pivoting relay segment of the narrow-angle telescope would include refractive and reflective optical elements, including two aspherical mirrors, to counteract the spherical aberration of the primary mirror. Overall, the combination of the primary mirror and the smaller relay optic would provide narrow-angle, diffraction-limited high resolution at a wavelength of 500 nm.

Sepulveda, Cesar; Wilson, Robert; Seshadri, Suresh

2007-01-01

181

Optical Tecnology Developments in Biomedicine: History, Current and Future  

PubMed Central

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

Nioka, Shoko; Chen, Yu

2011-01-01

182

Adaptive optics schemes for future extremely large telescopes  

Microsoft Academic Search

The adaptive optics for any telescope in the 25- to 100-m class will be complex. It is believed that adaptive optics should, to the maximum extent, be designed as an integrated part of a telescope. The proposed Swedish 50-m Extremely Large Telescope is considered here to illustrate the principle of integrated adaptive optics. Two alternative designs both using the Ritchey-Chretien

Alexander V. Goncharov; Mette Owner-Petersen; Torben Andersen; Jacques M. Beckers

2002-01-01

183

Wide-Field High-Performance Geosynchronous Imaging  

NASA Technical Reports Server (NTRS)

The NASA Mission to Planet Earth (MTPE) Program and the National Oceanographic and Atmospheric Administration (NOAA) are sponsoring the Advanced Geosynchronous Studies (AGS) to develop technologies and system concepts for Earth observation from geosynchronous orbit. This series of studies is intended to benefit both MTPE science and the NOAA GOES Program. Within the AGS program, advanced imager trade studies have investigated two candidate concepts for near-term advanced geosynchronous imagers. One concept uses a scan mirror to direct the line of sight from a 3-axis stabilized platform. Another eliminates the need for a scan mirror by using an agile spacecraft bus to scan the entire instrument. The purpose of this paper is to discuss the optical design trades and system issues encountered in evaluating the two scanning approaches.

Wood, H. John; Jenstrom, Del; Wilson, Mark; Hinkal, Sanford; Kirchman, Frank

1997-01-01

184

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

PubMed

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

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

2014-01-01

185

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

NASA Astrophysics Data System (ADS)

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.

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

2014-12-01

186

Phase-retrieved pupil functions in wide-field fluorescence microscopy.  

PubMed

Pupil functions are compact and modifiable descriptions of the three-dimensional (3D) imaging properties of wide-field optical systems. The pupil function of a microscope can be computationally estimated from the measured point spread function (PSF) using phase retrieval algorithms. The compaction of a 3D PSF into a 2D pupil function suppresses artefacts and measurement noise without resorting to rotational averaging. We show here that such 'phase-retrieved' pupil functions can reproduce features in the optical path, both near the sample and in the microscope. Unlike the PSF, the pupil function can be easily modified to include known aberrations, such as those induced by index-mismatched mounting media, simply by multiplying the pupil function by a calculated aberration function. PSFs calculated from such a modified pupil function closely match the corresponding measured PSFs collected under the aberrated imaging conditions. When used for image deconvolution of simulated objects, these phase-retrieved, calculated PSFs perform similarly to directly measured PSFs. PMID:15369481

Hanser, B M; Gustafsson, M G L; Agard, D A; Sedat, J W

2004-10-01

187

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

PubMed Central

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

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

2014-01-01

188

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

PubMed

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. PMID:23742532

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

2013-05-01

189

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

NASA Astrophysics Data System (ADS)

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.

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

2013-05-01

190

From classical to modern near-field optics and the future  

NASA Astrophysics Data System (ADS)

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.

Ohtsu, Motoichi

2014-11-01

191

Role of wide-field autofluorescence imaging and scanning laser ophthalmoscopy in differentiation of choroidal pigmented lesions  

PubMed Central

AIM To evaluate the diagnostic properties of wide-field fundus autofluorescence (FAF) scanning laser ophthalmoscope (SLO) imaging for differentiating choroidal pigmented lesions. METHODS A consecutive series of 139 patients were included, 101 had established choroidal melanoma with 13 untreated lesions and 98 treated with radiotherapy. Thirty-eight had choroidal nevi. All patients underwent a full ophthalmological examination, undilated wide-field imaging, FAF and standardized US examination. FAF images and imaging characteristics from SLO were correlated with the structural findings in the two patient groups. RESULTS Mean FAF intensity of melanomas was significantly lower than the FAF of choroidal nevi. Only 1 out of 38 included eyes with nevi touched the optic disc compared to 31 out of 101 eyes with melanomas. In 18 out of 101 melanomas subretinal fluid was seen at the pigmented lesion compared to none seen in eyes with confirmed choroidal nevi. In “green laser separation”, a trend towards more mixed FAF appearance of melanomas compared to nevi was observed. The mean maximal and minimal transverse and longitudinal diameters of melanomas were significantly higher than those of nevi. CONCLUSION Wide-field SLO and FAF imaging may be an appropriate non-invasive diagnostic screening tool to differentiate benign from malign pigmented choroidal lesions. PMID:25161946

Reznicek, Lukas; Stumpf, Carmen; Seidensticker, Florian; Kampik, Anselm; Neubauer, Aljoscha S; Kernt, Marcus

2014-01-01

192

Design of a wide field of view infrared scene projector  

NASA Astrophysics Data System (ADS)

In order to make the projected scene cover the seeker's field-of-view promptly the conventional projection optical systems used for hardware-in-the-loop simulation test usually depend on the 5 axes flight-motion-simulator. Those flight-motion-simulator tables are controlled via servomechanisms. The servomechanism needs many axis position transducers and many electromechanical devices. The structure and controlling procedure of the system are complicated. It is hard to avoid the mechanical motion and controlling errors absolutely. The target image jitter will be induced by the vibration of mechanical platform, and the frequency response is limited by the structural performance. To overcome these defects a new infrared image simulating projection system for hardware-in-the-loop simulation test is presented in this paper. The system in this paper consists of multiple lenses joined side by side on a sphere surface. Each single lens uses one IR image generator or resistor array etc. Every IR image generator displays special IR image controlled by the scene simulation computer. The scene computer distributes to every IR image generator the needed image. So the scene detected by the missile seeker is integrated and uninterrupted. The entrance pupil of the seeker lies in the centre of the sphere. Almost semi-sphere range scene can be achieved by the projection system, and the total field of view can be extended by increasing the number of the lenses. However, the luminance uniformity in the field-of-view will be influenced by the joint between the lenses. The method of controlling the luminance uniformity of field-of-view is studied in this paper. The needed luminous exitance of each resist array is analyzed. The experiment shows that the new method is applicable for the hardware-in-the-loop simulation test.

Jiang, Zhenyu; Li, Lin; Huang, YiFan

2008-03-01

193

Indoor optical wireless communications: recent developments and future challenges  

Microsoft Academic Search

Wireless communications is facing the challenges of a predicted 'explosion' in the number of wireless devices, demand for higher capacity, and the need to reduce power consumption in order to lower greenhouse gas emissions. Optical Wireless (OW) communications may have a part to play in helping to achieve these aims. High speed line of sight optical wireless systems have the

Dominic O'Brien

2009-01-01

194

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

SciTech Connect

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.

Kim, Hak-Sub; Yoon, Suk-Jin; Chung, Chul; Lee, Sang-Yoon; Lee, Young-Wook [Department of Astronomy and Center for Galaxy Evolution Research, Yonsei University, Seoul 120-749 (Korea, Republic of)] [Department of Astronomy and Center for Galaxy Evolution Research, Yonsei University, Seoul 120-749 (Korea, Republic of); Sohn, Sangmo Tony [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)] [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Kim, Sang Chul [Korea Astronomy and Space Science Institute, Daejeon 305-348 (Korea, Republic of)] [Korea Astronomy and Space Science Institute, Daejeon 305-348 (Korea, Republic of); Kim, Eunhyeuk, E-mail: sjyoon@galaxy.yonsei.ac.kr [Korea Aerospace Research Institute, Daejeon 305-806 (Korea, Republic of)] [Korea Aerospace Research Institute, Daejeon 305-806 (Korea, Republic of)

2013-01-20

195

Wide field-of-view Talbot grid-based microscopy for multicolor fluorescence imaging  

PubMed Central

The capability to perform multicolor, wide field-of-view (FOV) fluorescence microscopy imaging is important in screening and pathology applications. We developed a microscopic slide-imaging system that can achieve multicolor, wide FOV, fluorescence imaging based on the Talbot effect. In this system, a light-spot grid generated by the Talbot effect illuminates the sample. By tilting the excitation beam, the Talbot-focused spot scans across the sample. The images are reconstructed by collecting the fluorescence emissions that correspond to each focused spot with a relay optics arrangement. The prototype system achieved an FOV of 12 × 10 mm2 at an acquisition time as fast as 23 s for one fluorescence channel. The resolution is fundamentally limited by spot size, with a demonstrated full-width at half-maximum spot diameter of 1.2 ?m. The prototype was used to image green fluorescent beads, double-stained human breast cancer SK-BR-3 cells, Giardia lamblia cysts, and the Cryptosporidium parvum oocysts. This imaging method is scalable and simple for implementation of high-speed wide FOV fluorescence microscopy. PMID:23787643

Pang, Shuo; Han, Chao; Erath, Jessey; Rodriguez, Ana; Yang, Changhuei

2013-01-01

196

[A wide-field push-broom hyperspectral imager based on curved prism].  

PubMed

A wide-field pushbroom hyperspectral imager covering short-wavelength infrared range is presented, which can be carried by space borne or airborne platform for remote sensing, acquiring hyperspectral data cube, and analyzing substance compositions and physicochemical properties. Curved prism which simultaneously possesses the functions of dispersion and imaging is used as the prismatic element, and the combination with Offner relay configuration substantially simplifies the design of spectrometer. Compared to conventional dispersive spectral imagers, this design is compact, light-weighted, and small-sized, and can efficiently correct unavoidable spectral line curve (smile) and spectral band (keystone or frown) by prismatic dispersion Compared to grating spectral imagers of the same configuration, the energy utilization efficiency of this design is much higher. The paraxial aberration theory and imaging characteristics of Offner relay configuration is briefly described. The optical layout and image evaluations, including spatial and spectral dimensions, are illustrated respectively, according to Monte Carlo ray-tracing results of seven principal wavelengths. PMID:22870671

Nie, Yun-Feng; Xiangli, Bin; Zhou, Jin-Song; Huang, Min

2012-06-01

197

Telescope Fabra ROA Montsec: A New Robotic Wide Field Baker-Nunn Facility  

NASA Astrophysics Data System (ADS)

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°.40), moderate limiting magnitude (V˜19.5 mag), ability of tracking at arbitrary right ascension (?) and declination (?) 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.

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

2013-05-01

198

Wide field-of-view imaging system using a liquid crystal spatial light modulator  

NASA Astrophysics Data System (ADS)

This paper presents the optical design and experimental demonstration of a compact, foveated, wide field-of-view (FOV) imaging system using two lenses and a liquid crystal spatial light modulator (SLM). The FOV of this simple doublet system is dramatically improved by the SLM, which can be programmed to correct all the geometrical aberrations at any particular field angle. The SLM creates a variation in the image quality across the entire FOV, with a diffraction-limited performance at the field angle of interest (similar to the foveated human vision). The region of interest can be changed dynamically, such that any area within the FOV of the system can be highly resolved within milliseconds. The wide FOV, compactness, and absence of moving parts make this system a good candidate for tracking and surveillance applications. We designed an f/7.7 system, with a 60° full FOV, and a 27 mm effective focal length. Only two lenses and a beam splitter cube were used along with a reflective SLM. The theoretical wavefront aberration coefficients were used to program the SLM, which was placed in the pupil plane of the system. A prototype was built and the system was experimentally demonstrated using monochromatic light and a CCD camera.

Curatu, George; Wick, David V.; Payne, Don M.; Martinez, Ty; Harriman, Jamie; Harvey, James E.

2005-08-01

199

FAINT TIDAL FEATURES IN GALAXIES WITHIN THE CANADA-FRANCE-HAWAII TELESCOPE LEGACY SURVEY WIDE FIELDS  

SciTech Connect

We present an analysis of the detectability of faint tidal features in galaxies from the wide-field component of the Canada-France-Hawaii Telescope Legacy Survey. Our sample consists of 1781 luminous (M{sub r{sup '}}<-19.3 mag) galaxies in the magnitude range 15.5 mag < r' < 17 mag and in the redshift range 0.04 < z < 0.2. Although we have classified tidal features according to their morphology (e.g., streams, shells, and tails), we do not attempt to interpret them in terms of their physical origin (e.g., major versus minor merger debris). Instead, we provide a catalog that is intended to provide raw material for future investigations which will probe the nature of low surface brightness substructure around galaxies. We find that around 12% of the galaxies in our sample show clear tidal features at the highest confidence level. This fraction rises to about 18% if we include systems with convincing, albeit weaker tidal features, and to 26% if we include systems with more marginal features that may or may not be tidal in origin. These proportions are a strong function of rest-frame color and of stellar mass. Linear features, shells, and fans are much more likely to occur in massive galaxies with stellar masses >10{sup 10.5} M {sub Sun }, and red galaxies are twice as likely to show tidal features than are blue galaxies.

Atkinson, Adam M.; Abraham, Roberto G. [Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON M5S 3H4 (Canada)] [Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON M5S 3H4 (Canada); Ferguson, Annette M. N. [Institute for Astronomy, University of Edinburgh, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom)] [Institute for Astronomy, University of Edinburgh, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom)

2013-03-01

200

Demonstration of the Wide-Field Imaging Interferometer Testbed Using a Calibrated Hyperspectral Image Projector  

NASA Technical Reports Server (NTRS)

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.

Bolcar, Matthew R.; Leisawitz, David; Maher, Steve; Rinehart, Stephen

2012-01-01

201

A DEEP, WIDE-FIELD H{alpha} SURVEY OF NEARBY CLUSTERS OF GALAXIES: DATA  

SciTech Connect

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.

Sakai, Shoko [Division of Astronomy and Astrophysics, University of California, Los Angeles, Los Angeles, CA 90095-1562 (United States); Kennicutt, Robert C. Jr. [Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States); Moss, Chris [Astrophysics Research Institute, Liverpool John Moores University, Birkenhead CH41 1LD (United Kingdom)

2012-04-01

202

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

PubMed

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 ?m. 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 ?m 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 attached to a cell-phone could be quite useful especially for resource-limited settings, and might provide an important tool for wide-field imaging and quantification of various lab-on-a-chip assays developed for global health applications, such as monitoring of HIV+ patients for CD4 counts or viral load measurements. PMID:21063582

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

2011-01-21

203

Wide-field computational imaging of pathology slides using lens-free on-chip microscopy.  

PubMed

Optical examination of microscale features in pathology slides is one of the gold standards to diagnose disease. However, the use of conventional light microscopes is partially limited owing to their relatively high cost, bulkiness of lens-based optics, small field of view (FOV), and requirements for lateral scanning and three-dimensional (3D) focus adjustment. We illustrate the performance of a computational lens-free, holographic on-chip microscope that uses the transport-of-intensity equation, multi-height iterative phase retrieval, and rotational field transformations to perform wide-FOV imaging of pathology samples with comparable image quality to a traditional transmission lens-based microscope. The holographically reconstructed image can be digitally focused at any depth within the object FOV (after image capture) without the need for mechanical focus adjustment and is also digitally corrected for artifacts arising from uncontrolled tilting and height variations between the sample and sensor planes. Using this lens-free on-chip microscope, we successfully imaged invasive carcinoma cells within human breast sections, Papanicolaou smears revealing a high-grade squamous intraepithelial lesion, and sickle cell anemia blood smears over a FOV of 20.5 mm(2). The resulting wide-field lens-free images had sufficient image resolution and contrast for clinical evaluation, as demonstrated by a pathologist's blinded diagnosis of breast cancer tissue samples, achieving an overall accuracy of ~99%. By providing high-resolution images of large-area pathology samples with 3D digital focus adjustment, lens-free on-chip microscopy can be useful in resource-limited and point-of-care settings. PMID:25520396

Greenbaum, Alon; Zhang, Yibo; Feizi, Alborz; Chung, Ping-Luen; Luo, Wei; Kandukuri, Shivani R; Ozcan, Aydogan

2014-12-17

204

The development of high-precision hexapod actuators for the Hobby-Eberly Telescope wide field upgrade  

NASA Astrophysics Data System (ADS)

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.

Zierer, Joseph J.; Mock, Jason R.; Beno, Joseph H.; Good, John; Booth, John A.; Lazzarini, Paolo; Fumi, Pierluigi; Anaclerio, Enzo

2010-07-01

205

Pre-Attentive Face Detection for Foveated Wide-Field Surveillance  

Microsoft Academic Search

Abstract: Conventional surveillance sensors suffer from an unavoidabletradeoff between image resolution and field of view.This problem may be overcome by combining a fixed, preattentive,low-resolution wide-field camera with a shiftable,attentive, high-resolution narrow-field camera. Here wepresent techniques for orienting the attentive camera tofaces detected in the pre-attentive wide-field image stream.Unfortunately, the low image resolution of the widefieldsensor precludes the use of most...

Simon Prince; James H. Elder; Yuqian Hou; Mikhail Sizintsev

2005-01-01

206

Extreme Adaptive Optics Testbed: Results and Future Work  

SciTech Connect

'Extreme' adaptive optics systems are optimized for ultra-high-contrast applications, such as ground-based extrasolar planet detection. The Extreme Adaptive Optics Testbed at UC Santa Cruz is being used to investigate and develop technologies for high-contrast imaging, especially wavefront control. A simple optical design allows us to minimize wavefront error and maximize the experimentally achievable contrast before progressing to a more complex set-up. A phase shifting diffraction interferometer is used to measure wavefront errors with sub-nm precision and accuracy. We have demonstrated RMS wavefront errors of <1.3 nm and a contrast of >10{sup -7} over a substantial region using a shaped pupil. Current work includes the installation and characterization of a 1024-actuator Micro-Electro-Mechanical- Systems (MEMS) deformable mirror, manufactured by Boston Micro-Machines, which will be used for wavefront control. In our initial experiments we can flatten the deformable mirror to 1.8-nm RMS wavefront error within a control radius of 5-13 cycles per aperture. Ultimately this testbed will be used to test all aspects of the system architecture for an extrasolar planet-finding AO system.

Evans, J W; Sommargren, G; Poyneer, L; Macintosh, B; Severson, S; Dillon, D; Sheinis, A; Palmer, D; Kasdin, J; Olivier, S

2004-07-15

207

Ground-based astrometry with wide field imagers. V. Application to near-infrared detectors: HAWK-I@VLT/ESO  

NASA Astrophysics Data System (ADS)

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.

Libralato, M.; Bellini, A.; Bedin, L. R.; Piotto, G.; Platais, I.; Kissler-Patig, M.; Milone, A. P.

2014-03-01

208

WIDE-FIELD PRECISION KINEMATICS OF THE M87 GLOBULAR CLUSTER SYSTEM  

SciTech Connect

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.

Strader, Jay [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Romanowsky, Aaron J.; Brodie, Jean P.; Beasley, Michael A.; Arnold, Jacob A. [UCO/Lick Observatory, University of California, Santa Cruz, CA 95064 (United States); Spitler, Lee R. [Center for Astrophysics and Supercomputing, Swinburne University, Hawthorn, VIC 3122 (Australia); Tamura, Naoyuki [Subaru Telescope, National Astronomical Observatory of Japan, Hilo, HI 96720 (United States); Sharples, Ray M. [Department of Physics, University of Durham, South Road, Durham (United Kingdom); Arimoto, Nobuo, E-mail: jstrader@cfa.harvard.edu [National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588 (Japan)

2011-12-01

209

WINGS-SPE Spectroscopy in the WIde-field Nearby Galaxy-cluster Survey  

E-print Network

Aims. We present the results from a comprehensive spectroscopic survey of the WINGS (WIde-field Nearby Galaxy-cluster Survey) clusters, a program called WINGS-SPE. The WINGS-SPE sample consists of 48 clusters, 22 of which are in the southern sky and 26 in the north. The main goals of this spectroscopic survey are: (1) to study the dynamics and kinematics of the WINGS clusters and their constituent galaxies, (2) to explore the link between the spectral properties and the morphological evolution in different density environments and across a wide range in cluster X-ray luminosities and optical properties. Methods. Using multi object fiber fed spectrographs, we observed our sample of WINGS cluster galaxies at an intermediate resolu- tion of 6-9 A and, using a cross-correlation technique, we measured redshifts with a mean accuracy of about 45 km/s. Results. We present redshift measurements for 6137 galaxies and their first analyses. Details of the spectroscopic observations are reported. The WINGS-SPE has about 30% overlap with previously published data sets, allowing us to do both a complete comparison with the literature and to extend the catalogs. Conclusions. Using our redshifts, we calculate the velocity dispersion for all the clusters in the WINGS-SPE sample. We almost trip- licate the number of member galaxies known in each cluster with respect to previous works. We also investigate the X-ray luminosity vs. velocity dispersion relation for our WINGS-SPE clusters, and find it to be consistent with the form Lx proportional to sigma^4.

A. Cava; D. Bettoni; B. M. Poggianti; W. J. Couch; M. Moles; J. Varela; A. Biviano; M. DOnofrio; A. Dressler; G. Fasano; J. Fritz; P. Kjaergaard; M. Ramella; T. Valentinuzzi

2008-12-10

210

Cone of Darkness: Finding Blank-sky Positions for Multi-object Wide-field Observations  

NASA Astrophysics Data System (ADS)

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.

Lorente, N. P. F.

2014-05-01

211

A Light and Effective Wide Field Monitor for Gamma Ray Bursts and Transient Sources  

SciTech Connect

We present here a concept for a light and low-power wide field monitor working in the X-ray range, suitable for simultaneous imaging of large portions of the sky and GRB localizations. Our concept evolves from and improves on the design of the 5-kg SuperAGILE experiment, flying on the AGILE mission and currently delivering arcmin-localizations of GRBs at a rate of about 1/month. Similar to SuperAGILE, our concept is based on position sensitive silicon detectors equipped with one-dimensional coded masks. Different options are available for the detector, whose properties, combined with the scientific requirements, drive the design of the experiment. Our approach is based on a modular detector. The experiment design can then be tailored to specific scientific goals of the experiment or the mission (e.g., to cite GRBs only: the brightest GRBs/XRFs on a large field of view - FoV, or many low-fluence GRBs/XRFs on a smaller FoV, or the low energy spectrum of the prompt event, or the detection of high-z GRBs). In this paper we describe the concept, the main detector properties and outline some possible experiment configurations, with examples of their expected performance. Different experiment configurations in terms of area, FoV, angular resolution may be designed starting from the same detectors. Instead, the band-pass is mostly related to the detector properties. A key point of our project is the high degree of readiness of the detectors that are at production level and may be immediately proposed for a future experiment onboard missions with high readiness requirements.

Feroci, M.; Campana, R.; Costa, E.; Del Monte, E.; Donnarumma, I.; Evangelista, Y.; Lazzarotto, F.; Mastropietro, M.; Muleri, F.; Pacciani, L.; Rubini, A.; Soffitta, P. [INAF-Istituto di Astrofisica Spaziale e Fisica Cosmica-Roma (Italy); Amati, L.; Fuschino, F.; Labanti, C.; Marisaldi, M.; Morelli, E.; Orlandini, M. [INAF-Istituto di Astrofisica Spaziale e Fisica Cosmica-Bologna (Italy); Antonelli, L. A.; Fiore, F. [INAF-Osservatorio Astronomico di Roma-Monteporzio Catone (Italy)] (and others)

2009-05-25

212

Wide-Field Motion Integration in Fly VS Cells: Insights from an Inverse Approach  

PubMed Central

Fly lobula plate tangential cells are known to perform wide-field motion integration. It is assumed that the shape of these neurons, and in particular the shape of the subclass of VS cells, is responsible for this type of computation. We employed an inverse approach to investigate the morphology-function relationship underlying wide-field motion integration in VS cells. In the inverse approach detailed, model neurons are optimized to perform a predefined computation: here, wide-field motion integration. We embedded the model neurons to be optimized in a biologically plausible model of fly motion detection to provide realistic inputs, and subsequently optimized model neuron with and without active conductances (gNa, gK, gK(Na)) along their dendrites to perform this computation. We found that both passive and active optimized model neurons perform well as wide-field motion integrators. In addition, all optimized morphologies share the same blueprint as real VS cells. In addition, we also found a recurring blueprint for the distribution of gK and gNa in the active models. Moreover, we demonstrate how this morphology and distribution of conductances contribute to wide-field motion integration. As such, by using the inverse approach we can predict the still unknown distribution of gK and gNa and their role in motion integration in VS cells. PMID:20957028

Torben-Nielsen, Benjamin; Stiefel, Klaus M.

2010-01-01

213

Negative optical inertia for enhancing the sensitivity of future gravitational-wave detectors  

SciTech Connect

We consider enhancing the sensitivity of future gravitational-wave detectors by using double optical spring. When the power, detuning and bandwidth of the two carriers are chosen appropriately, the effect of the double optical spring can be described as a 'negative inertia', which cancels the positive inertia of the test masses and thus increases their response to gravitational waves. This allows us to surpass the free-mass standard quantum limit (SQL) over a broad frequency band, through signal amplification, rather than noise cancellation, which has been the case for all broadband SQL-beating schemes so far considered for gravitational-wave detectors. The merit of such signal amplification schemes lies in the fact that they are less susceptible to optical losses than noise-cancellation schemes. We show that it is feasible to demonstrate such an effect with the Gingin High Optical Power Test Facility, and it can eventually be implemented in future advanced GW detectors.

Khalili, Farid; Danilishin, Stefan [Faculty of Physics, Moscow State University, Moscow 119991 (Russian Federation); Mueller-Ebhardt, Helge [Max-Planck Institut fuer Gravitationsphysik (Albert-Einstein-Institut) and Leibniz Universitaet Hannover, Callinstr. 38, 30167 Hannover (Germany); Miao Haixing; Zhao Chunnong [School of Physics, University of Western Australia, WA 6009 (Australia); Chen Yanbei [Theoretical Astrophysics 130-33, California Institute of Technology, Pasadena, California 91125 (United States)

2011-03-15

214

MOA-cam3: a wide-field mosaic CCD camera for a gravitational microlensing survey in New Zealand  

E-print Network

We have developed a wide-field mosaic CCD camera, MOA-cam3, mounted at the prime focus of the Microlensing Observations in Astrophysics (MOA) 1.8-m telescope. The camera consists of ten E2V CCD4482 chips, each having 2kx4k pixels, and covers a 2.2 deg^2 field of view with a single exposure. The optical system is well optimized to realize uniform image quality over this wide field. The chips are constantly cooled by a cryocooler at -80C, at which temperature dark current noise is negligible for a typical 1-3 minute exposure. The CCD output charge is converted to a 16-bit digital signal by the GenIII system (Astronomical Research Cameras Inc.) and readout is within 25 seconds. Readout noise of 2--3 ADU (rms) is also negligible. We prepared a wide-band red filter for an effective microlensing survey and also Bessell V, I filters for standard astronomical studies. Microlensing studies have entered into a new era, which requires more statistics, and more rapid alerts to catch exotic light curves. Our new system is a powerful tool to realize both these requirements.

T. Sako; T. Sekiguchi; M. Sasaki; K. Okajima; F. Abe; I. A. Bond; J. B. Hearnshaw; Y. Itow; K. Kamiya; P. M. Kilmartin; K. Masuda; Y. Matsubara; Y. Muraki; N. J. Rattenbury; D. J. Sullivan; T. Sumi; P. Tristram; T. Yanagisawa; P. C. M. Yock

2008-04-04

215

Software\\/hardware defined network (SHINE): A novel adaptive optical network framework for future internet  

Microsoft Academic Search

A novel Software\\/Hardware defIned NEtwork (SHINE) framework for future optical network is proposed in this paper. An FPGA based SHINE adaptive network element (SANE) carrying time shared optical network (TSON) service and 10G Ethernet service is implemented. A cross-platform C++\\/Qt based SHINE IDE incorporating fine\\/coarse granular instruction set is developed to simply compose node\\/network manually or automatically. Five types of

Yixuan Qin; Yan; Georgios S. Zervas; Bijan R. Rofoee; Norberto Amaya; Dimitra Simeonidou

2012-01-01

216

Extreme AO: The future of high-contrast imaging with adaptive optics  

Microsoft Academic Search

Title: Extreme AO: The future of high-contrast-imaging with adaptive optics. Adaptive optics (AO) partially cancels wavefront aberrations caused by atmospheric turbulence and can allow ground-basd telescope to reach their full diffraction-limited resolution. A fundamental limitation of all AO systems is that they have little effect on the atmospheric scattered light halo beyond a control radius roughly given by the wavelength

B. Macintosh

2001-01-01

217

THE FIRST HUNDRED BROWN DWARFS DISCOVERED BY THE WIDE-FIELD INFRARED SURVEY EXPLORER (WISE)  

SciTech Connect

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 these objects and discuss constraints on both the functional form of the mass function and the low-mass limit of star formation.

Davy Kirkpatrick, J.; Gelino, Christopher R.; Griffith, Roger L.; Marsh, Kenneth A.; Tsai, Chao-Wei; Beichman, Charles A. [Infrared Processing and Analysis Center, MS 100-22, California Institute of Technology, Pasadena, CA 91125 (United States); Cushing, Michael C.; Mainzer, A.; Eisenhardt, Peter R.; Bauer, James M. [NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Skrutskie, Michael F. [Department of Astronomy, University of Virginia, Charlottesville, VA 22904 (United States); Wright, Edward L.; McLean, Ian S.; Lake, Sean E.; Petty, Sara M. [Department of Physics and Astronomy, UCLA, Los Angeles, CA 90095-1547 (United States); Thompson, Maggie A. [The Potomac School, 1301 Potomac School Road, McLean, VA 22101 (United States); Benford, Dominic J. [Infrared Astrophysics Branch, NASA-Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, MD 20771 (United States); Bridge, Carrie R. [Division of Physics, Mathematics, and Astronomy, MS 220-6, California Institute of Technology, Pasadena, CA 91125 (United States); Stanford, S. A. [Department of Physics, University of California, Davis, CA 95616 (United States); Bailey, Vanessa, E-mail: davy@ipac.caltech.edu [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); and others

2011-12-01

218

The WSRT wide-field H I survey. I. The background galaxy sample  

NASA Astrophysics Data System (ADS)

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 uncataloged low mass companions. We use our galaxy sample to estimate the H I mass function from our survey volume. Good agreement is found with the HIPASS BGC results, but only after explicit correction for galaxy density variations with distance. Table 1 is only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/406/829 and Fig. 3 is only available in electronic form at http://www.edpsciences.org

Braun, R.; Thilker, D.; Walterbos, R. A. M.

2003-08-01

219

Center for Applied Optics Studies: an investment in Indiana's future  

NASA Astrophysics Data System (ADS)

To understand the involvement of the State of Indiana with the Center for Applied Optics at Rose-Hulman Institute of Technology, it is best to start with an explanation of the Indiana Corporation for Science and Technology (CST), its basic charter and its programs. Established in 1982 as a private not-for-profit corporation, CST was formed to promote economic development within the State of Indiana. Two programs that were initially a part of CST's charter and supported with state dollars were a seed capital investment program, aimed at developing new products and processes, and the establishment of university centers of technology development. The former was conceived to create jobs and new, technologically advanced industries in Indiana. The latter was an attempt to encourage technology transfer from the research laboratories of the state universities to the production lines of Indiana industry. Recently, CST has undergone a name change to the Indiana Business Modernization and Technology Corporation (BMT) and adopted an added responsibility of proactive assistance to small- and medium-sized businesses in order to enhance the state's industrial competitiveness.

Schuh, Delbert J., II; Khorana, Brij M.

1992-05-01

220

Probing other solar systems with current and future adaptive optics  

SciTech Connect

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.

Macintosh, B; Marois, C; Phillion, D; Poyneer, L; Graham, J; Zuckerman, B; Gavel, D; Veran, J; Wilhelmsen-Evans, J; Mellis, C

2008-09-08

221

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)

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.

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

222

The Status of NASA's Wide-Field Meteor Camera Network and Preliminary Results  

NASA Technical Reports Server (NTRS)

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.

Blaauw, R.; Cooke, W.; Kingery, A.; Suggs, R.

2014-01-01

223

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...

224

The First Hundred Brown Dwarfs Discovered by the Wide-field Infrared Survey Explorer (WISE)  

E-print Network

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 ...

Bochanski, John J.

225

The WSRT wide-field HI survey: I. The background galaxy sample  

E-print Network

We have used the Westerbork array to carry out an unbiased wide-field survey for HI emission features, achieving an RMS sensitivity of about 18 mJy/Beam at a velocity resolution of 17 km/s over 1800 deg^2 and between -1000 BGC results, but only after explicit correction for galaxy density variations with distance.

Robert Braun; David Thilker; Rene Walterbos

2003-05-21

226

Preliminary design of the Wide-Field Infrared Survey Explorer (WISE)  

Microsoft Academic Search

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.

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

2005-01-01

227

Saturn's hydrogen aurora: Wide field and planetary camera 2 imaging from the Hubble Space Telescope  

Microsoft Academic Search

Wide field and planetary camera 2\\/Hubble Space Telescope (WFPC2\\/HST) images of Saturn's far ultraviolet aurora reveal emissions confined to a narrow band of latitudes near Saturn's north and south poles. The aurorae are most prominent in the morning sector with patterns that appear fixed in local time. The geographic distribution and vertical extent of the auroral emissions seen in these

John T. Trauger; John T. Clarke; Gilda E. Ballester; Robin W. Evans; Christopher J. Burrows; David Crisp; John S. Gallagher; Richard E. Griffiths; J. Jeff Hester; John G. Hoessel; Jon A. Holtzman; John E. Krist; Jeremy R. Mould; Raghvendra Sahai; Paul A. Scowen; Karl R. Stapelfeldt; Alan M. Watson

1998-01-01

228

Astronaut Jeffrey Hoffman with Wide Field/Planetary Camera during EVA  

NASA Technical Reports Server (NTRS)

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).

1993-01-01

229

Active Pixel Xray Sensor Technology Development for the GenerationX WideField Imager  

E-print Network

Active Pixel Xray Sensor Technology Development for the GenerationX WideField Imager A White for and benefits of a targeted program to develop Active Pixel Sensor (APS) detector technology for use sensor technology. We show how a properly planned program to develop this technology for Generation

230

Mid-Infrared Selected AGN from the Wide-field Infrared Survey Explorer (WISE)  

NASA Astrophysics Data System (ADS)

We request funding for a comprehensive investigation of active galactic nuclei (AGN) identified with the Wide-field Infrared Survey Explorer (WISE). Most surveys for AGN are severely biased towards unobscured, or type-1 AGN. Nuclear emission in such sources dominates over host galaxy light at most wavelengths, making type-1 AGN both more readily identifiable and easier to follow-up spectroscopically. However, models predict that obscured, or type-2 AGN outnumber type-1 AGN by a factor of a few. This population has been poorly studied to date, but are readily identifiable at both mid- infrared wavelengths and in the high-energy (>10 keV) X-rays. We have identified a simple, highly reliable mid-infrared color selection for AGN, both obscured and unobscured, using WISE. We find ~60 AGN candidates per square degree, implying ~2.5 million AGN across the full sky. The AGN luminosities are comparable to Sloan Digital Sky Survey quasars, but with a source density ~3x greater. We request funding for five distinct investigations of WISE-selected AGN: (1) We will study how obscuration depends on redshift and luminosity using a sample of ~1000 WISE-selected AGN in the Bootes field. This studiy will probe AGN unification models, particularly the receding torus model. (2) We will measure AGN clustering as a function of obscuration using large samples of WISE-selected AGN in the SDSS area. Such analysis will derive host halo mass as a function of obscuration, thereby probing both the role of AGN and AGN feedback in galaxy evolution as well as AGN unification models. (3) We will analyze Suzaku data on one extreme WISE-selected source at z~2 which we observed in Cycle 7. (4) Using a large sample of WISE-selected AGN with well characterized X-ray columns, N(H), and reddening, A(V), we will update the gas to dust relation for luminous obscured and unobscured AGN, studying how it depends on reddening, luminosity and redshift. Finally, (5) we will use mid-infrared data from WISE as a unique and powerful tool for probing dual AGN candidates, systems which are thought likely to host multiple active nuclei based on optical spectroscopy. Such systems are important sources for gravitational waves, but significant concerns exist that many of these sources host a single AGN with a complex narrow-line region. Mid-infrared data has proved important in detailed studies of a few individual dual AGN; we request funding here for a systematic study of the entire sample of several hundred published dual AGN candidates in SDSS.

Stern, Daniel

231

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

NASA Technical Reports Server (NTRS)

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 either electron excitation (SEM-EDS) and, in a minority of cases for cores assessed as "difficult" targets, proton excitation (IBA). All samples were documented by electron imagery: backscattered electron imagery in the SEM, and where appropriate, secondary electron imagery during IBA.

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

232

Active wide-field illumination for high-throughput fluorescence lifetime imaging  

PubMed Central

Wide-field fluorescence lifetime imaging allows for fast imaging of large sample areas at the cost of low sensitivity to weak fluorescence signals. To overcome this challenge, we developed an active wide-field illumination (AWFI) strategy to optimize the impinging spatial intensity for acquiring optimal fluorescence signals over the whole sample. We demonstrated the ability of AWFI to accurately estimate lifetimes from a multiwell plate sample with concentrations ranging over two orders of magnitude. We further reported its successful application to a quantitative Förster resonance energy transfer lifetime cell-based assay. Overall, this method allows for enhanced accuracy in lifetime-based imaging at high acquisition speed over samples with large fluorescence intensity distributions. PMID:24081103

Zhao, Lingling; Abe, Ken; Barroso, Margarida; Intes, Xavier

2014-01-01

233

Optimal proper motion measurements with the Wide Field and Planetary Camera  

E-print Network

An optimal maximum-likelihood technique for computing point-source image centroids from many, slightly offset, CCD frames is presented. The method is especially useful for measuring stellar proper motions from data taken with the Wide Field and Planetary Camera aboard the HST, and also provides a means to identify very compact non-stellar sources. We work though the example problem of obtaining image centroids of objects in the Hubble Deep Field.

Rodrigo Ibata; Geraint Lewis

1998-09-07

234

Wide Field Observations of the Ursa Minor dSph galaxy  

E-print Network

Ursa Minor (UMi) is one of the closest satellites of the Milky Way (d=69 kpc). It is possibly a disrupted dSph interacting with the external Galactic halo. This makes its study quite necessary in the forementioned context. In this paper we present preliminary results of a wide field photometry survey of UMi and discuss the presence of an intermediate-age population and tidal tails in it.

D. Martinez-Delgado; A. Aparicio

1999-04-28

235

Hubble Space Telescope: Wide field and planetary camera instrument handbook. Version 2.1  

NASA Technical Reports Server (NTRS)

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.

Griffiths, Richard (editor)

1990-01-01

236

The WSRT wide-field H I survey. I. The background galaxy sample  

Microsoft Academic Search

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,

R. Braun; D. Thilker; R. A. M. Walterbos

2003-01-01

237

Are there any isolated old neutron stars in the ROSAT Wide Field Camera survey?  

Microsoft Academic Search

We present the results of Monte Carlo simulations to predict the number of isolated old neutron stars (IONs) that are observed in the ROSAT Wide Field Camera (WFC) survey as a result of accretion-powered extreme ultraviolet (EUV) emission. Magnetic field strengths of 10^9 to 10^12 G are considered along with different models for the local interstellar medium. The most recent

R. A. Manning; R. D. Jeffries; A. P. Willmore

1996-01-01

238

Wide Field Infrared Survey Telescope [WFIRST]: Telescope Design and Simulated Performance  

NASA Technical Reports Server (NTRS)

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.

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

239

Liquid Lens module with wide field-of-view and variable focal length  

Microsoft Academic Search

A novel wide angle and variable-focus imaging module based on a miniaturized liquid lens is presented for capsule endoscopy\\u000a applications. For these applications, it is desirable to have features such as a wide field of view (FOV), variable focus,\\u000a small size, and low power consumption, thereby taking full advantage of the miniaturized liquid lens. The proposed imaging\\u000a module has three

Sang Won Seo; Seungoh Han; Jun Ho Seo; Woo Bum Choi; Man Young Sung

2010-01-01

240

Encoding wide-field motion and direction in the central complex of the cockroach Blaberus discoidalis.  

PubMed

In the arthropod brain, the central complex (CX) receives various forms of sensory signals and is associated with motor functions, but its precise role in behavior is controversial. The optomotor response is a highly conserved turning behavior directed by visual motion. In tethered cockroaches, 20% procaine injected into the CX reversibly blocked this behavior. We then used multichannel extracellular recording to sample unit activity in the CX in response to wide-field visual motion stimuli, moving either horizontally or vertically at various temporal frequencies. For the 401 units we sampled, we identified five stereotyped response patterns: tonically inhibited or excited responses during motion, phasically inhibited or excited responses at the initiation of motion, and phasically excited responses at the termination of motion. Sixty-seven percent of the units responded to horizontal motion, while only 19% responded to vertical motion. Thirty-eight percent of responding units were directionally selective to horizontal motion. Response type and directional selectivity were sometimes conditional with other stimulus parameters, such as temporal frequency. For instance, 16% of the units that responded tonically to low temporal frequencies responded phasically to high temporal frequencies. In addition, we found that 26% of wide-field motion responding units showed a periodic response that was entrained to the temporal frequency of the stimulus. Our results show a diverse population of neurons within the CX that are variably tuned to wide-field motion parameters. Our behavioral data further suggest that such CX activity is required for effective optomotor responses. PMID:25278467

Kathman, Nicholas D; Kesavan, Malavika; Ritzmann, Roy E

2014-11-15

241

VizieR Online Data Catalog: Catalogue of Wide-Field Plate Archives (Tsvetkova+ 2008)  

NASA Astrophysics Data System (ADS)

The Catalogue of Wide-Field Plate Archives (CWFPAs, version 5.2 from July 2008) contains the information for 440 plate archives stored in astronomical observatories and institutions all over the world. It is an integrated part of the Wide-Field Plate Database (WFPDB) aiming to store the valuable astronomical plate observations (more than 2,200,000 wide-field plates or films) and quickly to offer the opportunity to see back in time records of interesting astronomical phenomena. The Catalogue provides information for the location (storage) of the plate archives - site and country; for the observatory, where the archive was made - name, site, country, Marsden's number, time zone, coordinates and altitude; for the archive instrument - original name, clear aperture, mirror diameter, focal length, scale, type, field size and years of operation; for the number of direct and objective prism plates; for the archive type, quality and the name of astronomer in charge for possible contacts. Search for plate archives can be made using the WFPDB instrument identifier (equal to archive identifier), which constitutes from the WFPDB observatory identifier, instrument aperture, and possible suffix to the instrument identifier in the cases when more instruments with the same aperture exist in the observatory. (1 data file).

Tsvetkova, K.; Tsvetkov, M.

2008-10-01

242

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

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.

Rutkowski, M. J.; Cohen, S. H.; Windhorst, R. A. [School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287-1404 (United States); Kaviraj, S.; Crockett, R. M.; Silk, J. [Department of Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH (United Kingdom); O'Connell, R. W. [Department of Astronomy, University of Virginia, P.O. Box 3818, Charlottesville, VA 22903 (United States); Hathi, N. P.; McCarthy, P. J. [Observatories of the Carnegie Institute of Washington, Pasadena, CA 91101 (United States); Ryan, R. E. Jr.; Koekemoer, A.; Bond, H. E. [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Yan, H. [Center for Cosmology and Astroparticle Physics, Ohio State University, Columbus, OH 43210 (United States); Kimble, R. A. [NASA-Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Balick, B. [Department of Astronomy, University of Washington, Seattle, WA 98195-1580 (United States); Calzetti, D. [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States); Disney, M. J. [School of Physics and Astronomy, Cardiff University, Cardiff CF24 3AA (United Kingdom); Dopita, M. A. [Research School of Physics and Astronomy, The Australian National University, ACT 2611 (Australia); Frogel, J. A. [Astronomy Department, King Abdulaziz University, P.O. Box 80203, Jeddah (Saudi Arabia); Hall, D. N. B. [Institute for Astronomy, University of Hawaii, Honolulu, HI 96822 (United States); and others

2012-03-01

243

The globular cluster system of NGC 1316. I. Wide-field photometry in the Washington system  

NASA Astrophysics Data System (ADS)

Context. NGC 1316 (Fornax A) is a prominent merger remnant in the outskirts of the Fornax cluster. The bulge stellar population of NGC 1316 has a strong intermediate-age component. Studies of its globular cluster system may help to further refine its probably complex star formation history. Aims: The cluster system has not yet been studied in its entirety. We therefore present a wide-field study of the globular cluster system of NGC 1316, investigating its properties in relation to the global morphology of NGC 1316. Methods: We used the MOSAIC II camera at the 4-m Blanco telescope at CTIO in the filters Washington C and Harris R. We identified globular cluster candidates and studied their color distribution and the structural properties of the system. In an appendix, we also remark on the morphology, present color maps, and present new models for the brightness and color profiles of the galaxy. Results: The cluster system is well confined to the optically visible outer contours of NGC 1316. There are about 640 cluster candidates down to R = 24 mag. The color distribution of the entire sample is unimodal, but the color distribution of bright subsamples in the bulge shows two peaks that, compared with theoretical Washington colors with solar metallicity, correspond to ages of about 2 Gyr and 0.8 Gyr, respectively. We also find a significant population of clusters in the color range 0.8 < C - R < 1.1, which must be populated by clusters younger than 0.8 Gyr, unless they are very metal-poor. The color interval 1.3 < C - R < 1.6 hosts the bulk of intermediate-age clusters, which show a surface density profile with a sharp decline at about 4'. The outer cluster population shows an unimodal color distribution with a peak at C - R = 1.1, indicating a higher contribution of old, metal-poor clusters. However, their luminosity function does not show the expected turn-over, so the fraction of younger clusters is still significant. We find a pronounced concentration of blue cluster candidates in the area of Schweizer's L1-structure. Conclusions: Cluster formation in NGC 1316 has continued after an initial burst that is presumably related to the main merger. A toy model with two bursts of ages 2 Gyr and 0.8 Gyr is consistent with photometric properties and dynamical M/L-values. In this model, the older, metal-rich pre-merger population has an age of 7 Gyr, contributes 90% of the bulge mass and 70% of the luminosity. Its properties are consistent with spiral galaxies, where star-bursts were triggered by major/minor mergers and/or close encounters. Based on observations obtained at the Cerro Tololo Inter-American Observatory, Chile.Appendix is available in electronic form at http://www.aanda.orgThe photometric data are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/543/A131

Richtler, T.; Bassino, L. P.; Dirsch, B.; Kumar, B.

2012-07-01

244

Utilization of a Curved Focal Surface Array in a 3.5m Wide Field of View Telescope  

NASA Astrophysics Data System (ADS)

Wide field of view optical telescopes have a range for uses in both the astronomical and space surveillance purposes. In designing these systems, a number of factors must be taken into account and design trades accomplished to best balance the performance and cost of the system to meet various program constraints. One design trade that has been discussed of the past decade is the curving of the digital focal surface array to meet the field curvature versus the utilization of optical elements to flatten the field curvature for a more traditional focal plane array. For the Defense Advanced Research Projects Agency (DARPA) 3.5m Space Surveillance Telescope (SST) the choice was made to curve the array to best satisfy the stressing telescope performance parameters, along with programmatic challenges. The results of this design choice led to a system that meets all of the initial program goals and stands ready to dramatically improve the nation's space surveillance capabilities. This paper will discuss the implementation of the curved focal surface array, the performance achieved by the array and the delta cost difference in the curved array versus a typical flat array.

Blake, T.; Faccenda, W.; Lambour, R.; Shah, R.; Smith, A.; Gregory, J. G.; Pearce, E. C.; Woods, D.; Sundbeck, S.; Bolden, M.

2013-09-01

245

The optical antenna system design research on earth integrative network laser link in the future  

NASA Astrophysics Data System (ADS)

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 reference value in engineering. It can provide effective technical support to realize interconnection of earth integrated laser link information network in the future.

Liu, Xianzhu; Fu, Qiang; He, Jingyi

2014-11-01

246

The First Hundred Brown Dwarfs Discovered by the Wide-Field Infrared Survey Explorer (WISE)  

NASA Technical Reports Server (NTRS)

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. "

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

247

Sherlock: An Automated Follow-Up Telescope for Wide-Field Transit Searches  

E-print Network

The most significant challenge currently facing photometric surveys for transiting gas-giant planets is that of confusion with eclipsing binary systems that mimic the photometric signature. A simple way to reject most forms of these false positives is high-precision, rapid-cadence monitoring of the suspected transit at higher angular resolution and in several filters. We are currently building a system that will perform higher-angular-resolution, multi-color follow-up observations of candidate systems identified by Sleuth (our wide-field transit survey instrument at Palomar), and its two twin system instruments in Tenerife and northern Arizona.

Lewis Kotredes; David Charbonneau; Dagny L. Looper; Francis T. O'Donovan

2003-12-16

248

Quantitative phase microscopy of articular chondrocyte dynamics by wide-field digital interferometry  

PubMed Central

We experimentally implement label-free phase microscopy using wide-field digital interferometry (WFDI) techniques to retrieve quantitative volumetric data of articular chondrocyte dynamics. Using the scanless interferometric system, we visualize chondrocyte swelling and bursting induced by hypo-osmotic pressure. Reconstructed images are obtained by an efficient digital process. We use the resulting images to calculate quantitative temporal-spatial morphological parameters of the cell, with the observed dynamics limited only by the true frame rate of the camera. To show the utility of WFDI in recording articular chondrocyte dynamics, we also provide an experimental comparison of WFDI and differential interference contrast microscopy. PMID:20210420

Shaked, Natan T.; Finan, John D.; Guilak, Farshid; Wax, Adam

2010-01-01

249

The WSRT wide-field HI survey: I. The background galaxy sample  

Microsoft Academic Search

We have used the Westerbork array to carry out an unbiased wide-field survey\\u000afor HI emission features, achieving an RMS sensitivity of about 18 mJy\\/Beam at\\u000aa velocity resolution of 17 km\\/s over 1800 deg^2 and between\\u000a-1000 < V_Hel<+6500 km\\/s. The primary data consists of auto-correlation spectra\\u000awith an effective angular resolution of 49' FWHM. We detect 155 external

Robert Braun; David Thilker; Rene A. M. Walterbos

2003-01-01

250

Space-bandwidth scaling for wide field-of-view imaging.  

PubMed

We examine the space-bandwidth product of wide field-of-view imaging systems as the systems scale in size. Our analysis is based on one conducted to examine the behavior of a plano-convex lens imaging onto a flat focal geometry. We extend this to consider systems with monocentric lenses and curved focal geometries. As a means to understand system cost, and not just performance, we also assess the volume and mass associated with these systems. Our analysis indicates monocentric lenses imaging onto a curved detector outperform other systems for the same design constraints but do so at a cost in lens weight. PMID:22307128

Milojkovic, Predrag; Mait, Joseph N

2012-02-01

251

On the Design of Wide-Field X-ray Telescopes  

NASA Technical Reports Server (NTRS)

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.

Elsner, Ronald F.; O'Dell, Stephen L.; Ramsey, Brian D.; Weiskopf, Martin C.

2009-01-01

252

Wide-field-of-view foveated imaging system using a liquid crystal spatial light modulator  

NASA Astrophysics Data System (ADS)

We have successfully demonstrated a simple, wide field-of- view, foveated imaging system utilizing a liquid crystal spatial light modulator (SLM). The SLM was used to correct the off-axis aberrations that otherwise limited the useful field-of-view (FOV) of our system. Our system mimics the operation of the human eye by creating an image with variable spatial resolution and could be made significantly smaller and more compact than a conventional wide FOV system. It may be useful in applications such as surveillance, remote navigation of unmanned vehicles, and target acquisition and tracking, or any application where size, weight, or data transmission bandwidth is critical.

Wick, David V.; Martinez, Ty; Baker, Jeffrey T.; Payne, Don M.; Stone, Bradley R.; Restaino, Sergio R.

2002-07-01

253

Wide-field in vivo background free imaging by selective magnetic modulation of nanodiamond fluorescence  

PubMed Central

The sensitivity and resolution of fluorescence-based imaging in vivo is often limited by autofluorescence and other background noise. To overcome these limitations, we have developed a wide-field background-free imaging technique based on magnetic modulation of fluorescent nanodiamond emission. Fluorescent nanodiamonds are bright, photo-stable, biocompatible nanoparticles that are promising probes for a wide range of in vitro and in vivo imaging applications. Our readily applied background-free imaging technique improves the signal-to-background ratio for in vivo imaging up to 100-fold. This technique has the potential to significantly improve and extend fluorescent nanodiamond imaging capabilities on diverse fluorescence imaging platforms. PMID:24761300

Sarkar, Susanta K.; Bumb, Ambika; Wu, Xufeng; Sochacki, Kem A.; Kellman, Peter; Brechbiel, Martin W.; Neuman, Keir C.

2014-01-01

254

Micrometeoroid Impacts on the Hubble Space Telescope Wide Field and Planetary Camera 2: Larger Particles  

NASA Technical Reports Server (NTRS)

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.

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

255

Wide Field Camera 3: A Powerful New Imager for the Hubble Space Telescope  

NASA Technical Reports Server (NTRS)

Wide Field Camera 3 (WFC3) is a powerful UV/visible/near-infrared camera in development for installation into the Hubble Space Telescope during upcoming Servicing Mission 4. WFC3 provides two imaging channels. The UVIS channel incorporates a 4096 x 4096 pixel CCD focal plane with sensitivity from 200 to 1000 nm. The IR channel features a 1024 x 1024 pixel HgCdTe focal plane covering 850 to 1700 nm. We report here on the design of the instrument, the performance of its flight detectors, results of the ground test and calibration program, and the plans for the Servicing Mission installation and checkout.

Kimble, Randy

2008-01-01

256

Far ultraviolet wide field imaging and photometry - Spartan-202 Mark II Far Ultraviolet Camera  

NASA Technical Reports Server (NTRS)

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.

Carruthers, George R.; Heckathorn, Harry M.; Opal, Chet B.; Witt, Adolf N.; Henize, Karl G.

1988-01-01

257

Far ultraviolet wide field imaging with a SPARTAN /Experiment of Opportunity/ Payload  

NASA Technical Reports Server (NTRS)

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.

Carruthers, G. R.; Heckathorn, H. M.; Opal, C. B.

1982-01-01

258

Future Optical Access Network and Spectral M-Ary ASK OCDM as Its Key Technology  

NASA Astrophysics Data System (ADS)

This paper presents spectral multi-level (M-ary) amplitude shift keying (ASK) optical code-division-multiplexing (OCDM) as a key technology for future optical access network. A novel transmitter configuration to achieve flexible scalability that is required in future optical access network is proposed. The transmitter employs pre-biasing circuits and dummy data input. Pre-biasing circuits enable us to achieve high tolerance to multiple access interference by compensating for the nonlinearity of the M-ary ASK and increase the number of multiplexed binary data streams. By inputting the dummy data into the transmitter so that the total number of multiplexed binary data streams including those that actually accommodate users/services and the dummy streams remains constant, the number of users/services can be increased up to the total number of data streams without changing the parameters for pre-biasing. Therefore, the proposed transmitter can flexibly enhance the scalability of the spectral M-ary ASK OCDM. The formulas for calculating the bit error rate characteristics are described when using the conventional and proposed transmitters. The feasibility of the proposed transmitter is verified theoretically using the established formulas.

Kaneko, Shin; Miki, Noriki; Kimura, Hideaki; Hadama, Hisaya

259

Design and implementation of coating hardware for the Hobby-Eberly Telescope wide-field corrector  

NASA Astrophysics Data System (ADS)

A major upgrade of the HET is in progress that will substantially increase the pupil size to 10 meters and the field of view to 22 arc-minutes by replacing the spherical aberration corrector. The new Wide Field Corrector is a 4-element assembly weighing 750kg and measuring 1.34 meters diameter by 2.1 meter in length. Special fixtures were required in order to support the mirrors of the Wide-Field Corrector and adapt them to the coaters chamber, during the vacuum coating process. For the 1 meter-class mirrors, the only suitable support interface was located on a 80mm wide cylindrical surface on the periphery of each mirror. The vacuum compatible system had to support the mirrors with the surface facing downward, and accommodate thermal ranges from ambient to 100C without inducing stresses in the substrate. The fixture also had to accommodate washing, as well as support of witness samples during testing and production runs, and provide masking for alignment fixtures in the center apertures of each mirror. Design principles, materials, implementation details, as well as lessons learned are covered*.

Good, John; Lee, Hanshin; Hill, Gary J.; Vattiat, Brian; Perry, David; Kriel, Herman; Savage, Richard

2014-07-01

260

Hubble Space Telescope Spectroscopy of Brown Dwarfs Discovered with the Wide-field Infrared Survey Explorer  

E-print Network

We present a sample of brown dwarfs identified with the {\\it Wide-field Infrared Survey Explorer} (WISE) for which we have obtained {\\it Hubble Space Telescope} ({\\it HST}) Wide Field Camera 3 (WFC3) near-infrared grism spectroscopy. The sample (twenty-two in total) was observed with the G141 grism covering 1.10$-$1.70 $\\mu$m, while fifteen were also observed with the G102 grism, which covers 0.90$-$1.10 $\\mu$m. 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 nineteenth, twentieth, and twenty-first spec...

Schneider, Adam 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

2015-01-01

261

Astro-WISE Processing of Wide-field Images and Other Data  

NASA Astrophysics Data System (ADS)

Astro-WISE (Vriend et al. 2012) is the Astronomical Wide-field Imaging System for Europe (Valentijn et al. 2007). It is a scientific information system which consists of hardware and software federated over about a dozen institutes throughout Europe. It has been developed to exploit the ever increasing avalanche of data produced by astronomical surveys and data intensive scientific experiments in general. The demo explains the architecture of the Astro-WISE information system and shows the use of Astro-WISE interfaces. Wide-field astronomical images are derived from the raw image to the final catalog according to the user's request. The demo is based on the standard Astro-WISE guided tour, which can be accessed from the Astro-WISE website. The typical Astro-WISE data processing chain is shown, which can be used for data handling for a variety of different instruments, currently 14, including OmegaCAM, MegaCam, WFI, WFC, ACS/HST, etc.

Buddelmeijer, H.; Williams, O. R.; McFarland, J. P.; Belikov, A.

2012-09-01

262

An Ultra Fast Image Generator (UFIG) for wide-field astronomy  

NASA Astrophysics Data System (ADS)

Simulated wide-field images are becoming an important part of observational astronomy, either to prepare for new surveys or to test measurement methods. In order to efficiently explore vast parameter spaces, the computational speed of simulation codes is a central requirement to their implementation. We introduce the Ultra Fast Image Generator (UFIG) which aims to bring wide-field imaging simulations to the current limits of computational capabilities. We achieve this goal through: (1) models of galaxies, stars and observational conditions, which, while simple, capture the key features necessary for realistic simulations, and (2) state-of-the-art computational and implementation optimizations. We present the performances of UFIG and show that it is faster than existing public simulation codes by several orders of magnitude. It allows us to produce images more quickly than SEXTRACTOR needs to analyze them. For instance, it can simulate a typical 0.25 deg2 Subaru SuprimeCam image (10k×8k pixels) with a 5-? limiting magnitude of R=26 in 30 s on a laptop, yielding an average simulation time for a galaxy of 30 ?s. This code is complementary to end-to-end simulation codes and can be used as a fast, central component of observational methods relying on simulations. For instance, it can be used to efficiently calibrate high-precision measurements, as recently suggested for cosmic shear.

Bergé, Joel; Gamper, Lukas; Réfrégier, Alexandre; Amara, Adam

2013-02-01

263

The Challenge of Wide-Field Transit Surveys: The Case of GSC 01944-02289  

E-print Network

Wide-field searches for transiting extra-solar giant planets face the difficult challenge of separating true transit events from the numerous false positives caused by isolated or blended eclipsing binary systems. We describe here the investigation of GSC 01944-02289, a very promising candidate for a transiting brown dwarf detected by the Transatlantic Exoplanet Survey (TrES) network. The photometry and radial velocity observations suggested that the candidate was an object of substellar mass in orbit around an F star. However, careful analysis of the spectral line shapes revealed a pattern of variations consistent with the presence of another star whose motion produced the asymmetries observed in the spectral lines of the brightest star. Detailed simulations of blend models composed of an eclipsing binary plus a third star diluting the eclipses were compared with the observed light curve and used to derive the properties of the three components. Our photometric and spectroscopic observations are fully consistent with a blend model of a hierarchical triple system composed of an eclipsing binary with G0V and M3V components in orbit around a slightly evolved F5 dwarf. We believe that this investigation will be helpful to other groups pursuing wide-field transit searches as this type of false detection could be more common than true transiting planets, and difficult to identify.

Georgi Mandushev; Guillermo Torres; David W. Latham; David Charbonneau; Roi Alonso; Russel J. White; Robert P. Stefanik; Edward W. Dunham; Timothy M. Brown; Francis T. O'Donovan

2005-01-25

264

Using Wide-Field Meteor Cameras to Actively Engage Students in Science  

NASA Astrophysics Data System (ADS)

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.

Kuehn, D. M.; Scales, J. N.

2012-08-01

265

NASA's Challenges in Optics for Future Space-Based Science Missions  

NASA Technical Reports Server (NTRS)

NASA's mission is: "To understand and project our home planet, To explore the universe and search for life, To inspire the next generation of explorers ... as only NASA can." These mission concepts are further defined in our recently published"Strategic Objectives for 2005 and Beyond" , which include conducting advanced telescope searches for Earth-like planets and habitable environments around the stars, as well as exploring the universe to understand its origin, structure, evolution, and destiny. This presentation will summarize several future space-based missions currently in formulation to meet these objectives, and will outline some of the principal challenges in the field of optics to their success.

Stahl, H. Phil

2005-01-01

266

Wide-field imaging and flow cytometric analysis of cancer cells in blood by fluorescent nanodiamond labeling and time gating  

NASA Astrophysics Data System (ADS)

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.

Hui, Yuen Yung; Su, Long-Jyun; Chen, Oliver Yenjyh; Chen, Yit-Tsong; Liu, Tzu-Ming; Chang, Huan-Cheng

2014-07-01

267

Lessons Learned from the Wide Field Camera 3 TV1 and TV2 Thermal Vacuum Test Campaigns  

NASA Technical Reports Server (NTRS)

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.

Peabody, Hume; Stavely, Richard; Bast, William

2008-01-01

268

The 2MASS Wide-Field T Dwarf Search. IV. Hunting Out T Dwarfs with Methane Imaging  

NASA Astrophysics Data System (ADS)

We present first results from a major program of methane filter photometry for low-mass stars and brown dwarfs. The definition of a new methane filter photometric system is described. A recipe is provided for the differential calibration of methane imaging data using existing Two Micron All Sky Survey (2MASS) photometry. We show that these filters are effective in discriminating T dwarfs from other types of stars, and we demonstrate this with Anglo-Australian Telescope observations using the IRIS2 imager. Methane imaging data and proper motions are presented for 10 T dwarfs identified as part of the 2MASS Wide-Field T Dwarf Search, seven of them initially identified as T dwarfs using methane imaging. We also present near-infrared moderate-resolution spectra for five T dwarfs newly discovered by this technique. Spectral types obtained from these spectra are compared to those derived from both our methane filter observations and spectral types derived by other observers. Finally, we suggest a range of future programs to which these filters are clearly well suited: the winnowing of T dwarf and Y dwarf candidate objects coming from the next generation of near-infrared sky surveys, the robust detection of candidate planetary-mass brown dwarfs in clusters, the detection of T dwarf companions to known L and T dwarfs via deep methane imaging, and the search for rotationally modulated time-variable surface features on cool brown dwarfs. Based on observations obtained at the Anglo-Australian Telescope, Siding Spring, Australia.

Tinney, C. G.; Burgasser, Adam J.; Kirkpatrick, J. Davy; McElwain, Michael W.

2005-11-01

269

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)

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.

Barnsley, R. M.; Steele, Iain A.; Smith, R. J.; Mawson, Neil R.

2014-07-01

270

Optical endomicroscopy and the road to real-time, in vivo pathology: present and future  

PubMed Central

Epithelial cancers account for substantial mortality and are an important public health concern. With the need for earlier detection and treatment of these malignancies, the ability to accurately detect precancerous lesions has an increasingly important role in controlling cancer incidence and mortality. New optical technologies are capable of identifying early pathology in tissues or organs in which cancer is known to develop through stages of dysplasia, including the esophagus, colon, pancreas, liver, bladder, and cervix. These diagnostic imaging advances, together as a field known as optical endomicroscopy, are based on confocal microscopy, spectroscopy-based imaging, and optical coherence tomography (OCT), and function as “optical biopsies,” enabling tissue pathology to be imaged in situ and in real time without the need to excise and process specimens as in conventional biopsy and histopathology. Optical biopsy techniques can acquire high-resolution, cross-sectional images of tissue structure on the micron scale through the use of endoscopes, catheters, laparoscopes, and needles. Since the inception of these technologies, dramatic technological advances in accuracy, speed, and functionality have been realized. The current paradigm of optical biopsy, or single-area, point-based images, is slowly shifting to more comprehensive microscopy of larger tracts of mucosa. With the development of Fourier-domain OCT, also known as optical frequency domain imaging or, more recently, volumetric laser endomicroscopy, comprehensive surveillance of the entire distal esophagus is now achievable at speeds that were not possible with conventional OCT technologies. Optical diagnostic technologies are emerging as clinically useful tools with the potential to set a new standard for real-time diagnosis. New imaging techniques enable visualization of high-resolution, cross-sectional images and offer the opportunity to guide biopsy, allowing maximal diagnostic yields and appropriate staging without the limitations and risks inherent with current random biopsy protocols. However, the ability of these techniques to achieve widespread adoption in clinical practice depends on future research designed to improve accuracy and allow real-time data transmission and storage, thereby linking pathology to the treating physician. These imaging advances are expected to eventually offer a see-and-treat paradigm, leading to improved patient care and potential cost reduction. Virtual Slides The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/5372548637202968 PMID:22889003

2012-01-01

271

A Very Wide-Field Hybrid (Focusing/Coded Mask) X-Ray Telescope Concept  

NASA Astrophysics Data System (ADS)

The success of Swift at detecting and positioning variable hard X-ray sources, most notably gamma-ray bursts (GRBs), demonstrates that investigations with a very wide field telescope should continue permanently, like the continuing search for supernovas, and its scope expanded. The softer X-ray band is likely to be an even richer arena in which to search for ever more distant GRBs. The X-ray component of their spectra will be enriched by the redshift especially at large distances where the redshift increases very rapidly with distance. Furthermore most GRBs are likely to have an X-ray afterglow, which a very wide field telescope would detect from its birth. Multiple X-ray afterglows can be studied simultaneously. Some GRB models predict that X-ray afterglows will be more numerous than GRBs because they are less narrowly beamed. In addition many other types of variable X-ray sources can be monitored even more effectively than by scanning instruments. There are three possible approaches to a very wide field X-ray telescope, a 2D coded mask like Swift, a 2D lobster-eye telescope, and a hybrid that is a lobster-eye telescope in one dimension and a coded mask in the other. For the same field of view and the same focal length all three could use the same detector system including an omni-directional gamma-ray detector. We offer reasons why the hybrid, which is composed of identical flat mirrors, is the best of the three. It has much less background from diffuse X-rays and known X-ray sources than the 2D coded mask, and has substantially more area and bandwidth than the 2D lobster-eye. While positions are expected to be an arc minute or better, a small number of the mirrors used to fabricate the hybrid can be configured as a KB telescope that when pointed refines positions to arc second precision.

Gorenstein, Paul

2011-09-01

272

WISH, the Wide-field Imaging Surveyor for High-redshifts  

NASA Astrophysics Data System (ADS)

WISH, the Wide-field Imaging Surveyor for High-redshifts, is an infrared Japanese (JAXA/ISAS) space mission concept to conduct very deep and wide-field infrared cosmological surveys at wavelengths from 1-5um to study the properties of galaxies at very high redshift, beyond the epoch of cosmic reionization. Our group at CfA has proposed to the NASA SALMON-2 Mission of Opportunity to provide the characterized focal plane for WISH, building on our experience with Spitzer -IRAC. The WISH mission concept has been developed and studied since 2008, and will be proposed for the upcoming JAXA/ISAS opportunity. WISH has a 1.5m-diameter primary mirror and a wide-field imager covering 850 sq-arcmin, with a pixel scale of 0.155 arcsec for 18um pitch, which fully samples the diffraction-limited image at 1.5um. The telescope is passive cooled and the baseline focal plane uses Teledyne H2RG arrays with a total coverage of about 128 million pixels, although alternatives are being evaluated. The main WISH scientific program is the Ultra Deep Survey (UDS) covering 100 sq-deg down to 28AB mag in at least in five broad infrared bands between about 1-5um. We expect to detect 10^4-5 galaxies at z=8-9, 10^3-4 galaxies at z= 11-12, and 50-100 galaxies at z> 14, many of which are likely to be targets for deep spectroscopy with JWST and extremely large ground-based telescopes. Another main science goal of the mission is the detection of type Ia SNe; our planned, recurrent deep observations will be able to detect them and monitor their light curves in rest-frame infrared wavelengths. During the mission’s 5 year observation lifetime, we expect to detect and monitor >2000 type-Ia SNe up to z ~2. WISH also conducts an Ultra Wide Survey, covering 1000sq-deg down to 24-25AB mag, and an Extreme Survey, covering a limited number of fields of view down to 29-30AB mag. We here report the progress of the WISH project including the basic telescope and satellite design.

Fazio, Giovanni G.; Yamada, T.; Melnick, G. J.; Smith, H. A.; Iwata, I.; Ashby, M. N.; Hora, J. L.; Huang, J.; Wang, Z.; Willner, S. P.; WISH Team

2013-01-01

273

A Powerful New Imager for HST: Performance and Early Science Results from Wide Field Camera 3  

NASA Technical Reports Server (NTRS)

Wide Field Camera 3 (WFC3) was installed into the Hubble Space Telescope during the highly successful Servicing Mission 4 in May, 2009. WFC3 offers sensitive, high resolution imaging over a broad wavelength range from the near UV through the visible to the near IR (200nm - 1700nm). Its capabilities in the near UV and near IR ends of that range represent particularly large advances vs. those of previous HST instruments. In this talk, I will review the purpose and design of the instrument, describe its performance in flight, and highlight some of the initial scientific results from the instrument, including its use in deep infrared surveys in search of galaxies at very high redshift, in investigations of the global processes of star formation in nearby galaxies, and in the study of the recent impact on Jupiter.

Kimble, Randy

2009-01-01

274

Wide field-of-view digital night vision head-mounted display  

NASA Astrophysics Data System (ADS)

SA Photonics has developed (with support from the Air Force Research Lab, the US Army and Vision Systems International) an innovative wide field of view digital night vision head mounted display (HMD). This HMD has an 80 degree field of view to greatly improve operator situational awareness. By using creating an all-digital system, we provide the capability to enhance and record night vision imagery, overlay symbology, and inset video from remote sensors, either mounted on the aircraft or on UAVs. This HMD has been designed with maximum pilot utility in mind, and is easily stowable without impacting center of gravity or maneuverability of the pilot's head within the cockpit. Because the sensors are digital, they can be located right above the pilot's eyes removing any hyperstereoopsis.

Browne, Michael P.

2011-06-01

275

The Wide Field/Planetary Camera 2 (WFPC-2) molecular adsorber  

NASA Technical Reports Server (NTRS)

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.

Barengoltz, Jack; Moore, Sonya; Soules, David; Voecks, Gerald

1995-01-01

276

Investigating the Depth and Data of A Wide Field Survey of the Small Magellanic Cloud  

NASA Astrophysics Data System (ADS)

We investigated the photometric depth of a wide field survey of the Small Magellanic Cloud (SMC) stellar halo. The aim of the survey is to search for evidence of galaxy mergers at the smallest scales. To achieve this it is crucial to understand how the data quality across the survey effects the apparent stellar density profile along different lines of sight. We explored the impact of a variety of factors on the photometric depth of the data including foreground dust extinction and employed two independent methods for determining the photometric completeness. These results will be used to help determine a global stellar density profile of the SMC, as well as show variations with azimuth and to highlight the presence of any deviations.

Paez, Margot; Conn, Blair

2015-01-01

277

Near infrared FRET using wide-field fluorescence lifetime imaging in live animals  

NASA Astrophysics Data System (ADS)

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.

Zhao, Lingling; Abe, Ken; Barroso, Margarida; Intes, Xavier

2013-06-01

278

In-flight Performance of the Detectors on HST/Wide Field Camera 3  

NASA Technical Reports Server (NTRS)

Wide Field Camera 3 (WFC3) is a powerful new imager recently installed on the Hubble Space Telescope during Servicing Mission 4. WFC3 covers wavelengths from the near UV (200nm) to the near infrared (out to 1.7microns), in two channels. The UV/visible (UVIS) channel utilizes two low-noise, UV-enhanced 2Kx4K CCD detectors from e2v, while the IR channel incorporates a 1Kx1K 1.7micron cutoff HgCdTe array, custom-developed for the WFC3 program by Teledyne. We report here on the performance of the detectors in-flight as observed in this summer's Servicing Mission Orbital Verification program.

Kimble, Randy

2009-01-01

279

An in-depth assessment of internal contamination in the Wide Field/Planetary Camera  

NASA Technical Reports Server (NTRS)

Following thermal vacuum/thermal balance testing, a gray haze was discovered on the corners of the Hubble Space Telescope Wide-Field/Planetary Camera aperture window. The phenomenon was suggested to be a result of molecular transport from a low-outgassig structural adhesive. Detailed analysis, both chemical and analytical, were conducted to assess the formation of the haze. Each material was considered individually, as it was not known if the actual contamination was a result of one, many, or possibly none of the materials considered. Results of the analytical assessment and the comparison with the chemical analyses provided incontrovertible evidence as to the cause of the window haze. The resultant cleanup and subsequent elimination of the problem are also addressed.

Maag, Carl; Millard, Jerry; Anderson, Mark

1990-01-01

280

FINDING PERSISTENT SOURCES WITH THE BeppoSAX/WIDE FIELD CAMERA: AN IN-DEPTH ANALYSIS  

SciTech Connect

During the operational life of the Italian/Dutch X-ray satellite (1996-2002), BeppoSAX, its two Wide Field Cameras (WFCs) performed observations that covered the full sky at different epochs. Although the majority of analysis performed on BeppoSAX WFC data concentrated on the detection of transient sources, we have now applied the same techniques developed for the INTEGRAL/IBIS survey to produce the same work with the BeppoSAX WFC data. This work represents the first unbiased source list compilation produced from the overall WFC data set optimized for faint persistent source detection. This approach recovered 182 more sources compared to the previous WFC catalog reported in Verrecchia et al. The catalog contains 404 sources detected between 3 and 17 keV, 10 of which are yet to be seen by the new generation of telescopes.

Capitanio, F.; Fiocchi, M.; Ubertini, P. [INAF IASF-Roma, Via Fosso del Cavaliere 100, 00033 Rome (Italy); Bird, A. J. [School of Physics and Astronomy, University of Southampton, Highfield, Southampton SO17 1BJ (United Kingdom); Scaringi, S. [Department of Astrophysics, Radboud University Nijmegen, P.O. Box 9010, 6500 GL Nijmegen (Netherlands)

2011-07-01

281

VARIABILITY FLAGGING IN THE WIDE-FIELD INFRARED SURVEY EXPLORER PRELIMINARY DATA RELEASE  

SciTech Connect

The Wide-field Infrared Survey Explorer Preliminary Data Release Source Catalog contains over 257 million objects. We describe the method used to flag variable source candidates in the Catalog. Using a method based on the chi-square of single-exposure flux measurements, we generated a variability flag for each object, and have identified almost 460,000 candidate sources that exhibit significant flux variability with greater than {approx}7{sigma} confidence. We discuss the flagging method in detail and describe its benefits and limitations. We also present results from the flagging method, including example light curves of several types of variable sources including Algol-type eclipsing binaries, RR Lyr, W UMa, and a blazar candidate.

Hoffman, D. I.; Cutri, R. M.; Masci, F. J.; Fowler, J. W.; Marsh, K. A.; Jarrett, T. H., E-mail: dhoffman@ipac.caltech.edu [Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States)

2012-05-15

282

A mobile phone-based retinal camera for portable wide field imaging.  

PubMed

Digital fundus imaging is used extensively in the diagnosis, monitoring and management of many retinal diseases. Access to fundus photography is often limited by patient morbidity, high equipment cost and shortage of trained personnel. Advancements in telemedicine methods and the development of portable fundus cameras have increased the accessibility of retinal imaging, but most of these approaches rely on separate computers for viewing and transmission of fundus images. We describe a novel portable handheld smartphone-based retinal camera capable of capturing high-quality, wide field fundus images. The use of the mobile phone platform creates a fully embedded system capable of acquisition, storage and analysis of fundus images that can be directly transmitted from the phone via the wireless telecommunication system for remote evaluation. PMID:24344230

Maamari, Robi N; Keenan, Jeremy D; Fletcher, Daniel A; Margolis, Todd P

2014-04-01

283

WFC3RED: A HST Wide Field Camera 3 Image Processing Pipeline  

NASA Astrophysics Data System (ADS)

WFC3RED is a pipeline for automatically processing imaging data taken with the Wide Field Camera 3 instrument on the Hubble Space Telescope (HST). The pipeline currently supports processing of imaging data from both the IR and UVIS channels and is written in Python and C. The automated processing steps include cosmic-ray removal (UVIS), super-sky subtraction, user defined artifact masking, robust alignment and registration for large mosaics, weight map generation, and drizzling onto a final image mosaic. WFC3RED can combined data across different HST observations, visits and proposals without the need for any pre-defined associations. WFC3RED can create imaging products with a signal-to-noise ratio that matches the most careful step-by-step manual WFC3 reductions.

Magee, D. K.; Bouwens, R. J.; Illingworth, G. D.

2011-07-01

284

Australian SKA Pathfinder: A High-Dynamic Range Wide-Field of View Survey Telescope  

NASA Astrophysics Data System (ADS)

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.

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

285

Background estimation in a wide-field background-limited instrument such as Fermi GBM  

E-print Network

The supporting instrument on board the Fermi Gamma-ray Space Telescope, the Gamma-ray Burst Monitor (GBM) is a wide-field gamma-ray monitor composed of 14 individual scintillation detectors, with a field of view which encompasses the entire unocculted sky. Primarily designed as transient monitors, the conventional method for background determination with GBM-like instruments is to time interpolate intervals before and after the source as a polynomial. This is generally sufficient for sharp impulsive phenomena such as Gamma-Ray Bursts (GRBs) which are characterised by impulsive peaks with sharp rises, often highly structured, and easily distinguishable against instrumental backgrounds. However, smoother long lived emission, such as observed in solar flares and some GRBs, would be difficult to detect in a background-limited instrument using this method. We present here a description of a technique which uses the rates from adjacent days when the satellite has approximately the same geographical footprint to dis...

Fitzpatrick, Gerard; Connaughton, Valerie; Briggs, Michael

2012-01-01

286

Cortical activation following chronic passive implantation of a wide-field suprachoroidal retinal prosthesis  

NASA Astrophysics Data System (ADS)

Objective. The research goal is to develop a wide-field retinal stimulating array for prosthetic vision. This study aimed at evaluating the efficacy of a suprachoroidal electrode array in evoking visual cortex activity after long term implantation. Approach. A planar silicone based electrode array (8 mm × 19 mm) was implanted into the suprachoroidal space in cats (ntotal = 10). It consisted of 20 platinum stimulating electrodes (600 ?m diameter) and a trans-scleral cable terminated in a subcutaneous connector. Three months after implantation (nchronic = 6), or immediately after implantation (nacute = 4), an electrophysiological study was performed. Electrode total impedance was measured from voltage transients using 500 ?s, 1 mA pulses. Electrically evoked potentials (EEPs) and multi-unit activity were recorded from the visual cortex in response to monopolar retinal stimulation. Dynamic range and cortical activation spread were calculated from the multi-unit recordings. Main results. The mean electrode total impedance in vivo following 3 months was 12.5 ± 0.3 k?. EEPs were recorded for 98% of the electrodes. The median evoked potential threshold was 150 nC (charge density 53 ?C cm-2). The lowest stimulation thresholds were found proximal to the area centralis. Mean thresholds from multiunit activity were lower for chronic (181 ± 14 nC) compared to acute (322 ± 20 nC) electrodes (P < 0.001), but there was no difference in dynamic range or cortical activation spread. Significance. Suprachoroidal stimulation threshold was lower in chronic than acute implantation and was within safe charge limits for platinum. Electrode-tissue impedance following chronic implantation was higher, indicating the need for sufficient compliance voltage (e.g. 12.8 V for mean impedance, threshold and dynamic range). The wide-field suprachoroidal array reliably activated the retina after chronic implantation.

Villalobos, Joel; Fallon, James B.; Nayagam, David A. X.; Shivdasani, Mohit N.; Luu, Chi D.; Allen, Penelope J.; Shepherd, Robert K.; Williams, Chris E.

2014-08-01

287

Fire Spectroscopy of Five Late-Type T Dwarfs Discovered with the Wide-Field Infrared Survey Explorer  

E-print Network

We present the discovery of five late-type T dwarfs identified with the Wide-field Infrared Survey Explorer (WISE). Low-resolution near-infrared spectroscopy obtained with the Magellan Folded-port InfraRed Echellette reveal ...

Burgasser, Adam

288

Space Active Optics: toward optimized correcting mirrors for future large spaceborne observatories  

NASA Astrophysics Data System (ADS)

Wave-front correction in optical instruments is often needed, either to compensate Optical Path Differences, off-axis aberrations or mirrors deformations. Active optics techniques are developed to allow efficient corrections with deformable mirrors. In this paper, we will present the conception of particular deformation systems which could be used in space telescopes and instruments in order to improve their performances while allowing relaxing specifications on the global system stability. A first section will be dedicated to the design and performance analysis of an active mirror specifically designed to compensate for aberrations that might appear in future 3m-class space telescopes, due to lightweight primary mirrors, thermal variations or weightless conditions. A second section will be dedicated to a brand new design of active mirror, able to compensate for given combinations of aberrations with a single actuator. If the aberrations to be corrected in an instrument and their evolutions are known in advance, an optimal system geometry can be determined thanks to the elasticity theory and Finite Element Analysis.

Laslandes, Marie; Hugot, Emmanuel; Ferrari, Marc; Lemaitre, Gérard; Liotard, Arnaud

2011-10-01

289

Futurity  

NSDL National Science Digital Library

The Futurity website features "the latest discoveries by scientists at top research universities in the US, UK, Canada and Australia." Currently, some of the participating universities include Boston University, Duke University, McGill University, and the University of Sheffield. Visitors to the homepage will note that there are four areas on the site: Earth & Environment, Health & Medicine, Science & Technology, and Society & Culture. Recently profiled news items include a compelling new discovery from New York University about the reality of a tractor beam that can pull microscopic particles. The Society & Culture section is a real find, as it contains engaging pieces like "Is zero tolerance too hard on students?" and "Big banks loom over finance 'ecosystem'." Also, visitors can browse news items by school or by topic area. Finally, the Week's Most Discussed area is a great way to learn about compelling new stories from around the globe.

290

SixPak -a wide-field IFU for the William Herschel Telescope Lars B. Venema*a  

E-print Network

SixPak - a wide-field IFU for the William Herschel Telescope Lars B. Venema*a , Ton Schoenmakera-based IFU for the 4.2-meter William Herschel Telescope on La Palma. The fibre bundle will consist of 238Pak is an integral wide field fibre unit between the 4.2m William Herschel Telescope (WHT) on La Palma and its

Bershady, Matthew A.

291

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)

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.

Cleveland, Paul E.; Buchko, Matthew T.; Stavely, Richard A.

2003-01-01

292

Photometric redshifts for the CFHTLS T0004 deep and wide fields  

NASA Astrophysics Data System (ADS)

Aims: We compute photometric redshifts in the fourth public release of the Canada-France-Hawaii Telescope Legacy Survey. This unique multi-colour catalogue comprises u^*, g', r', i', z' photometry in four deep fields of 1 deg2 each and 35 deg2 distributed over three wide fields. Methods: We used a template-fitting method to compute photometric redshifts calibrated with a large catalogue of 16 983 high-quality spectroscopic redshifts from the VVDS-F02, VVDS-F22, DEEP2, and the zCOSMOS surveys. The method includes correction of systematic offsets, template adaptation, and the use of priors. We also separated stars from galaxies using both size and colour information. Results: Comparing with galaxy spectroscopic redshifts, we find a photometric redshift dispersion, ?? z/(1+z_s), of 0.028-0.30 and an outlier rate, |? z| ? 0.15× (1+z_s), of 3-4% in the deep field at i'_AB < 24. In the wide fields, we find a dispersion of 0.037-0.039 and an outlier rate of 3-4% at i'_AB < 22.5. Beyond i'_AB = 22.5 in the wide fields the number of outliers rises from 5% to 10% at i'_AB < 23 and i'_AB < 24, respectively. For the wide sample the systematic redshift bias stays below 1% to i'_AB < 22.5, whereas we find no significant bias in the deep fields. We investigated the effect of tile-to-tile photometric variations and demonstrated that the accuracy of our photometric redshifts is reduced by at most 21%. Application of our star-galaxy classifier reduced the contamination by stars in our catalogues from 60% to 8% at i'_AB < 22.5 in our field with the highest stellar density while keeping a complete galaxy sample. Our CFHTLS T0004 photometric redshifts are distributed to the community. Our release includes 592891 (i'_AB < 22.5) and 244701 (i'_AB < 24) reliable galaxy photometric redshifts in the wide and deep fields, respectively. Based on observations obtained with MegaPrime/MegaCam, a joint project of CFHT and CEA/DAPNIA, at the Canada-France-Hawaii Telescope (CFHT) which is operated by the National Research Council (NRC) of Canada, the Institut National des Sciences de l'Univers of the Centre National de la Recherche Scientifique (CNRS) of France, and the University of Hawaii. This work is based in part on data products produced at Terapix and the Canadian Astronomy Data Centre as part of the Canada-France-Hawaii Telescope Legacy Survey, a collaborative project of NRC and CNRS.

Coupon, J.; Ilbert, O.; Kilbinger, M.; McCracken, H. J.; Mellier, Y.; Arnouts, S.; Bertin, E.; Hudelot, P.; Schultheis, M.; Le Fèvre, O.; Le Brun, V.; Guzzo, L.; Bardelli, S.; Zucca, E.; Bolzonella, M.; Garilli, B.; Zamorani, G.; Zanichelli, A.; Tresse, L.; Aussel, H.

2009-06-01

293

MID-INFRARED VARIABILITY FROM THE SPITZER DEEP WIDE-FIELD SURVEY  

SciTech Connect

We use the multi-epoch, mid-infrared Spitzer Deep Wide-Field Survey to investigate the variability of objects in 8.1 deg{sup 2} of the NOAO Deep Wide Field Survey Booetes 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 {mu}m 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 ({sigma}{sub 12}) exceeds that for all sources with the same magnitude by 2{sigma}. We then examine the mid-IR colors of the variable sources and match them with X-ray sources from the XBooetes survey, radio catalogs, 24 {mu}m 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 {mu}m 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 {gamma} {approx} 0.5 at both 3.6 and 4.5 {mu}m, and an amplitude of S {sub 0} {approx_equal} 0.1 mag on rest-frame timescales of 2 yr. The variability amplitude is higher for shorter rest-frame wavelengths and lower luminosities.

Kozlowski, Szymon; Kochanek, Christopher S.; Assef, Roberto J. [Department of Astronomy, The Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Stern, Daniel; Eisenhardt, P. R.; Gorjian, V.; Griffith, R. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Drive, Pasadena, CA 91109 (United States); Ashby, Matthew L. N.; Brodwin, M. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Bock, J. J.; Borys, C. [California Institute of Technology, Pasadena, CA 91125 (United States); Brand, K.; Grogin, N. [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Brown, M. J. I. [School of Physics, Monash University, Clayton 3800, Victoria (Australia); Cool, R. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Cooray, A. [University of California, Irvine, CA 92697 (United States); Croft, S. [University of California, Berkeley, CA 94720 (United States); Dey, Arjun [National Optical Astronomical Observatory, 950 North Cherry Avenue, Tucson, AZ 85719 (United States); Gonzalez, A. [Department of Astronomy, University of Florida, Gainesville, FL 32611 (United States); Ivison, R., E-mail: simkoz@astronomy.ohio-state.ed [UK Astronomy Technology Centre, Royal Observatory, Blackford Hill, Edinburgh, EH9 3HJ (United Kingdom)

2010-06-10

294

A generalized measurement equation and van Cittert-Zernike theorem for wide-field radio astronomical interferometry  

NASA Astrophysics Data System (ADS)

We derive a generalized van Cittert-Zernike (vC-Z) theorem for radio astronomy that is valid for partially polarized sources over an arbitrarily wide field of view (FoV). The classical vC-Z theorem is the theoretical foundation of radio astronomical interferometry, and its application is the basis of interferometric imaging. Existing generalized vC-Z theorems in radio astronomy assume, however, either paraxiality (narrow FoV) or scalar (unpolarized) sources. Our theorem uses neither of these assumptions, which are seldom fulfiled in practice in radio astronomy, and treats the full electromagnetic field. To handle wide, partially polarized fields, we extend the two-dimensional (2D) electric field (Jones vector) formalism of the standard `Measurement Equation' (ME) of radio astronomical interferometry to the full three-dimensional (3D) formalism developed in optical coherence theory. The resulting vC-Z theorem enables full-sky imaging in a single telescope pointing, and imaging based not only on standard dual-polarized interferometers (that measure 2D electric fields) but also electric tripoles and electromagnetic vector-sensor interferometers. We show that the standard 2D ME is easily obtained from our formalism in the case of dual-polarized antenna element interferometers. We also exploit an extended 2D ME to determine that dual-polarized interferometers can have polarimetric aberrations at the edges of a wide FoV. Our vC-Z theorem is particularly relevant to proposed, and recently developed, wide FoV interferometers such as Low Frequency Array (LOFAR) and Square Kilometer Array (SKA), for which direction-dependent effects will be important.

Carozzi, T. D.; Woan, G.

2009-05-01

295

A deep, wide-field study of Holmberg II with Suprime-Cam: evidence for ram pressure stripping  

NASA Astrophysics Data System (ADS)

We present a deep, wide-field optical study of the M81 group dwarf galaxy Holmberg II (HoII) based on Subaru/Suprime-Cam imaging. Individual stars are resolved down to I ˜ 25.2, that is, about 1.5 mag below the tip of the red giant branch (RGB). We use resolved star counts in the outskirts of the galaxy to measure the radial surface brightness profile down to ?V ˜ 32 mag arcsec-2, from which we determine a projected exponential scalelength of 0.70 ± 0.01 arcmin (i.e. 0.69 ± 0.01 kpc). The composite profile, ranging from the cored centre out to R = 7 arcmin, is best fitted by an Elson-Fall-Freeman profile which gives a half-light radius of 1.41 ± 0.04 arcmin (i.e. 1.39 ± 0.04 kpc), and an absolute magnitude MV = -16.3. The low surface brightness stellar component of HoII is regular and symmetric and has an extent much smaller than the vast H I cloud in which it is embedded. We compare the spatial distribution of the young, intermediate-age and old stellar populations, and find that the old RGB stars are significantly more centrally concentrated than the young stellar populations, contrary to what is observed in most dwarf galaxies of the local Universe. We discuss these properties in the context of the comet-like distribution of H I gas around HoII, and argue for the presence of a hot intragroup medium in the vicinity of HoII to explain the contrasting morphologies of gas and stars. Based on data collected at the Subaru Telescope, which is operated by the National Astronomical Observatory of Japan.

Bernard, Edouard J.; Ferguson, Annette M. N.; Barker, Michael K.; Irwin, Michael J.; Jablonka, Pascale; Arimoto, Nobuo

2012-11-01

296

A generalised Measurement Equation and van Cittert-Zernike theorem for wide-field radio astronomical interferometry  

E-print Network

We derive a generalised van Cittert-Zernike (vC-Z) theorem for radio astronomy that is valid for partially polarized sources over an arbitrarily wide field-of-view (FoV). The classical vC-Z theorem is the theoretical foundation of radio astronomical interferometry, and its application is the basis of interferometric imaging. Existing generalised vC-Z theorems in radio astronomy assume, however, either paraxiality (narrow FoV) or scalar (unpolarized) sources. Our theorem uses neither of these assumptions, which are seldom fulfilled in practice in radio astronomy, and treats the full electromagnetic field. To handle wide, partially polarized fields, we extend the two-dimensional electric field (Jones vector) formalism of the standard "Measurement Equation" of radio astronomical interferometry to the full three-dimensional formalism developed in optical coherence theory. The resulting vC-Z theorem enables all-sky imaging in a single telescope pointing, and imaging using not only standard dual-polarized interferometers (that measure 2-D electric fields), but also electric tripoles and electromagnetic vector-sensor interferometers. We show that the standard 2-D Measurement Equation is easily obtained from our formalism in the case of dual-polarized antenna element interferometers. We find, however, that such dual-polarized interferometers can have polarimetric aberrations at the edges of the FoV that are often correctable. Our theorem is particularly relevant to proposed and recently developed wide FoV interferometers such as LOFAR and SKA, for which direction-dependent effects will be important.

T. D. Carozzi; G. Woan

2008-11-30

297

Calibration of a wide-field frequency-domain fluorescence lifetime microscopy system using light emitting diodes as light sources.  

PubMed

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. PMID:17204064

Elder, A D; Frank, J H; Swartling, J; Dai, X; Kaminski, C F

2006-11-01

298

Recent Advances and Future Visions: Temporal Variability of Optical and Bio-optical Properties of the Ocean  

Microsoft Academic Search

Introduction Ocean optics concerns studies of light and its prop- agation through the ocean, and bio-optics connotes biological effects on optical properties and vice versa. These two terms are so intertwined that they are often used interchangeably. Knowledge of the variability of optical and bio-optical properties of the ocean is important for many scientific and practical problems (e.g., Dickey and

Tommy D. Dickey; Grace C. Chang

2001-01-01

299

Performance Comparisons Between Carbon Nanotubes, Optical, and Cu for Future High-Performance On-Chip Interconnect Applications  

Microsoft Academic Search

Optical interconnects and carbon nanotubes (CNTs) present promising options for replacing the existing Cu-based global\\/semiglobal (optics and CNT) and local (CNT) wires. We quantify the performance of these novel interconnects and compare it with Cu\\/low-kappa wires for future high-performance integrated circuits. We find that for a local wire, a CNT bundle exhibits a smaller latency than Cu for a given

Kyung-Hoae Koo; Hoyeol Cho; Pawan Kapur; Krishna C. Saraswat

2007-01-01

300

Wide-Field Infrared Survey Explorer Observations of the Evolution of Massive Star-Forming Regions  

NASA Technical Reports Server (NTRS)

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.

Koenig, X. P.; Leisawitz, D. T.; Benford, D. J.; Rebull, L. M.; Padgett, D. L.; Assef, R. J.

2011-01-01

301

Wide-Field Infrared Survey Explorer Observations of the Evolution of Massive Star-Forming Regions  

NASA Technical Reports Server (NTRS)

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.

Koenig, X. P.; Leisawitz, D. T.; Benford, D. J.; Rebull, L. M.; Padgett, D. L.; Asslef, R. J.

2012-01-01

302

Pulsed light imaging for wide-field dosimetry of photodynamic therapy in the skin  

NASA Astrophysics Data System (ADS)

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.

Davis, Scott C.; Sexton, Kristian; Chapman, Michael Shane; Maytin, Edward; Hasan, Tayyaba; Pogue, Brian W.

2014-03-01

303

Exoplanets from the Arctic: The First Wide-field Survey at 80°N  

NASA Astrophysics Data System (ADS)

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.

Law, Nicholas M.; Carlberg, Raymond; Salbi, Pegah; Ngan, Wai-Hin Wayne; Ahmadi, Aida; Steinbring, Eric; Murowinski, Richard; Sivanandam, Suresh; Kerzendorf, Wolfgang

2013-03-01

304

The Wide Field Imager for the Athena X-ray Observatory  

NASA Astrophysics Data System (ADS)

The Wide Field Imager (WFI) is one of the two scientific instruments of the Athena mission concept proposed for ESA's next large X-ray Observatory. The instrument will make optimal use of the grasp provided by the Athena mirror system, by combining a sensitive 40' diameter field of view DEPFET detector with an excellent spectral resolution and a pixel size properly sampling the angular resolution of 5" on-axis (half energy width). This synthesis makes the WFI a very powerful survey instrument, exceeding existing facilities by up to a factor of 100 in survey power. This will allow, e.g., to observe the earliest low-luminosity AGNs in the Universe, unraveling the seeds and growth mechanism of AGN at high-redshift. In addition, the WFI will provide unprecedented high-time resolution and high count rate capabilities for the observation of bright sources with low pile-up and high efficiency. I will present the instrument concept, the status of the hardware development, and highlight the breakthrough scientific capabilities of the instrument.

Rau, A.

2014-07-01

305

The Wide Field Imager for the Athena X-ray Observatory  

NASA Astrophysics Data System (ADS)

The Wide Field Imager (WFI) is one of the two scientific instruments of the Athena mission concept proposed for ESA's next large X-ray Observatory. The instrument will make optimal use of the grasp provided by the Athena mirror system, by combining a sensitive 40' diameter field of view DEPFET detector with an excellent spectral resolution and a pixel size properly sampling the angular resolution of 5" on-axis (half energy width). This synthesis makes the WFI a very powerful survey instrument, exceeding existing facilities by up to a factor of 100 in survey power. This will allow, e.g., to observe the earliest low-luminosity AGNs in the Universe, unraveling the seeds and growth mechanism of AGN at high-redshift. In addition, the WFI will provide unprecedented high-time resolution and high count rate capabilities for the observation of bright sources with low pile-up and high efficiency. I will present the instrument concept, the status of the hardware development, and highlight the breakthrough scientific capabilities of the instrument.

Rau, Arne

306

A new era of wide-field submillimetre imaging: on-sky performance of SCUBA-2  

NASA Astrophysics Data System (ADS)

SCUBA-2 is the largest submillimetre wide-field bolometric camera ever built. This 43 square arc- minute field-of-view instrument operates at two wavelengths (850 and 450 microns) and has been installed on the James Clerk Maxwell Telescope on Mauna Kea, Hawaii. SCUBA-2 has been successfully commissioned and operational for general science since October 2011. This paper presents an overview of the on-sky performance of the instrument during and since commissioning in mid- 2011. The on-sky noise characteristics and NEPs of the 450 ?m and 850 ?m arrays, with average yields of approximately 3400 bolometers at each wavelength, will be shown. The observing modes of the instrument and the on-sky calibration techniques are described. The culmination of these efforts has resulted in a scientifically powerful mapping camera with sensitivities that allow a square degree of sky to be mapped to 10 mJy/beam rms at 850 ?m in 2 hours and 60 mJy/beam rms at 450 ?m in 5 hours in the best weather.

Dempsey, Jessica T.; Holland, Wayne S.; Chrysostomou, Antonio; Berry, David S.; Bintley, Daniel; Chapin, Edward L.; Craig, Simon C.; Coulson, Iain M.; Davis, Gary R.; Friberg, Per; Jenness, Tim; Gibb, Andy G.; Parsons, Harriet A. L.; Scott, Douglas; Thomas, Holly S.; Tilanus, Remo P. J.; Robson, Ian; Walther, Craig A.

2012-09-01

307

THE WIDE-FIELD INFRARED SURVEY EXPLORER (WISE): MISSION DESCRIPTION AND INITIAL ON-ORBIT PERFORMANCE  

SciTech Connect

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 Two 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 (WISE) is mapping the whole sky following its launch on 2009 December 14. WISE began surveying the sky on 2010 January 14 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 2010 November). 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 {mu}m. 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 {mu}m, and the astrometric precision for high signal-to-noise sources is better than 0.''15.

Wright, Edward L.; McLean, Ian [UCLA Astronomy, P.O. Box 951547, Los Angeles, CA 90095-1547 (United States); Eisenhardt, Peter R. M.; Mainzer, Amy K.; Ressler, Michael E.; Gautier, Thomas N. [Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Cutri, Roc M.; Jarrett, Thomas; Kirkpatrick, J. Davy; Padgett, Deborah [Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States); McMillan, Robert S. [University of Arizona, 1629 East University Boulevard, Tucson, AZ 85721 (United States); Skrutskie, Michael [Department of Astronomy, University of Virginia, Charlottesville, VA 22903 (United States); Stanford, S. A. [Physics Department, University of California, Davis, CA 95616 (United States); Cohen, Martin; Walker, Russell G. [Monterey Institute for Research in Astronomy, 200 8th Street, Marina, CA 93933 (United States); Mather, John C.; Leisawitz, David; Benford, Dominic [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Lonsdale, Carol J. [National Radio Astronomy Observatory, Charlottesville, VA 22903 (United States); Blain, Andrew, E-mail: wright@astro.ucla.ed [California Institute of Technology, Pasadena, CA 91125 (United States)

2010-12-15

308

Luminous 3 Lyman Break Galaxies in Deep and Wide Field Surveys  

NASA Astrophysics Data System (ADS)

We present a survey of bright 3 LBGs in the the NOAO Bootes fields and SDSS deep stripe field. Our new LBT U-band survey, combined with the existing NOAO Bootes field survey, allows us to build up a sample of 15,000 photometrically-selected LBGs at 3 in the 9 square degree survey area. With the large survey area, we study UV luminosity function, stellar mass function and clustering in bright 3 LBGs. We compare our results with the results measured in other high-z LBG samples to test the cold flow accretion model and put strong constraint on the cosmic star formation efficiency and star formation history in these galaxies. Furthermore, the new Bootes wide field survey and our newly coadded imaging data in SDSS deep stripe field provide a survey area two orders of magnitude larger than any of previous deep field survey, which allow us to reveal a population of the most luminous LBGs at 3. With L> 7L* and star formation rate (SFR) ~500 M/yr, these spectroscopically-confirmed LBGs are some of the rarest and most intensive star forming systems in the early Universe. The fellow-up deep spectroscopic observations and approved Spitzer and HST observations will reveal the physical properties, place these newly discovered galaxies in the context of galaxy growth through merger and cold flow accretion at the peak era of cosmic star formation,and provide a unique laboratory for galaxy formation theory.

Bian, Fuyan; Fan, X.; Jiang, L.; McGreer, I. D.; Dey, A.; Green, R. F.; Walter, F.; Maiolino, R.; Lee, K.; Dave, R.

2013-01-01

309

Recalibrating the Wide-field Infrared Survey Explorer (WISE) W4 Filter  

NASA Astrophysics Data System (ADS)

We present a revised effective wavelength and photometric calibration for the Wide-field Infrared Survey Explorer W4 band, including tests of empirically motivated modifications to its pre-launch laboratory-measured relative system response curve. We derived these by comparing measured W4 photometry with photometry synthesised from spectra of galaxies and planetary nebulae. The difference between measured and synthesised photometry using the pre-launch laboratory-measured W4 relative system response can be as large as 0.3 mag for galaxies and 1 mag for planetary nebulae. We find the W4 effective wavelength should be revised upward by 3.3%, from 22.1 to 22.8 ?m, and the W4 AB magnitude of Vega should be revised from m W4 = 6.59 to m W4 = 6.66. In an attempt to reproduce the observed W4 photometry, we tested three modifications to the pre-launch laboratory-measured W4 relative system response curve, all of which have an effective wavelength of 22.8 ?m. Of the three relative system response curve models tested, a model that matches the laboratory-measured relative system response curve, but has the wavelengths increased by 3.3% (or ~= 0.73 ?m) achieves reasonable agreement between the measured and synthesised photometry.

Brown, M. J. I.; Jarrett, T. H.; Cluver, M. E.

2014-12-01

310

THE FIRST ULTRA-COOL BROWN DWARF DISCOVERED BY THE WIDE-FIELD INFRARED SURVEY EXPLORER  

SciTech Connect

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.

Mainzer, A.; Cushing, Michael C.; Eisenhardt, P. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Skrutskie, M.; Beaton, R. [University of Virginia, 530 McCormick Road Charlottesville, VA 22904 (United States); Gelino, C. R.; Kirkpatrick, J. Davy; Jarrett, T.; Masci, F.; Marsh, K.; Padgett, D. [Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States); Marley, Mark S. [NASA Ames Research Center, Mountain View, CA 94043 (United States); Saumon, D. [Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, NM 87545 (United States); Wright, E.; McLean, I. [UCLA Astronomy, P.O. Box 91547, Los Angeles, CA 90095-1547 (United States); Dietrich, M. [Department of Astronomy, Ohio State University, 140 W 18th Avenue, Columbus, OH 43210-1173 (United States); Garnavich, P.; Rueff, K. [University of Notre Dame, 225 Nieuwland Science Hall, Notre Dame, IN 46556-5670 (United States); Kuhn, O. [Large Binocular Telescope Observatory, University of Arizona, 933 N. Cherry Ave., Tucson, AZ 85721 (United States); Leisawitz, D., E-mail: amainzer@jpl.nasa.gov [Goddard Space Flight Center, 8800 Greenbelt Rd., Greenbelt, MD 20771 (United States)

2011-01-01

311

WIDE-FIELD INFRARED SURVEY EXPLORER OBSERVATIONS OF THE EVOLUTION OF MASSIVE STAR-FORMING REGIONS  

SciTech Connect

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.

Koenig, X. P.; Leisawitz, D. T.; Benford, D. J.; Padgett, D. L. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Rebull, L. M. [Spitzer Science Center (SSC), California Institute of Technology, M/S 220-6, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Assef, R. J. [Jet Propulsion Laboratory, MS 169-530, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States)

2012-01-10

312

The Wide-Field Infrared Survey Explorer (WISE): Mission Description and Initial On-Orbit Performance  

NASA Technical Reports Server (NTRS)

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".

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

313

Wide Field Collimator 2 (WFC2) for GOES Imager and Sounder  

NASA Technical Reports Server (NTRS)

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

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

314

An Automatic Technique for Finding Faint Moving Objects in Wide Field CCD Images  

NASA Astrophysics Data System (ADS)

The traditional method used to find moving objects in astronomical images is to blink pairs or series of frames after registering them to align the background objects. While this technique is extremely efficient in terms of the low signal-to-noise ratio that the human sight can detect, it proved to be extremely time-, brain- and eyesight-consuming. The wide-field images provided by the large CCD mosaic recently built at IfA cover a field of view of 20 to 30' over 8192(2) pixels. Blinking such images is an enormous task, comparable to that of blinking large photographic plates. However, as the data are available digitally (each image occupying 260Mb of disk space), we are developing a set of computer codes to perform the moving object identification in sets of frames. This poster will describe the techniques we use in order to reach a detection efficiency as good as that of a human blinker; the main steps are to find all the objects in each frame (for which we rely on ``S-Extractor'' (Bertin & Arnouts (1996), A&ASS 117, 393), then identify all the background objects, and finally to search the non-background objects for sources moving in a coherent fashion. We will also describe the results of this method applied to actual data from the 8k CCD mosaic. {This work is being supported, in part, by NSF grant AST 92-21318.}

Hainaut, O. R.; Meech, K. J.

1996-09-01

315

Wide-field computational color imaging using pixel super-resolved on-chip microscopy  

PubMed Central

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

Greenbaum, Alon; Feizi, Alborz; Akbari, Najva; Ozcan, Aydogan

2013-01-01

316

WIDE-FIELD WIDE-BAND INTERFEROMETRIC IMAGING: THE WB A-PROJECTION AND HYBRID ALGORITHMS  

SciTech Connect

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.

Bhatnagar, S.; Rau, U.; Golap, K., E-mail: sbhatnag@nrao.edu, E-mail: rurvashi@nrao.edu, E-mail: kgolap@nrao.edu [National Radio Astronomy Observatory, Socorro, NM 87801 (United States)

2013-06-20

317

Nearby M, L, and T Dwarfs Discovered by the Wide-field Infrared Survey Explorer (WISE)  

E-print Network

In our effort to complete the census of low-mass stars and brown dwarfs in the immediate Solar Neighborhood, we present spectra, photometry, proper motions, and distance estimates for forty-two low-mass star and brown dwarf candidates discovered by the Wide-field Infrared Survey Explorer (WISE). We also present additional follow-up information on twelve candidates selected using WISE data but previously published elsewhere. The new discoveries include fifteen M dwarfs, seventeen L dwarfs, five T dwarfs, and five objects of other type. Among these discoveries is a newly identified "unusually red L dwarf" (WISE J223527.07+451140.9), four peculiar L dwarfs whose spectra are most readily explained as unresolved L+T binary systems, and a T9 dwarf (WISE J124309.61+844547.8). We also show that the recently discovered red L dwarf WISEP J004701.06+680352.1 (Gizis et al. 2012) may be a low-gravity object and hence young and potentially low mass (< 25 MJup).

Thompson, Maggie A; Mace, Gregory N; Cushing, Michael C; Gelino, Christopher R; Griffith, Roger L; Skrutskie, Michael F; Eisenhardt, Peter R M; Wright, Edward L; Marsh, Kenneth A; Mix, Katholeen J; Beichman, Charles A; Faherty, Jacqueline K; Toloza, Odette; Ferrara, Jocelyn; Apodaca, Brian; McLean, Ian S; Bloom, Joshua S

2013-01-01

318

Wide Field Camera 3 Instrument Handbook for Cycle 21 v. 5.0  

NASA Astrophysics Data System (ADS)

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.

Dressel, L.

2012-12-01

319

Blood vessel segmentation and width estimation in ultra-wide field scanning laser ophthalmoscopy  

PubMed Central

Features of the retinal vasculature, such as vessel widths, are considered biomarkers for systemic disease. The aim of this work is to present a supervised approach to vessel segmentation in ultra-wide field of view scanning laser ophthalmoscope (UWFoV SLO) images and to evaluate its performance in terms of segmentation and vessel width estimation accuracy. The results of the proposed method are compared with ground truth measurements from human observers and with existing state-of-the-art techniques developed for fundus camera images that we optimized for UWFoV SLO images. Our algorithm is based on multi-scale matched filters, a neural network classifier and hysteresis thresholding. After spline-based refinement of the detected vessel contours, the vessel widths are estimated from the binary maps. Such analysis is performed on SLO images for the first time. The proposed method achieves the best results, both in vessel segmentation and in width estimation, in comparison to other automatic techniques. PMID:25574441

Pellegrini, Enrico; Robertson, Gavin; Trucco, Emanuele; MacGillivray, Tom J.; Lupascu, Carmen; van Hemert, Jano; Williams, Michelle C.; Newby, David E.; van Beek, Edwin JR; Houston, Graeme

2014-01-01

320

SuperBIT: Wide-field, Sub-arcsecond Imaging from the Super Pressure Balloon Platform  

NASA Astrophysics Data System (ADS)

The scientific potential of near-diffraction-limited imaging from mid-latitude ultra-long duration balloon payloads is well known. 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. Collaborators at the University of Toronto have recently integrated a half-meter class telescope with a prototype subarcsecond pointing system. SuperBIT will adapt the existing system to the requirements of the mid-latitude super-pressure balloon (SPB) payload, and demonstrate its imaging capability during an ultra-long duration balloon flight that will take off from Wanaka, New Zealand, in the 2016-17 Austral summer. The demonstration instrument will provide imaging with a half-degree field of view and 0.3-arcsecond resolution in five bands between 300 and1000 nm, with sensitivities in the shape-band exceeding 24th magnitude(>5 sigma) in 300 seconds of integration. Our observing schedule will be 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 wide range of cluster masses and morphologies. Aside from demonstrating the technical approach, these data will enable a systematic program to constrain the mass-observable relations over an unprecedented scale. A successful demonstration of the technical approach and the scientific potential will motivate future development of facility-class instruments on the SPB platform.

Rhodes, Jason; Fraisse, Aurélien A.; Jones, William C.; Netterfield, Calvin Barth; Massey, Richard

2014-06-01

321

National Aeronautics and Space Administration Wide-fieldInfraredSurveyExplorer  

E-print Network

-synchronous orbit. 7-month baseline mission including a 1-month checkout. Sky-pointing instrument. 11-second data of the sky. It includes: A 40-cm telescope and reimaging optics. A scan mirror to stabilize the line Telescope, Optics, Scan Mirror Ball Aerospace Spacecraft, System Testing, Operations Support IPAC

322

Experience Using the Heidelberg Retina Angiograph 2 with a Wide-Field Contact Lens System in Diabetic Retinopathy Cases  

PubMed Central

Introduction: HRA (Heiderberg Retina Angiograph) 2 uses a confocal scanning laser system which can provide high quality digital images but its imaging field is only 30°at most. HRA2 with a wide-field contact lens system allows an imaging field of up to 150°. Methods: We examined the advantages and disadvantages of HRA2, with a wide-field contact lens, for the evaluating diabetic retinopathy (DR). Results: HRA2 was beneficial for obtaining images of the entire retina simultaneously, without missing peripheral retinal non-perfusion and neovascularization. On the other hand, clear images connot be acquired in cases with media opacities such as corneal dystrophy, cataract and asteroid hyalosis, or in those with yellow tinted IOL. Conclusions: HRA2 with a wide-field contact lens is useful for visualizing peripheral retinal lesions in DR cases. PMID:24082980

Shiibashi, Miyo; Yoshimoto, Miwako; Shigeeda, Takashi; Kitano, Shigehiko; Kato, Satoshi

2013-01-01

323

Wide-field kinematic structure of early-type galaxy halos  

NASA Astrophysics Data System (ADS)

The stellar halos of nearby galaxies bare the signatures of the mass-assembly processes that have driven galaxy evolution over the last ˜10 Gyr. Finding and interpreting these relict clues in galaxies within and beyond the local group offers one of the most promising avenues for understanding how galaxies accumulate their stars over time. To tackle this problem we have performed a systematic study of the wide-field kinematic structure of nearby (D< 30 Mpc) early-type galaxies (ETGs), based on two-dimensional absorption-line stellar spectroscopy out to several effective radii (˜3 R e). The 22 galaxies presented here span a range of environments (field, group, and cluster), intrinsic luminosities (-22.4 < Mk < -25.6), and morphologies (S0-E0). The data consist of moderate resolution integrated-stellar-light spectra extracted from the individual slitlets of custom Keck/DEIMOS slitmasks. The complicating effects of strong emission line features are avoided by targeting the spectral region surrounding the near-infrared Calcium II triplet. For each spectrum, we parameterize the line-of-sight velocity distribution (LOSVD) as a truncated Gauss-Hermite series convolved with an optimally weighted combination of stellar templates. These kinematic measurements (V, sigma, h3, and h4) are combined with literature values to construct spatially resolved maps of large-scale kinematic structure. A variety of kinematic behaviors are observed beyond ~1 Re, potentially reflecting the stochastic and chaotic assembly of stellar bulges and halos in early-type galaxies. Next, we describe a global analysis (out to 5 Re) of kinematics and metallicity in the nearest S0 galaxy, NGC 3115, along with implications for its assembly history. The data include high-quality wide-field imaging and multi-slit spectra of the field stars and globular clusters (GCs). Within two effective radii, the bulge (as traced by the stars and metal-rich GCs) is flattened and rotates rapidly. At larger radii, the rotation declines dramatically, while the characteristic GC metallicities also decrease with radius. We argue that this pattern is not naturally explained by a binary major merger, but instead by a two-phase assembly process where the inner regions have formed in an early violent, dissipative phase, followed by the protracted growth of the outer parts via minor mergers. To test this hypothesis and improve our understanding of the growth of stellar halos we compare our observational results to high-resolution cosmological galaxy simulations. We describe a methodology for visualizing these data and present our initial comparisons between theory and observation, which suggest that the aggregate effects of many minor mergers dictate the large-scale kinematic structure of present day ETGs.

Arnold, Jacob Antony

324

Real-time control for the high order, wide field DRAGON AO test bench  

NASA Astrophysics Data System (ADS)

DRAGON is a high order, wide field AO test-bench at Durham. A key feature of DRAGON is the ability to be operated at real-time rates, i.e. frame rates of up to 1kHz, with low latency to maintain AO performance. Here, we will present the real-time control architecture for DRAGON, which includes two deformable mirrors, eight wavefront sensors and thousands of Shack-Hartmann sub-apertures. A novel approach has been taken to allow access to the wavefront sensor pixel stream, reducing latency and peak computational load, and this technique can be implemented for other similar wavefront sensor cameras with no hardware costs. We report on experience with an ELT-suitable wavefront sensor camera. DRAGON will form the basis for investigations into hardware acceleration architectures for AO real-time control, and recent work on GPU and many-core systems (including the Xeon Phi) will be reported. Additionally, the modular structure of DRAGON, its remote control capabilities, distribution of AO telemetry data, and the software concepts and architecture will be reported. Techniques used in DRAGON for pixel processing, slope calculation and wavefront reconstruction will be presented. This will include methods to handle changes in CN2 profile and sodium layer profile, both of which can be modelled in DRAGON. DRAGON software simulation techniques linking hardware-in-the-loop computer models to the DRAGON real-time system and control software will also be discussed. This tool allows testing of the DRAGON system without requiring physical hardware and serves as a test-bed for ELT integration and verification techniques.

Basden, Alastair; Bharmal, Nazim A.; Bitenc, Urban; Dipper, Nigel; Morris, Tim; Myers, Richard; Reeves, Andrew; Younger, Eddy

2014-07-01

325

Ocular findings in patients with alopecia areata: role of ultra-wide-field retinal imaging.  

PubMed

Alopecia areata is understood as an autoimmune disease T cell-mediated mainly involving hair follicles in humans. It is a multifactorial aetiologic disease characterised by non-scarring alopecia and asymptomatic areas, affecting approximately 2 % of dermatology patients. Recent studies suggest that the pathogenesis of AA plays an important role in the association of certain HLA groups, neuroendocrine parameters and immunogenic factors. During 3 months (March to May 2013) at Hospital Clínic de Barcelona, 22 patients with severe alopecia areata underwent ophthalmic examination to determine whether there were ocular findings in the following parameters: Best-corrected visual acuity on decimal Snellen optotype, anterior segment slit-lamp examination and photograph, intraocular pressure measurement and dilated fundoscopy. Ultra-wide-field retinal imaging with or without red-free photograph was carried out with the Optomap 200 Tx (Optos, DunFermline, UK). Forty-four eyes of 22 patients were analysed [15 females (68.2 %)]. The mean age was 38.9 (SD 13.7) and mean time of evolution was 19.9 years (SD 16.3). Alopecia areata clinical patterns were multifocal [n = 10 (45.5 %)], universalis [n = 7 (31.8 %)], totalis [n = 3 (13.6 %)] and focal [n = 2 (9.1 %)]. Best-corrected visual acuity was 1.0 in almost all patients, but only three eyes (6.8 %) had vision of 0.7. Ocular findings were as follows: madarosis [n = 7 partial loss of eyelashes (31.85 %) and n = 4 total loss (18.2 %)], lens changes [n = 4 (18.2 %)], cataract [n = 3 (13.65 %)]. Ultra-wide fundus photography examination showed peripheral drusen [n = 17 eyes (38.6 %)], white-without-pressure changes [n = 8 eyes (18.22 %)] and peripheral retinal degenerations [n = 3 eyes (6.81 %)]. Ocular findings in patients with alopecia areata are reported and discussed by dermatologic and ophthalmic evaluation. PMID:25450413

de Andrade, Francisco Assis; Giavedoni, Priscila; Keller, Johannes; Sainz-de-la-Maza, Maria Tereza; Ferrando, Juan

2014-12-01

326

Red Galaxy Clustering in the NOAO Deep Wide-Field Survey  

NASA Astrophysics Data System (ADS)

We have measured the clustering of 0.30Wide-Field Survey (NDWFS). The area and BWRI passbands of the NDWFS allow samples of >~103 galaxies to be selected as a function of spectral type, absolute magnitude, and photometric redshift. Spectral synthesis models can be used to predict the colors and luminosities of a galaxy population as a function of redshift. We have used PEGASE2 models, with exponentially declining star formation rates, to estimate the observed colors and luminosity evolution of galaxies and to connect, as an evolutionary sequence, related populations of galaxies at different redshifts. A red galaxy sample, with present-day rest-frame Vega colors of BW-R>1.44, was chosen to allow comparisons with the 2dF Galaxy Redshift Survey and Sloan Digital Sky Survey. We find the spatial clustering of red galaxies to be a strong function of luminosity, with r0 increasing from 4.4+/-0.4 h-1 Mpc at MR-5logh~-20.0 to 11.2+/-1.0 h-1 Mpc at MR-5logh~-22.0. Clustering evolution measurements using samples where the rest-frame selection criteria vary with redshift, including all deep single-band magnitude limited samples, are biased because of the correlation of clustering with rest-frame color and luminosity. The clustering of -21.51.44 galaxies exhibits no significant evolution over the redshift range observed with r0=6.3+/-0.5 h-1 Mpc in comoving coordinates. This is consistent with recent ?CDM models in which the bias of L* galaxies undergoes rapid evolution and r0 evolves very slowly at z<2.

Brown, Michael J. I.; Dey, Arjun; Jannuzi, Buell T.; Lauer, Tod R.; Tiede, Glenn P.; Mikles, Valerie J.

2003-11-01

327

Tracker controls development and control architecture for the Hobby-Eberly Telescope Wide Field Upgrade  

NASA Astrophysics Data System (ADS)

To enable the Hobby-Eberly Telescope Wide Field Upgrade, the University of Texas Center for Electromechanics and McDonald Observatory are developing a precision tracker system - a 15,000 kg robot to position a 3,100 kg payload within 10 microns of a desired dynamic track. Performance requirements to meet science needs and safety requirements that emerged from detailed Failure Modes and Effects Analysis resulted in a system of 14 precision controlled actuators and 100 additional analog and digital devices (primarily sensors and safety limit switches). This level of system complexity and emphasis on fail-safe operation is typical of large modern telescopes and numerous industrial applications. Due to this complexity, demanding accuracy requirements, and stringent safety requirements, a highly versatile and easily configurable centralized control system that easily links with modeling and simulation tools during the hardware and software design process was deemed essential. The Matlab/Simulink simulation environment, coupled with dSPACE controller hardware, was selected for controls development and realization. The dSPACE real-time operating system collects sensor information; motor commands are transmitted over a PROFIBUS network to servo amplifiers and drive motor status is received over the same network. Custom designed position feedback loops, supplemented by feed forward force commands for enhanced performance, and algorithms to accommodate self-locking gearboxes (for safety), reside in dSPACE. To interface the dSPACE controller directly to absolute Heidenhain sensors with EnDat 2.2 protocol, a custom communication board was developed. This paper covers details of software and hardware, design choices and analysis, and supporting simulations (primarily Simulink).

Mock, Jason R.; Beno, Joe; Rafferty, Tom H.; Cornell, Mark E.

2010-07-01

328

THE DISCOVERY OF Y DWARFS USING DATA FROM THE WIDE-FIELD INFRARED SURVEY EXPLORER (WISE)  

SciTech Connect

We present the discovery of seven ultracool brown dwarfs identified with the Wide-field Infrared Survey Explorer (WISE). Near-infrared spectroscopy reveals deep absorption bands of H{sub 2}O and CH{sub 4} that indicate all seven of the brown dwarfs have spectral types later than UGPS J072227.51-054031.2, the latest-type T dwarf currently known. The spectrum of WISEP J182831.08+265037.8 is distinct in that the heights of the J- and H-band peaks are approximately equal in units of f{sub {lambda}}, so we identify it as the archetypal member of the Y spectral class. The spectra of at least two of the other brown dwarfs exhibit absorption on the blue wing of the H-band peak that we tentatively ascribe to NH{sub 3}. These spectral morphological changes provide a clear transition between the T dwarfs and the Y dwarfs. In order to produce a smooth near-infrared spectral sequence across the T/Y dwarf transition, we have reclassified UGPS 0722-05 as the T9 spectral standard and tentatively assign WISEP J173835.52+273258.9 as the Y0 spectral standard. In total, six of the seven new brown dwarfs are classified as Y dwarfs: four are classified as Y0, one is classified as Y0 (pec?), and WISEP J1828+2650 is classified as >Y0. We have also compared the spectra to the model atmospheres of Marley and Saumon and infer that the brown dwarfs have effective temperatures ranging from 300 K to 500 K, making them the coldest spectroscopically confirmed brown dwarfs known to date.

Cushing, Michael C.; Mainzer, A.; Eisenhardt, Peter R. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, MS 321-520, Pasadena, CA 91109 (United States); Kirkpatrick, J. Davy; Gelino, Christopher R.; Griffith, Roger L.; Marsh, Kenneth A.; Beichman, Charles A. [Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States); Skrutskie, Michael F. [Department of Astronomy, University of Virginia, Charlottesville, VA 22904 (United States); Burgasser, Adam J. [Center for Astrophysics and Space Science, University of California San Diego, La Jolla, CA 92093 (United States); Prato, Lisa A. [Lowell Observatory, 1400 West Mars Hill Road, Flagstaff, AZ 86001 (United States); Simcoe, Robert A. [Massachusetts Institute of Technology, 77 Massachusetts Avenue, Building 37, Cambridge, MA 02139 (United States); Marley, Mark S.; Freedman, Richard S. [NASA Ames Research Center, MS 254-3, Moffett Field, CA 94035 (United States); Saumon, D. [Los Alamos National Laboratory, MS F663, Los Alamos, NM 87545 (United States); Wright, Edward L., E-mail: michael.cushing@gmail.com [Department of Physics and Astronomy, UCLA, Los Angeles, CA 90095 (United States)

2011-12-10

329

THERMAL MODEL CALIBRATION FOR MINOR PLANETS OBSERVED WITH WIDE-FIELD INFRARED SURVEY EXPLORER/NEOWISE  

SciTech Connect

With the Wide-field Infrared Survey Explorer (WISE), we have observed over 157,000 minor planets. Included in these are a number of near-Earth objects, main-belt asteroids, and irregular satellites which have well measured physical properties (via radar studies and in situ imaging) such as diameters. We have used these objects to validate models of thermal emission and reflected sunlight using the WISE measurements, as well as the color corrections derived in Wright et al. for the four WISE bandpasses as a function of effective temperature. We have used 50 objects with diameters measured by radar or in situ imaging to characterize the systematic errors implicit in using the WISE data with a faceted spherical near-Earth asteroid thermal model (NEATM) to compute diameters and albedos. By using the previously measured diameters and H magnitudes with a spherical NEATM model, we compute the predicted fluxes (after applying the color corrections given in Wright et al.) in each of the four WISE bands and compare them to the measured magnitudes. We find minimum systematic flux errors of 5%-10%, and hence minimum relative diameter and albedo errors of {approx}10% and {approx}20%, respectively. Additionally, visible albedos for the objects are computed and compared to the albedos at 3.4 {mu}m and 4.6 {mu}m, which contain a combination of reflected sunlight and thermal emission for most minor planets observed by WISE. Finally, we derive a linear relationship between subsolar temperature and effective temperature, which allows the color corrections given in Wright et al. to be used for minor planets by computing only subsolar temperature instead of a faceted thermophysical model. The thermal models derived in this paper are not intended to supplant previous measurements made using radar or spacecraft imaging; rather, we have used them to characterize the errors that should be expected when computing diameters and albedos of minor planets observed by WISE using a spherical NEATM model.

Mainzer, A.; Masiero, J.; Bauer, J.; Ressler, M.; Eisenhardt, P. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Grav, T. [Department of Physics and Astronomy, Johns Hopkins University, 366 Bloomberg Center, 3400 N. Charles Street, Baltimore, MD 21218 (United States); Wright, E. [UCLA Astronomy, P.O. Box 91547, Los Angeles, CA 90095-1547 (United States); Cutri, R. M. [Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States); McMillan, R. S. [Lunar and Planetary Laboratory, University of Arizona, 1629 East University Blvd., Kuiper Space Science Bldg. 92, Tucson, AZ 85721-0092 (United States); Cohen, M., E-mail: amainzer@jpl.nasa.gov [Radio Astronomy Laboratory, 601 Campbell Hall, University of California, Berkeley, CA 94720 (United States)

2011-08-01

330

A deep and wide-field view at the IC 2944/2948 complex in Centaurus*  

NASA Astrophysics Data System (ADS)

We employed the ESO Max Planck Institute (MPI) wide-field camera (Baade et al.) and obtained deep images in the VIC pass-bands in the region of the IC 2944/2948 complex (l ˜ 294.8° b ˜ -1.6°), and complemented them with literature and archival data. We used this material to derive the photometric, spectroscopic and kinematic properties of the brightest (V < 16) stars in the region. The VI deep photometry on the other end, helped us to unravel the lower main sequence of a few, possibly physical, star groups in the area. Our analysis confirmed previous suggestions that the extinction towards this line of sight follows the normal law (RV = 3.1). We could recognize B-type stars spread in distance from a few hundred pc to at least 2 kpc. We found two young groups (age ˜ 3 Myr) located, respectively, at about 2.3 and 3.2 kpc from the Sun. They are characterized by a significant variable extinction (E(B - V) ranging from 0.28 to 0.45 mag), and host a significant pre-main-sequence population. We computed the initial mass functions for these groups and obtained slopes ? from -0.94 to -1.02 (e? = 0.3) in a scale where the classical Salpeter law is -1.35. We estimated the total mass of both main stellar groups in ˜1100 and ˜500 M?, respectively. Our kinematic analysis indicated that both groups of stars deviate from the standard rotation curve of the Milky Way, in line with literature results for this specific Galactic direction. Finally, along the same line of sight, we identified a third group of early-type stars located at ˜8 kpc from the Sun. This group might be located in the far side of the Sagittarius-Carina spiral arm.

Baume, G.; Rodríguez, M. J.; Corti, M. A.; Carraro, G.; Panei, J. A.

2014-09-01

331

Wide-field hard x-ray survey telescope: ProtoEXIST1  

NASA Astrophysics Data System (ADS)

We report our progress on the development of pixellated imaging CZT detector arrays for our first-generation balloon-borne wide-field hard X-ray (20 - 600 keV) telescope, ProtoEXIST1. Our ProtoEXIST program is a pathfinder for the High Energy Telescope (HET) on the Energetic X-ray Imaging Survey telescope (EXIST), a proposed implementation of the Black Hole Finder Probe. ProtoEXIST1 consists of four independent coded-aperture telescopes with close-tiled (~0.4 mm gaps) CZT detectors that preserve their 2.5mm pixel pitch. Multiple shielding/field-of-view configurations are planned to identify optimal geometry for the HET in EXIST. The primary technical challenge in ProtoEXIST is the development of large area, close-tiled modules of imaging CZT detectors (1000 cm2 for ProtoEXIST1), with all readout and control systems for the ASIC readout vertically stacked. We describe the overall telescope configuration of ProtoEXIST1 and review the current development status of the CZT detectors, from individual detector crystal units (DCUs) to a full detector module (DM). We have built the first units of each component for the detector plane and have completed a few Rev2 DCUs (2x2 cm2), which are under a series of tests. Bare DCUs (pre-crystal bonding) show high, uniform ASIC yield (~70%) and ~30% reduction in electronics noise compared to the Rev1 equivalent. A Rev1 DCU already achieved ~1.2% FWHM at 662 keV, and preliminary analysis of the initial radiation tests on a Rev2 DCU shows ~ 4 keV FWHM at 60 keV (vs. 4.7 keV for Rev1). We therefore expect about <=1% FWHM at 662 keV with the Rev2 detectors.

Hong, J.; Grindlay, J. E.; Chammas, N.; Allen, B.; Copete, A.; Said, B.; Burke, M.; Howell, J.; Gauron, T.; Baker, R. G.; Barthelmy, S. D.; Sheikh, S.; Gehrels, N.; Cook, W. R.; Burnham, J. A.; Harrison, F. A.; Collins, J.; Labov, S.; Garson, A., III; Krawczynski, H.

2007-09-01

332

Wide-field fluorescent microscopy and fluorescent imaging flow cytometry on a cell-phone.  

PubMed

Fluorescent microscopy and flow cytometry are widely used tools in biomedical research and clinical diagnosis. However these devices are in general relatively bulky and costly, making them less effective in the resource limited settings. To potentially address these limitations, we have recently demonstrated the integration of wide-field fluorescent microscopy and imaging flow cytometry tools on cell-phones using compact, light-weight, and cost-effective opto-fluidic attachments. In our flow cytometry design, fluorescently labeled cells are flushed through a microfluidic channel that is positioned above the existing cell-phone camera unit. Battery powered light-emitting diodes (LEDs) are butt-coupled to the side of this microfluidic chip, which effectively acts as a multi-mode slab waveguide, where the excitation light is guided to uniformly excite the fluorescent targets. The cell-phone camera records a time lapse movie of the fluorescent cells flowing through the microfluidic channel, where the digital frames of this movie are processed to count the number of the labeled cells within the target solution of interest. Using a similar opto-fluidic design, we can also image these fluorescently labeled cells in static mode by e.g. sandwiching the fluorescent particles between two glass slides and capturing their fluorescent images using the cell-phone camera, which can achieve a spatial resolution of e.g. - 10 ?m over a very large field-of-view of - 81 mm(2). This cell-phone based fluorescent imaging flow cytometry and microscopy platform might be useful especially in resource limited settings, for e.g. counting of CD4+ T cells toward monitoring of HIV+ patients or for detection of water-borne parasites in drinking water. PMID:23603893

Zhu, Hongying; Ozcan, Aydogan

2013-01-01

333

A Wide-field near- and Mid-infrared Census of Young Stars in NGC 6334  

NASA Astrophysics Data System (ADS)

This paper presents a study of the rate and efficiency of star formation in the NGC 6334 star-forming region. We obtained observations at J, H, and Ks taken with the NOAO Extremely Wide-Field Infrared Imager and combined them with observations taken with the Infrared Array Camera (IRAC) on the Spitzer Space Telescope at wavelengths = 3.6, 4.5, 5.8, and 8.0 ?m. We also analyzed previous observations taken at 24 ?m using the Spitzer MIPS camera as part of the MIPSGAL survey. We have produced a point source catalog with >700, 000 entries. We have identified 2283 young stellar object (YSO) candidates, 375 Class I YSOs, and 1908 Class II YSOs using a combination of existing IRAC-based color classification schemes that we have extended and validated to the near-IR for use with warm Spitzer data. We have identified multiple new sites of ongoing star formation activity along filamentary structures extending tens of parsecs beyond the central molecular ridge of NGC 6334. By mapping the extinction, we derived an estimate for the gas mass, 2.2 × 105 M ?. The heavy concentration of protostars along the dense filamentary structures indicates that NGC 6334 may be undergoing a "mini-starburst" event with ?SFR > 8.2 M ? Myr-1 pc-2 and SFE > 0.10. We have used these estimates to place NGC 6334 in the Kennicutt-Schmidt diagram to help bridge the gap between observations of local low-mass star-forming regions and star formation in other galaxies.

Willis, S.; Marengo, M.; Allen, L.; Fazio, G. G.; Smith, H. A.; Carey, S.

2013-12-01

334

NOTE: Multileaf collimator end leaf leakage: implications for wide-field IMRT  

NASA Astrophysics Data System (ADS)

The multi-leaf collimator (MLC) of a particular linear accelerator vendor (Millennium MLC, Varian Medical Systems, Palo Alto, CA, USA) has a maximum leaf extension of 14.5 cm. To achieve intensity modulated radiotherapy (IMRT) for fields wider than 14.5 cm all closed leaf pairs are restricted to placement inside the field. Due to the rounded leaf end design of the MLC end leaf leakage will occur in the treatment field. The implementation of direct aperture optimization in the IMRT module of a radiotherapy treatment planning system (Pinnacle, Philips Radiation Oncology Systems, Milpitas, CA) has facilitated the delivery of IMRT fields wider than 14.5 cm. The end leaf leakage of the Millennium MLC has been characterized for 6 MV photons using gafchromic and radiographic film, and the accuracy of the planning system verified. The maximum leakage measured for a single field was 0.39 cGy MU-1 for a 0 mm leaf gap and 0.51 cGy MU-1 for a 0.6 mm leaf gap. For a clinical IMRT field leaf end leakage contributed an additional 2-3 Gy over the course of treatment. The planning system underestimated the magnitude of end leaf leakage by 20-40%. The ability to deliver IMRT fields wider than 14.5 cm with the Millennium MLC has improved the efficiency and flexibility of IMRT treatments; however, significant extra dose can be introduced due to end leaf leakage. Caution should be exercised when delivering wide field IMRT as it is not a complete panacea. Any significant occurrences of end leaf leakage predicted by the planning system should be independently verified prior to delivery.

Hardcastle, N.; Metcalfe, P.; Ceylan, A.; Williams, M. J.

2007-11-01

335

Wide-field Fluorescent Microscopy and Fluorescent Imaging Flow Cytometry on a Cell-phone  

PubMed Central

Fluorescent microscopy and flow cytometry are widely used tools in biomedical research and clinical diagnosis. However these devices are in general relatively bulky and costly, making them less effective in the resource limited settings. To potentially address these limitations, we have recently demonstrated the integration of wide-field fluorescent microscopy and imaging flow cytometry tools on cell-phones using compact, lightweight, and cost-effective opto-fluidic attachments. In our flow cytometry design, fluorescently labeled cells are flushed through a microfluidic channel that is positioned above the existing cell-phone camera unit. Battery powered light-emitting diodes (LEDs) are butt-coupled to the side of this microfluidic chip, which effectively acts as a multi-mode slab waveguide, where the excitation light is guided to uniformly excite the fluorescent targets. The cell-phone camera records a time lapse movie of the fluorescent cells flowing through the microfluidic channel, where the digital frames of this movie are processed to count the number of the labeled cells within the target solution of interest. Using a similar opto-fluidic design, we can also image these fluorescently labeled cells in static mode by e.g. sandwiching the fluorescent particles between two glass slides and capturing their fluorescent images using the cell-phone camera, which can achieve a spatial resolution of e.g. ~ 10 ?m over a very large field-of-view of ~ 81 mm2. This cell-phone based fluorescent imaging flow cytometry and microscopy platform might be useful especially in resource limited settings, for e.g. counting of CD4+ T cells toward monitoring of HIV+ patients or for detection of water-borne parasites in drinking water. PMID:23603893

Zhu, Hongying; Ozcan, Aydogan

2013-01-01

336

Color and monochrome lensless on-chip imaging of Caenorhabditis elegans over a wide field-of-view  

PubMed Central

We demonstrate color and monochrome on-chip imaging of Caenorhabditis elegans samples over a wide field-of-view using incoherent lensless in-line holography. Digital reconstruction of the recorded lensless holograms rapidly creates the C. elegans images within <1 s over a field-of-view of >24 mm2. By digitally combining the reconstructed images at three different wavelengths (red, green and blue), color images of dyed samples are also acquired. This wide field-of-view and compact on-chip imaging modality also permits straightforward integration with microfluidic systems. PMID:20390127

Isikman, Serhan O.; Sencan, Ikbal; Mudanyali, Onur; Bishara, Waheb; Oztoprak, Cetin; Ozcan, Aydogan

2010-01-01

337

Current status of the Explosive Transient Camera. [automated sky survey instument sensitive to optical transients  

NASA Technical Reports Server (NTRS)

The current configuration and performance of the Explosive Transient Camera (ETC), a wide-field sky monitor capable of detecting short-timescale optical transients, are briefly reviewed, as are plans for future improvements. The primary objective of the ETC is to detect an optical transient that is spatially and temporally coincident with a gamma-ray burster. However, the ETC is sensitive to all sources of short-timescale optical transients and will conduct a systematic survey of the night sky for all optical transients. Results of preliminary observations of the night sky conducted since January 1991 are summarized, and long-term variability searches with the ETC are discussed.

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

1992-01-01

338

Near Earth Architectural Options for a Future Deep Space Optical Communications Network  

NASA Technical Reports Server (NTRS)

In the near future the National Aeronautics and Space Administration anticipates a significant increase in demand for long-haul communications services from deep space to Earth. Distances will range from 0.1 to 40 AU, with data rate requirements in the 1's to 1000's of Mbits/second. The near term demand is driven by NASA's Space Science Enterprise which wishes to deploy more capable instruments onboard spacecraft and increase the number of deep space missions. The long term demand is driven by missions with extreme communications challenges such as very high data rates from the outer planets, supporting sub-surface exploration, or supporting NASA's Human Exploration and Development of Space Enterprise beyond Earth orbit. Laser communications is a revolutionary communications technology that will dramatically increase NASA's ability to transmit information across the solar system. Lasercom sends information using beams of light and optical elements, such as telescopes and optical amplifiers, rather than RF signals, amplifiers, and antennas. This paper provides an overview of different network options at Earth to meet NASA's deep space lasercom requirements. It is based mainly on work done for the Mars Laser Communications Demonstration 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 reports preliminary conclusions from the Mars Lasercom Study conducted at MIT/LL and on additional work done for the Tracking and Data Relay Satellite System Continuation Study at GSFC. A lasercom flight terminal will be flown on the Mars Telesat Orbiter (MTO) to be launched by NASA in 2009, and will be the first high rate deep space demonstration of this revolutionary technology.

Edwards, B. L.; Liebrecht, P. E.; Fitzgerald, R. J.

2003-01-01

339

Removing cosmic-ray hits from multiorbit HST Wide Field Camera images  

NASA Technical Reports Server (NTRS)

We present an optimized algorithm that removes cosmic rays ('CRs') from multiorbit Hubble Space Telescope (HST) Wide Field/Planetary Camera ('WF/PC') images. It computes the image noise in every iteration from the WF/PC CCD equation. This includes all known sources of random and systematic calibration errors. We test this algorithm on WF/PC stacks of 2-12 orbits as a function of the number of available orbits and the formal Poissonian sigma-clipping level. We find that the algorithm needs greater than or equal 4 WF/PC exposures to locate the minimal sky signal (which is noticeably affected by CRs), with an optimal clipping level at 2-2.5 x sigma(sub Poisson). We analyze the CR flux detected on multiorbit 'CR stacks,' which are constructed by subtracting the best CR filtered images from the unfiltered 8-12 orbit average. We use an automated object finder to determine the surface density of CRS as a function of the apparent magnitude (or ADU flux) they would have generated in the images had they not been removed. The power law slope of the CR 'counts' (gamma approximately = 0.6 for N(m) m(exp gamma)) is steeper than that of the faint galaxy counts down to V approximately = 28 mag. The CR counts show a drop off between 28 less than or approximately V less than or approximately 30 mag (the latter is our formal 2 sigma point source sensitivity without spherical aberration). This prevents the CR sky integral from diverging, and is likely due to a real cutoff in the CR energy distribution below approximately 11 ADU per orbit. The integral CR surface density is less than or approximately 10(exp 8)/sq. deg, and their sky signal is V approximately = 25.5-27.0 mag/sq. arcsec, or 3%-13% of our NEP sky background (V = 23.3 mag/sq. arcsec), and well above the EBL integral of the deepest galaxy counts (B(sub J) approximately = 28.0 mag/sq. arcsec). We conclude that faint CRs will always contribute to the sky signal in the deepest WF/PC images. Since WFPC2 has approximately 2.7x lower read noise and a thicker CCD, this will result in more CR detections than in WF/PC, potentially affecting approximately 10%-20% of the pixels in multiorbit WFPC2 data cubes.

Windhorst, Rogier A.; Franklin, Barbara E.; Neuschaefer, Lyman W.

1994-01-01

340

The Software Design for the Wide-Field Infrared Explorer Attitude Control System  

NASA Technical Reports Server (NTRS)

The Wide-Field Infrared Explorer (WIRE), currently scheduled for launch in September 1998, is the fifth of five spacecraft in the NASA/Goddard Small Explorer (SMEX) series. This paper presents the design of WIRE's Attitude Control System flight software (ACS FSW). WIRE is a momentum-biased, three-axis stabilized stellar pointer which provides high-accuracy pointing and autonomous acquisition for eight to ten stellar targets per orbit. WIRE's short mission life and limited cryogen supply motivate requirements for Sun and Earth avoidance constraints which are designed to prevent catastrophic instrument damage and to minimize the heat load on the cryostat. The FSW implements autonomous fault detection and handling (FDH) to enforce these instrument constraints and to perform several other checks which insure the safety of the spacecraft. The ACS FSW implements modules for sensor data processing, attitude determination, attitude control, guide star acquisition, actuator command generation, command/telemetry processing, and FDH. These software components are integrated with a hierarchical control mode managing module that dictates which software components are currently active. The lowest mode in the hierarchy is the 'safest' one, in the sense that it utilizes a minimal complement of sensors and actuators to keep the spacecraft in a stable configuration (power and pointing constraints are maintained). As higher modes in the hierarchy are achieved, the various software functions are activated by the mode manager, and an increasing level of attitude control accuracy is provided. If FDH detects a constraint violation or other anomaly, it triggers a safing transition to a lower control mode. The WIRE ACS FSW satisfies all target acquisition and pointing accuracy requirements, enforces all pointing constraints, provides the ground with a simple means for reconfiguring the system via table load, and meets all the demands of its real-time embedded environment (16 MHz Intel 80386 processor with 80387 coprocessor running under the VRTX operating system). The mode manager organizes and controls all the software modules used to accomplish these goals, and in particular, the FDH module is tightly coupled with the mode manager.

Anderson, Mark O.; Barnes, Kenneth C.; Melhorn, Charles M.; Phillips, Tom

1998-01-01

341

Characterizing AGB stars in Wide-field Infrared Survey Explorer (WISE) bands  

NASA Astrophysics Data System (ADS)

Aims: Since asymptotic giant branch (AGB) stars are bright and extended infrared objects, most Galactic AGB stars saturate the Wide-field Infrared Survey Explorer (WISE) detectors and therefore the WISE magnitudes that are restored by applying point-spread-function fitting need to be verified. Statistical properties of circumstellar envelopes around AGB stars are discussed on the basis of a WISE AGB catalog verified in this way. Methods: We cross-matched an AGB star sample with the WISE All-Sky Source Catalog and the Two Mircon All Sky Survey catalog. Infrared Space Observatory (ISO) spectra of a subsample of WISE AGB stars were also exploited. The dust radiation transfer code DUSTY was used to help predict the magnitudes in the W1 and W2 bands, the two WISE bands most affected by saturation, for calibration purpose, and to provide physical parameters of the AGB sample stars for analysis. Results: DUSTY is verified against the ISO spectra to be a good tool to reproduce the spectral energy distributions of these AGB stars. Systematic magnitude-dependent offsets have been identified in WISE W1 and W2 magnitudes of the saturated AGB stars, and empirical calibration formulas are obtained for them on the basis of 1877 (W1) and 1558 (W2) AGB stars that are successfully fit with DUSTY. According to the calibration formulas, the corrections for W1 at 5 mag and W2 at 4 mag are -0.383 and 0.217 mag, respectively. In total, we calibrated the W1/W2 magnitudes of 2390/2021 AGB stars. The model parameters from the DUSTY and the calibrated WISE W1 and W2 magnitudes are used to discuss the behavior of the WISE color-color diagrams of AGB stars. The model parameters also reveal that O-rich AGB stars with opaque circumstellar envelopes are much rarer than opaque C-rich AGB stars toward the anti-Galactic center direction, which we attribute to the metallicity gradient of our Galaxy. The synthetic photometry and input parameters for the model grid 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/564/A84

Lian, Jianhui; Zhu, Qingfeng; Kong, Xu; He, Jinhua

2014-04-01

342

UV-curable hybrid polymers for optical applications: technical challenges, industrial solutions, and future developments  

NASA Astrophysics Data System (ADS)

Advanced micro- and nanofabrication processes are constantly evolving from academic R&D environment towards real production technology. Therefore, the availability of suitable polymers for optical applications plays a crucial role to satisfy not only application based requirements but also the compatibility to industrial production technologies. In this context, UV-curable hybrid polymers, i.e. inorganic-organic materials obtained by sol-gel chemistry, were recently implemented into mass production environment, e.g. for micro-lenses in mobile device applications. In this contribution, we report on the development of innovative hybrid polymers and their tailoring towards an easy and fast processing with reliable and reproducible performance output for industrial large-scale production. Based on a discussion on standard process parameters with respect to optimize the material's performance, the technical demands of industrial manufacture to the hybrid polymers will be subsequently reviewed by giving selective examples. This will be complemented by a brief description of current R&D activities adapting hybrid polymers to future patterning technologies.

Gruetzner, G.; Klein, J.; Vogler, M.; Schleunitz, A.

2014-03-01

343

Aluminum\\/ammonia heat pipe gas generation and long term system impact for the Space Telescope's Wide Field Planetary Camera  

Microsoft Academic Search

In the Space Telecope's Wide Field Planetary Camera (WFPC) project, eight heat pipes (HPs) are used to remove heat from the camera's inner electronic sensors to the spacecraft's outer, cold radiator surface. For proper device functioning and maximization of the signal-to-noise ratios, the Charge Coupled Devices (CCD's) must be maintained at -95 C or lower. Thermoelectric coolers (TEC's) cool the

J. A. Jones

1983-01-01

344

BINARITY IN BROWN DWARFS: T DWARF BINARIES DISCOVERED WITH THE HUBBLE SPACE TELESCOPE WIDE FIELD PLANETARY CAMERA 2  

E-print Network

BINARITY IN BROWN DWARFS: T DWARF BINARIES DISCOVERED WITH THE HUBBLE SPACE TELESCOPE WIDE FIELD, respectively. These close separations are similar to those found in previous brown dwarf binary searches other brown dwarf binary searches. Using the statistical models of Weinberg, Shapiro, & Wasserman, we

Burgasser, Adam J.

345

ProtoEXIST: The Development of Advanced Tiled CZT Detector Planes for Wide Field Hard X-Ray Survey Telescope  

NASA Astrophysics Data System (ADS)

ProtoEXIST is a technology development program for a coded aperture hard X-ray telescope with a large area (1-5 m^2) CZT detector plane for use in a future hard X-ray wide field sky monitor and survey telescope. The successful flight of the ProtoEXIST1 (P1) coded-aperture telescope concluded the first phase of the program on October 9, 2009. The black hole binary Cyg X-1 was imaged and its spectrum measured at the end of the (6h) flight. The P1 detector plane is comprised of a 8x8 array of detector crystal units (DCUs); each made up of a single 20 mm x 20 mm, 5 mm thick Redlen CZT crystal with a 8x8 pixilated anode (pixel pitch of 2.5 mm) bonded to an interposer board connecting each of the individual 64 anode pixels to a single input channel on a RadNET ASIC, forming a 256 cm^2 contiguous CZT imaging array with 4096 individual pixels. P1 was successfully recovered and has undergone further characterization in the interim. The program continues with the ongoing development ProtoEXIST2 (P2) utilizing a closely tiled 8x8 array of DCUs now with a reduced anode pixel pitch of 0.6 mm. Each DCU in P2 will consist of a CZT crystal, identical to that utilized in P1 now with a 32x32 pixelated anode, directly bonded to a single NuSTAR ASIC (Nu-ASIC). The fully assembled P2 imaging detector will be comprised of a semi-contiguous 256x256 array of pixels on 256 cm^2 of CZT. With its finer pixelation the P2 detector plane will enable 5' (FWHM) imaging with a 70 cm focal length and will be flown side-by-side with P1 from Ft. Sumner in the Spring of 2012. Results from the characterization of the P1 detector are discussed as well as current progress in the development of the P2 detector plane.

Allen, Branden; Hong, J.; Grindlay, J.; Barthelmy, S.; Baker, R.

2011-05-01

346

Stellar photometry in the inner bulge of M31 using the Hubble Space Telescope wide field camera  

NASA Technical Reports Server (NTRS)

We present photometry of two fields in the M31 bulge imaged with the Hubble Space Telescope (HST) Wide-Field Camara (WFC). The nuclear field (r less than 40 arcsecs = 150 pc) giant branch extends to I = 19.5, M(sub I) = -5 (Cousins system), a full 0.9 mag brighter than the giant-branch tips of metal-poor Galactic globular clusters and M31 halo fields. This is also approximately = 1.5 mag brighter than the giant branches of metal-rich Galactic globular clusters, but is no brighter than Mould's (1986) M31 bulge field 1 kpc from the nucleus. The data also suggest that the brighter stars may be preferentially concentrated to the center. The 648 luminous stars detected in 2 x 10(exp 9) solar luminosity is approximately = 25% that expected from a hypothetical population of evolved asymptotic giant branch (AGB) stars with lifetimes approximately = 10(exp 5) yr, with the cautionary note that we are near the detection limit. The number of bright stars is also consistent with the progeny of blue stragglers, if one uses a lifetime for the thermal-pulsing AGB of 2 x 10(exp 6) yr. We strongly caution that incompleteness becomes severe below I = 19.9 mag and that future surveys are likely to find numbers of bright stars too large to accomodate the blue straggler progeny hypothesis. We have imaged an additional field 2 arcmin = 500 pc south of the nucleus. The brightest stars in this field are also I = 19.5, but bright stars appear less numerous than in the nuclear field. If the population resembles that of the Galactic bulge, then M(sub bol) = -4.5 is a lower limit to the giant-branch tip luminosity; infrared studies should reveal stars 0.5 mag or more brighter. Either high-metallicity or (more likely) age approximately = 10 Gyr may be responsible for the presence of these luminous AGB stars. These observations confirm that previous ground-based infrared studies (e.g., Rich & Mould 1991) very likely detect an extended giant branch and not spurious luminous stars caused by crowding or disk contamination. However, published integrated colors for the M31 bulge/nucleus are extremely red, making it difficult to accomodate a young or intermediate-age population.

Rich, R. M.; Mighell, K. J.

1995-01-01

347

ProtoEXIST: balloon-borne technology development for wide-field hard X-ray imaging  

NASA Astrophysics Data System (ADS)

We report on the development of the ProtoEXIST balloon-borne experiment for development of wide-field coded aperture imaging with high spatial resolution imaging Cd-Zn-Te (CZT) arrays in close-tiled, large area configurations. ProtoEXIST1 will incorporate two coded aperture telescopes, each with 16 x 16cm close-tiled imaging CZT with 2.5mm pixels that maintain registration across the full detector. The detector plane incorporates new-technology low powered ASIC readout on each 20 x 20 x 5mm CZT crystal. A 2 x 4 array of such crystals are closetiled on a single board (DCA) with vertical integration to a controlling and readout-enabling FPGA. Detector readout modes can be commanded through the FPGA and selected in flight: from simple peak pixel, to peak plus neighbor pixels to larger pixel-selected modes, which will improve spatial/spectral resolution as well as allow for future tests of Compton imaging. The full readout consists of a 2 x 4 array of DCAs for each of the two telescopes. The detector plane is shielded from below by an active shield (2cm CsI) on one telescope vs. an equivalent graded-passive shield on the other to enable direct imaging comparisons of background rejection in a balloon environment. Both telescopes incorporate otherwise identical graded-passive side shields and laminated coded aperture masks (5mm pixels, laser-cut in W sheet). The telescopes each have 20o x 20o fields of view (FWHM), with 21arcmin resolution across the field. The ProtoEXIST gondola is derived from the old Harvard EXITE gondola but now with new pointing system and daytime star camera as developed at MSFC for the HERO balloon payload. A first flight is planned for September/October, 2008. Tests will include not only the first tests of this multipixel, controllable ASIC-readout system but also tests of the scanning coded aperture imaging as planned for the proposed EXIST mission. Followup flight(s) will test the higher-spatial resolution CZT imager (0.6mm pixels) now planned for the full EXIST mission.

Grindlay, Jonathan

348

Satellite Ocean Biology: Past, Present, Future  

NASA Technical Reports Server (NTRS)

Since 1978 when the first satellite ocean color proof-of-concept sensor, the Nimbus-7 Coastal Zone Color Scanner, was launched, much progress has been made in refining the basic measurement concept and expanding the research applications of global satellite time series of biological and optical properties such as chlorophyll-a concentrations. The seminar will review the fundamentals of satellite ocean color measurements (sensor design considerations, on-orbit calibration, atmospheric corrections, and bio-optical algorithms), scientific results from the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) and Moderate resolution Imaging Spectroradiometer (MODIS) missions, and the goals of future NASA missions such as PACE, the Aerosol, Cloud, Ecology (ACE), and Geostationary Coastal and Air Pollution Events (GeoCAPE) missions.

McClain, Charles R.

2012-01-01

349

A New Variational Method for Erythrocyte Velocity Estimation in Wide-Field Imaging In Vivo  

Microsoft Academic Search

Measuring erythrocyte velocity in individual mi- crovessels has important applications for biomedical and func- tional imaging. Recent multiphoton fluorescence microscopy approaches require injecting fluorescent tracers; moreover, only one or few vessels can be imaged at a time. To overcome these shortcomings, we used CCD-based optical imaging of intrinsic absorption changes in macroscopic vascular networks to record erythrocytes' trajectories over several

Thomas Deneux; Olivier Faugeras; Sylvain Takerkart; Guillaume S. Masson; Ivo Vanzetta

2011-01-01

350

Image-based calibration of a deformable mirror in wide-field microscopy.  

PubMed

Optical aberrations limit resolution in biological tissues, and their influence is particularly large for promising techniques such as light-sheet microscopy. In principle, image quality might be improved by adaptive optics (AO), in which aberrations are corrected by using a deformable mirror (DM). To implement AO in microscopy, one requires a method to measure wavefront aberrations, but the most commonly used methods have limitations for samples lacking point-source emitters. Here we implement an image-based wavefront-sensing technique, a variant of generalized phase-diverse imaging called multiframe blind deconvolution, and exploit it to calibrate a DM in a light-sheet microscope. We describe two methods of parameterizing the influence of the DM on aberrations: a traditional Zernike expansion requiring 1040 parameters, and a direct physical model of the DM requiring just 8 or 110 parameters. By randomizing voltages on all actuators, we show that the Zernike expansion successfully predicts wavefronts to an accuracy of approximately 30 nm (rms) even for large aberrations. We thus show that image-based wavefront sensing, which requires no additional optical equipment, allows a simple but powerful method to calibrate a deformable optical element in a microscope setting. PMID:20390001

Turaga, Diwakar; Holy, Timothy E

2010-04-10

351

Foveated endoscope objective design to combine high resolution with wide field of view  

NASA Astrophysics Data System (ADS)

There is always a tradeoff between resolution and Field of View (FOV) in an imaging system. This limit can be due to the number of pixels in the detector, however a fundamental limit also exists in any optical system called the Space Bandwidth Product (SBP) which scales as the FOV area divided by the area of the diffraction limited spot. The SBP can only be increased by increasing the size of the optical system. In applications where the size of the optical system is constrained such as endoscopes, the SBC will ultimately limit the resolution or FOV. However, there is a way to provide both high resolution and a wide FOV without changing the total number of pixels in the image. The technique is called foveated imaging because is mimics this characteristic of the human eye in which the fovea has a higher resolution at the center of the FOV than the surrounding retina. A similar effect can be achieved optically by introducing a large amount of barrel distortion in the lens design. The result is an effective increase in the magnification at the center of the FOV, and reduced resolution but larger angular sampling at the edge. The stretching effect of the distortion can be compensated for computationally to provide an onscreen display that is not distorted, but merely appears blurred at the edges. Such an objective will enable for endomicroscopy while still providing "peripheral vision" to allow endoscopists to navigate and locate regions of interest.

Rogers, Jeremy D.; Tkaczyk, Tomasz T.; Descour, Michael R.

2010-02-01

352

Orientation imaging of single molecules by wide-field epifluorescence microscopy  

E-print Network

for an immersion mirror objective used for imaging within a cryostat at low temperature. Here we show that this con with a high-numerical-aperture objective are taken into account. © 2003 Optical Society of America OCIS codes measurements. In what follows, we summarize only the research that was performed at room temperature and under

Enderlein, Jörg

353

A wide field of view radar for Sense and Avoid on UAV using space coloring waveforms  

Microsoft Academic Search

Up to now, UAV are employed in crisis or war times. For training purposes, some areas are especially attributed for UAV deployment in a limited space area and in a limited time slot. In the future, both for emerging civilian applications and for training purpose, these limitations will no longer be acceptable and UAV will have to be inserted in

Stéphane KEMKEMIAN; Myriam NOUVEL-FIANI; Pascal CORNIC; Patrick GARREC

2010-01-01

354

A wide field of view force protection system for ground vehicles  

NASA Astrophysics Data System (ADS)

The latest generation of heavily armored vehicles and the proliferation of IEDs in urban combat environments dictate that electro-optical systems play a greater role in situational awareness for ground vehicles. FLIR systems has been addressing the needs of the ground vehicle community by developing unique sensor systems combining thermal imaging and electro-optical sensors, advanced image processing, and networking capabilities into compact, cost effective packages. This paper will discuss one of those new products, the WideEye II. The WideEye II combines long wave infrared and electro-optical sensors in a 180 degree field of view, single integrated package to meet the critical needs of the warfighter. It includes seamless electronic stitching of the 180 degree image, and state of the art networking capability to allow it to be operated standalone or to be fully integrated with modern combat vehicle systems. The paper will discuss system tradeoffs and capabilities of this new product and show potential applications for its use.

Way, Scott; Archer, Cynthia; Jolivet, Noel; Cannon, Bruce; Hansen, Joel; Holt, Jordon; Olsen, Steven; Sarao, Jeremy

2009-05-01

355

Wide field-of-view target detection and simultaneous narrow field of view target analysis  

NASA Astrophysics Data System (ADS)

Protecting national borders, military and industrial complexes, national Infrastructure and high-value targets is critical to national security. Traditional solutions use a combination of ground surveillance radar, motion detection systems and video surveillance systems. Our development objective was to provide wide area 360-degree surveillance and ground-moving target detection using a passive optical system. In order to meet this objective, the development of an optical system capable of wide-area surveillance with intelligent cueing, high-resolution tracking and target identification is required. The predominant approach to optical surveillance has traditionally been gimbaled narrow field-of-view systems. These systems miss the majority of events occurring around them because of their inability to focus on anything other than a single event or object at any one time. Details of the system requirements definition, design trade studies and selected design configurations are discussed. The experimental results obtained during the current development phase have provided consistently high quality images and enhanced situational awareness. A summary of field validation methods and results is provided.

Nichols, Richard W.; Miller, Geoffrey M.

2009-05-01

356

A 3% Solution: Determination of the Hubble Constant with the Hubble Space Telescope and Wide Field Camera 3  

NASA Astrophysics Data System (ADS)

We use the Wide Field Camera 3 (WFC3) on the Hubble Space Telescope (HST) to determine the Hubble constant from optical and infrared observations of over 600 Cepheid variables in the host galaxies of eight recent Type Ia supernovae (SNe Ia), providing the calibration for a magnitude-redshift relation based on 253 SNe Ia. Increased precision over past measurements of the Hubble constant comes from five improvements: (1) more than doubling the number of infrared observations of Cepheids in the nearby SN hosts; (2) increasing the sample size of ideal SN Ia calibrators from six to eight; (3) increasing by 20% the number of Cepheids with infrared observations in the megamaser host NGC 4258 (4) reducing the difference in the mean metallicity of the Cepheid comparison samples between NGC 4258 and the SN hosts from ?log [O/H] = 0.08 to 0.05; and (5) calibrating all optical Cepheid colors with a single camera, WFC3, to remove cross-instrument zero-point errors. The result is a reduction in the uncertainty in H 0 due to steps beyond the first rung of the distance ladder from 3.5% to 2.3%. The measurement of H 0 via the geometric distance to NGC 4258 is 74.8 ± 3.1 km s-1 Mpc-1, a 4.1% measurement including systematic uncertainties. Better precision independent of the distance to NGC 4258 comes from the use of two alternative Cepheid absolute calibrations: (1) 13 Milky Way Cepheids with trigonometric parallaxes measured with HST/fine guidance sensor and Hipparcos and (2) 92 Cepheids in the Large Magellanic Cloud for which multiple accurate and precise eclipsing binary distances are available, yielding 74.4 ± 2.5 km s-1 Mpc-1, a 3.4% uncertainty including systematics. Our best estimate uses all three calibrations but a larger uncertainty afforded from any two: H 0 = 73.8 ± 2.4 km s-1 Mpc-1 including systematic errors, corresponding to a 3.3% uncertainty. The improved measurement of H 0, when combined with the Wilkinson Microwave Anisotropy Probe (WMAP) 7 year data, results in a tighter constraint on the equation-of-state parameter of dark energy of w = -1.08 ± 0.10. It also rules out the best-fitting gigaparsec-scale void models, posited as an alternative to dark energy. The combined H 0 + WMAP results yield N eff = 4.2 ± 0.7 for the number of relativistic particle species in the early universe, a low-significance excess for the value expected from the three known neutrino flavors. 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.

Riess, Adam G.; Macri, Lucas; Casertano, Stefano; Lampeitl, Hubert; Ferguson, Henry C.; Filippenko, Alexei V.; Jha, Saurabh W.; Li, Weidong; Chornock, Ryan

2011-04-01

357

A 3% SOLUTION: DETERMINATION OF THE HUBBLE CONSTANT WITH THE HUBBLE SPACE TELESCOPE AND WIDE FIELD CAMERA 3  

SciTech Connect

We use the Wide Field Camera 3 (WFC3) on the Hubble Space Telescope (HST) to determine the Hubble constant from optical and infrared observations of over 600 Cepheid variables in the host galaxies of eight recent Type Ia supernovae (SNe Ia), providing the calibration for a magnitude-redshift relation based on 253 SNe Ia. Increased precision over past measurements of the Hubble constant comes from five improvements: (1) more than doubling the number of infrared observations of Cepheids in the nearby SN hosts; (2) increasing the sample size of ideal SN Ia calibrators from six to eight; (3) increasing by 20% the number of Cepheids with infrared observations in the megamaser host NGC 4258; (4) reducing the difference in the mean metallicity of the Cepheid comparison samples between NGC 4258 and the SN hosts from {Delta}log [O/H] = 0.08 to 0.05; and (5) calibrating all optical Cepheid colors with a single camera, WFC3, to remove cross-instrument zero-point errors. The result is a reduction in the uncertainty in H{sub 0} due to steps beyond the first rung of the distance ladder from 3.5% to 2.3%. The measurement of H{sub 0} via the geometric distance to NGC 4258 is 74.8 {+-} 3.1 km s{sup -1} Mpc{sup -1}, a 4.1% measurement including systematic uncertainties. Better precision independent of the distance to NGC 4258 comes from the use of two alternative Cepheid absolute calibrations: (1) 13 Milky Way Cepheids with trigonometric parallaxes measured with HST/fine guidance sensor and Hipparcos and (2) 92 Cepheids in the Large Magellanic Cloud for which multiple accurate and precise eclipsing binary distances are available, yielding 74.4 {+-} 2.5 km s{sup -1} Mpc{sup -1}, a 3.4% uncertainty including systematics. Our best estimate uses all three calibrations but a larger uncertainty afforded from any two: H{sub 0} = 73.8 {+-} 2.4 km s{sup -1} Mpc{sup -1} including systematic errors, corresponding to a 3.3% uncertainty. The improved measurement of H{sub 0}, when combined with the Wilkinson Microwave Anisotropy Probe (WMAP) 7 year data, results in a tighter constraint on the equation-of-state parameter of dark energy of w = -1.08 {+-} 0.10. It also rules out the best-fitting gigaparsec-scale void models, posited as an alternative to dark energy. The combined H{sub 0} + WMAP results yield N{sub eff} = 4.2 {+-} 0.7 for the number of relativistic particle species in the early universe, a low-significance excess for the value expected from the three known neutrino flavors.

Riess, Adam G. [Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218 (United States); Macri, Lucas [George P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy, Department of Physics and Astronomy, Texas A and M University, 4242 TAMU, College Station, TX 77843-4242 (United States); Casertano, Stefano; Ferguson, Henry C. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Lampeitl, Hubert [Institute of Cosmology and Gravitation, University of Portsmouth, Portsmouth PO1 3FX (United Kingdom); Filippenko, Alexei V.; Li Weidong [Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States); Jha, Saurabh W. [Department of Physics and Astronomy, Rutgers University, 136 Frelinghuysen Road, Piscataway, NJ 08854 (United States); Chornock, Ryan, E-mail: ariess@stsci.edu [Harvard/Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

2011-04-01

358

Radiation tolerance qualification for maintenance tasks in the future fusion reactors: from fibre-optic components to robust data links  

Microsoft Academic Search

The future International Thermonuclear Experimental Reactor (ITER) requires remote handling tools for its maintenance that will operate in a harsh environment. The numerous instrumentation cables for this maintenance equipment call for (de)multiplexing solutions, in order to reduce the umbilical size. Fibre-optic data links, using commercial-off-the-shelf (COTS) components, are seriously considered as a radiation tolerant solution, offering wavelength encoded multiplexing possibilities.

M. Van Uffelen; A. Fernandez Fernandez; B. Brichard; F. Berghmans; M. Decréton

2003-01-01

359

Application of wide-field optical coherence tomography to monitoring of viability of rat brain in vivo  

NASA Astrophysics Data System (ADS)

We investigated the feasibility of OCT in monitoring the viability of the brain. It was confirmed that after an overdose of pentobarbital sodium salt for an euthanasia, the OCT signal intensity increased before cardiac arrest and finally became 2.7 times, and by periodically changing the tissue temperature from 20 to 32 °C in vivo, average correlation coefficients between the ratio of signal intensity (RSI) and temperature were determined to be -0:42 to -0:50. RSI reversibly changed with subsequent variations of temperatures and finally increased rapidly just before cardiac arrest. These results indicate that RSI could correspond to decreases in viability.

Sato, Manabu; Nishidate, Izumi

2014-05-01

360

FLAMINGOS-2: the facility near-infrared wide-field imager and multi-object spectrograph for Gemini  

NASA Astrophysics Data System (ADS)

We report on the design, on-sky performance, and status of the FLAMINGOS-2 instrument - the fully-cryogenic facility near-infrared imager and multi-object spectrograph for the Gemini 8-meter telescopes. FLAMINGOS-2 has a refractive all-spherical optical system providing 0.18-arcsecond pixels and a 6.2-arcminute circular field-of-view on a 2048x2048- pixel HAWAII-2 0.9-2.4 ?m detector array. A slit/decker wheel mechanism allows the selection of up to 9 multi-object laser-machined plates or 3 long slits for spectroscopy over a 6x2-arcminute field of view, and selectable grisms provide resolutions from ~1300 to ~3000 over the entire spectrograph bandpass. FLAMINGOS-2 is also compatible with the Gemini Multi-Conjugate Adaptive Optics system, providing multi-object spectroscopic capabilities over a 3x1-arcminute field with high spatial resolution (0.09-arcsec/pixel). We review the designs of optical, mechanical, electronics, software, and On-Instrument WaveFront Sensor subsystems. We also present the on-sky performance measured during acceptance testing in 2009, as well as current status of the project and future plans.

Eikenberry, Stephen; Bandyopadhyay, Reba; Bennett, J. Greg; Bessoff, Aaron; Branch, Matt; Charcos, Miguel; Corley, Richard; Dewitt, Curtis; Eriksen, John-David; Elston, Richard; Frommeyer, Skip; Gonzalez, Anthony; Hanna, Kevin; Herlevich, Michael; Hon, David; Julian, Jeff; Julian, Roger; Lasso, Nestor; Marin-Franch, Antonio; Marti, Jose; Murphey, Charlie; Raines, S. N.; Rambold, William; Rashkind, David; Warner, Craig; Leckie, Brian; Gardhouse, W. R.; Fletcher, Murray; Hardy, Tim; Dunn, Jennifer; Wooff, Robert; Pazder, John

2012-09-01

361

Hubble Space Telescope Wide Field Planetary Camera 2 Observations of Neptune  

NASA Technical Reports Server (NTRS)

Two groups have recently used the Hubble Space Telescope (HST) Wide Field Planetary Camera 2 (WFPC 2) to acquire new high-resolution images of the planet Neptune. Members of the WFPC-2 Science Team, lead by John Trauger, acquired the first series of images on 27 through 29 June 1994. These were the highest resolution images of Neptune taken since the Voyager-2 flyby in August of 1989. A more comprehensive program is currently being conducted by Heidi Hammel and Wes Lockwood. These two sets of observations are providing a wealth of new information about the structure, composition, and meteorology of this distant planet's atmosphere.

Neptune is currently the most distant planet from the sun, with an orbital radius of 4.5 billion kilometers (2.8 billion miles, or 30 Astronomical Units). Even though its diameter is about four times that of the Earth (49,420 vs. 12,742 km), ground-based telescopes reveal a tiny blue disk that subtends less than 1/1200 of a degree (2.3 arc-seconds). Neptune has therefore been a particularly challenging object to study from the ground because its disk is badly blurred by the Earth's atmosphere. In spite of this, ground-based astronomers had learned a great deal about this planet since its position was first predicted by John C. Adams and Urbain Leverrier in 1845. For example, they had determined that Neptune was composed primarily of hydrogen and helium gas, and that its blue color caused by the presence of trace amounts of the gas methane, which absorbs red light. They had also detected bright cloud features whose brightness changed with time, and tracked these clouds to infer a rotation period between 17 and 22 hours.

When the Voyager-2 spacecraft flew past the Neptune in 1989, its instruments revealed a surprising array of meteorological phenomena, including strong winds, bright, high-altitude clouds, and two large dark spots attributed to long-lived giant storm systems. These bright clouds and dark spots were tracked as they moved across the planet's disk, revealing wind speeds as large as 325 meters per second (730 miles per hour). The largest of the giant, dark storm systems, called the 'Great Dark Spot', received special attention because it resembled Jupiter's Great Red Spot, a storm that has persisted for more than three centuries. The lifetime of Neptune's Great Dark Spot could not be determined from the Voyager data alone, however, because the encounter was too brief. Its evolution was impossible to monitor with ground-based telescopes, because it could not be resolved on Neptune's tiny disk, and its contribution to the disk-integrated brightness of Neptune confused by the presence of a rapidly-varying bright cloud feature, called the 'Bright Companion' that usually accompanied the Great Dark spot.

The repaired Hubble Space Telescope provides new opportunities to monitor these and other phenomena in the atmosphere of the most distant planet. Images taken with WFPC-2's Planetary Camera (PC) can resolve Neptune's disk as well as most ground-based telescopes can resolve the disk of Jupiter. The spatial resolution of the HST WFPC-2 images is not as high as that obtained by the Voyager-2 Narrow-Angle Camera during that spacecraft's closest approach to Neptune, but they have a number of other assets that enhance their scientific value, including improved ultra-violet and infrared sensitivity, better signal-to-noise, and, and greater photometric accuracy.

The images of Neptune acquired by the WFPC-2 Science team in late June clearly demonstrate these capabilities. The side of the planet facing the Earth at the start of the program (11:36 Universal Time on July 27) was imaged in color filters spanning the ultraviolet (255 and 300-nm), visible (467, 588, 620, and 673- nm), and near-infrared (890-nm) parts of the spectrum. The planet then rotated 180 degrees in longitude, and the opposite hemisphere was imaged in a subset of these colors (300, 467, 588, 620, and 673-nm). The HST/WFPC-2 program more recently conducted by Hammel and Lockwood provides better lo

1995-01-01

362

A Search for a Distant Companion to the Sun with the Wide-field Infrared Survey Explorer  

NASA Astrophysics Data System (ADS)

I have used multi-epoch astrometry from the Wide-field Infrared Survey Explorer to perform a search for a distant companion to the Sun via its parallactic motion. I have not found an object of this kind down to W2 = 14.5. This limit corresponds to analogs of Saturn and Jupiter at 28,000 and 82,000 AU, respectively, according to models of the Jovian planets by Fortney and coworkers. Models of brown dwarfs by Burrows and coworkers predict fainter fluxes at a given mass for the age of the solar system, producing a closer distance limit of 26,000 AU for a Jupiter-mass brown dwarf. These constraints exclude most combinations of mass and separation at which a solar companion has been suggested to exist by various studies over the years. Based on data from the Wide-field Infrared Survey Explorer and the Two Micron All-Sky Survey.

Luhman, K. L.

2014-01-01

363

Problems with twilight/supersky flat-field for wide-field robotic telescopes and the solution  

NASA Astrophysics Data System (ADS)

Twilight/night sky images are often used for flat-fielding CCD images, but the brightness gradient in twilight/ night sky causes problems of accurate flat-field correction in astronomical images for wide-field telescopes. Using data from the Antarctic Survey Telescope (AST3), we found that when the sky brightness gradient is minimum and stable, there is still a gradient of 1% across AST3's field-of-view of 4.3 square degrees. We tested various approaches to remove the varying gradients in individual flat-field images. Our final optimal method can reduce the spatially dependent errors caused by the gradient to the negligible level. We also suggest a guideline of flat-fielding using twilight/night sky images for wide-field robotic autonomous telescopes.

Wei, Peng; Shang, Zhaohui; Ma, Bin; Zhao, Cheng; Hu, Yi; Liu, Qiang

2014-08-01

364

Method of achieving a wide field-of-view head-mounted display with small distortion.  

PubMed

We present a method of achieving a wide-angle, lightweight, optical see-through, distortion-free head-mounted display (HMD) by using two similar ellipsoids. An HMD that achieves a single channel field-of-view (FOV) of 120°×120° with a 6 mm eye box and a total binocular FOV of 160°×120° with an 80° field overlap is designed as an example. This method can solve the complex tiling problem and the distortion problem of other catadioptric structures. This structure is used to offset distortion and correct aberrations. PMID:23938968

Yang, Jianming; Liu, Weiqi; Lv, Weizhen; Zhang, Daliang; He, Fei; Wei, Zhonglun; Kang, Yusi

2013-06-15

365

Nanoscale topography and spatial light modulator characterization using wide-field quantitative phase imaging.  

PubMed

We demonstrate an optical technique for large field of view quantitative phase imaging of reflective samples. It relies on a common-path interferometric design, which ensures high stability without the need for active stabilization. The technique provides single-shot, full-field and robust measurement of nanoscale topography of large samples. Further, the inherent stability allows reliable measurement of the temporally varying phase retardation of the liquid crystal cells, and thus enables real-time characterization of spatial light modulators. The technique's application potential is validated through experimental results. PMID:24663633

Rajshekhar, Gannavarpu; Bhaduri, Basanta; Edwards, Chris; Zhou, Renjie; Goddard, Lynford L; Popescu, Gabriel

2014-02-10

366

A wide field corrector with loss-less and purely passive atmospheric dispersion correction  

NASA Astrophysics Data System (ADS)

A 2.5 degree field diameter corrector lens design for the Cassegrain focus of the VISTA 4 meter telescope is presented. It comprises four single elements of glasses with high UV transmission, all axi-symmetric for operation at the zenith. One element is displaced laterally to provide atmospheric dispersion correction. A key feature, especially beneficial for the VISTA application, is that the ADC element can be mounted so it is driven simply by gravity; thus its operation needs no motors, encoders, cabling, or software control. A simple mechanical design to achieve this and the optical performance details are described.

Gillingham, Peter; Saunders, Will

2014-07-01

367

An improved wide-field camera for imaging Earth's plasmasphere at 30.4 nm  

NASA Astrophysics Data System (ADS)

The Extreme Ultraviolet Imager (IMAGE/EUV) aboard NASA's IMAGE mission studied the distribution of singly ionized helium (He+) in the Earth's plasmasphere by imaging its emission at 30.4 nm. This instrument consisted of three separate camera heads, each with a 28° field-of-view, with 0.6°resolution. We describe an improved imaging system that can simultaneously image a 40° field-of-view with 0.45° resolution utilizing only one compact camera head and detector. This improved imager also increases sensitivity over the heritage EUV imager by a factor of four due to improvements in optical coatings, detector technology, and a larger entrance aperture.

Davis, Michael W.; Gladstone, G. Randall; Goldstein, Jerry; Sandel, Bill R.; Greathouse, Thomas K.; Retherford, Kurt D.; Winters, Gregory S.

2013-09-01

368

The wide field imager Lyman-alpha search (WFILAS) for galaxies at redshift ~5.7. II. Survey design and sample analysis  

Microsoft Academic Search

Context: .Wide-field narrowband surveys are an efficient way of searching large volumes of high-redshift space for distant galaxies. Aims: .We describe the Wide Field Imager Lyman-Alpha Search (WFILAS) over 0.74 sq. degree for bright emission-line galaxies at z ˜ 5.7. Methods: .WFILAS uses deep images taken with the Wide Field Imager (WFI) on the ESO\\/MPI 2.2 m telescope in three

E. Westra; D. Heath Jones; C. E. Lidman; K. Meisenheimer; R. M. Athreya; C. Wolf; T. Szeifert; E. Pompei; L. Vanzi

2006-01-01

369

The cryo-mechanical design of SCUBA2: a wide-field imager for the James Clerk Maxwell Telescope  

Microsoft Academic Search

The SCUBA-2 instrument is a new wide-field imager under development for the James Clerk Maxwell Telescope on Mauna Kea in Hawaii and due to be operational in 2006. The instrument has two separate focal planes and is designed to observe simultaneously at wavelengths of 450 and 850mum. The instrument cryostat will weigh around 2500kg and has a volume of approximately

David Gostick; Dave Montgomery; Bob Wall; Helen McGregor; Mark Cliffe; Adam Woodcraft; Fred Gannaway

2004-01-01

370

Survey-only optical strategies for cataloguing GEO and MEO objects in the future European Space Surveillance System  

NASA Astrophysics Data System (ADS)

In the framework of a potential European Space Situational Awareness System (ESSAS), we propose some optical strategies such that do not require tracking measurements for the orbit determination computation. We will analyse them in terms of coverage, timeliness and orbit determination accuracy by means of the AS4 simulator (developed by Deimos Space S.L.U.). Moreover observation campaigns have been performed from La Sagra Observatory in order to check the availability of those strategies. The operational capabilities will be compared within the simulated ones. This work includes a discussion about the improvements provided by "survey-only" strategies with respect of optical strategies that require tracking tasks for constructing a Space Debris catalogue. These strategies are used for defining different choices for the future European Optical Space Surveillance System in the framework of the ESA contract no. 22738/09/D/HK. In this work we also speak about these proposals.

Olmedo, Estrella; Sanchez-Ortiz, Noelia; Nomen, Jaime

371

New Mexico Fiber-Optic Link Marks Giant Leap Toward Future of Radio Astronomy  

NASA Astrophysics Data System (ADS)

SOCORRO, NM -- Scientists and engineers at the National Radio Astronomy Observatory (NRAO) have made a giant leap toward the future of radio astronomy by successfully utilizing the Very Large Array (VLA) radio telescope in conjunction with an antenna of the continent-wide Very Long Baseline Array (VLBA) using the longest fiber-optic data link ever demonstrated in radio astronomy. The 65-mile fiber link will allow scientists to use the two National Science Foundation (NSF) facilities together in real time, and is the first step toward expanding the VLA to include eight proposed new radio-telescope antennas throughout New Mexico. LEFT: Miller Goss, NRAO's director of VLA/VLBA Operations, unveils graphic showing success of the Pie Town-VLA fiber link. The project, funded by the NSF and Associated Universities, Inc. (AUI), which operates NRAO for the NSF, links the VLA and the VLBA antenna in Pie Town, NM, using a Western New Mexico Telephone Co. fiber-optic cable. The successful hookup was announced at a ceremony that also marked the 10th anniversary of NRAO's Operations Center in Socorro. "Linking the Pie Town antenna to the VLA quadruples the VLA's ability to make detailed images of astronomical objects," said Paul Vanden Bout, NRAO's Director. "This alone makes the link an advance for science, but its greater importance is that it clearly demonstrates the technology for improving the VLA's capabilities even more in the future." "Clearly, the big skies and wide open spaces in New Mexico create near perfect conditions for the incredible astronomical assets located in our state. This new fiber-optic link paves the way for multiplying the already breathtaking scientific capabilities of the VLA," Senator Pete Domenici (R-NM) said. The VLA is a system of 27 radio-telescope antennas distributed over the high desert west of Socorro, NM, in the shape of a giant "Y." Made famous in movies, commercials and numerous published photos, the VLA has been one of the most productive and versatile astronomical observatories in the world since its dedication in 1980. The VLBA is a continent-wide system of 10 radio telescopes distributed across the continental United States, Hawaii and St. Croix in the Caribbean. In both the VLA and VLBA, the cosmic radio waves received by each antenna are combined with those received from every other antenna in the system to produce images with extremely great resolving power, or ability to see fine detail. The more widely separated the antennas, the greater the resolving power. The greatest separation between antennas of the VLA is 20 miles; in the VLBA, 5,000 miles. If your eyes could see the same level of detail as the VLA, you could, at the distance from New York to Los Angeles, make out an object the size of a small car. With the resolving power of the VLBA, you could read the owner's manual. The VLBA can make images hundreds of times more detailed than those available from the Hubble Space Telescope. However, because of the way in which such multi-antenna radio telescopes, called interferometers, work, there is a gap between the levels of detail obtainable with the VLA and the VLBA. Linking the VLA to the VLBA Pie Town antenna is the first step toward filling in that gap and allowing astronomers to see all scales of structure -- small, medium-sized, and large -- in objects such as stars, galaxies and quasars. Additional antennas, distributed throughout New Mexico, would fully fill that gap. Adding the new antennas to the VLA "would provide the capability to image astronomical objects on all spatial scales, from the very largest to the very smallest. The combination of the VLA and VLBA then would be the only single instrument in astronomy covering such a range of spatial scales, and thus a tool of great and unique value to science," said Vanden Bout. LEFT: NRAO Director Paul Vanden Bout, left, speaks with U.S. Senator Pete Domenici, right, following the ceremony at the Array Operations Center in Socorro Dec. 15. Nobel Laureate Robert Wilson is in the ba

1998-12-01

372

WEAVE: the next generation wide-field spectroscopy facility for the William Herschel Telescope  

NASA Astrophysics Data System (ADS)

We present the preliminary design of the WEAVE next generation spectroscopy facility for the William Herschel Telescope (WHT), principally targeting optical ground-based follow up of upcoming ground-based (LOFAR) and spacebased (Gaia) surveys. WEAVE is a multi-object and multi-IFU facility utilizing a new 2 degree prime focus field of view at the WHT, with a buffered pick and place positioner system hosting 1000 multi-object (MOS) fibres or up to 30 integral field units for each observation. The fibres are fed to a single spectrograph, with a pair of 8k(spectral) x 6k (spatial) pixel cameras, located within the WHT GHRIL enclosure on the telescope Nasmyth platform, supporting observations at R~5000 over the full 370-1000nm wavelength range in a single exposure, or a high resolution mode with limited coverage in each arm at R~20000.

Dalton, Gavin; Trager, Scott C.; Abrams, Don Carlos; Carter, David; Bonifacio, Piercarlo; Aguerri, J. Alfonso L.; MacIntosh, Mike; Evans, Chris; Lewis, Ian; Navarro, Ramon; Agocs, Tibor; Dee, Kevin; Rousset, Sophie; Tosh, Ian; Middleton, Kevin; Pragt, Johannes; Terrett, David; Brock, Matthew; Benn, Chris; Verheijen, Marc; Cano Infantes, Diego; Bevil, Craige; Steele, Iain; Mottram, Chris; Bates, Stuart; Gribbin, Francis J.; Rey, Jürg; Rodriguez, Luis Fernando; Delgado, Jose Miguel; Guinouard, Isabelle; Walton, Nic; Irwin, Michael J.; Jagourel, Pascal; Stuik, Remko; Gerlofsma, Gerrit; Roelfsma, Ronald; Skillen, Ian; Ridings, Andy; Balcells, Marc; Daban, Jean-Baptiste; Gouvret, Carole; Venema, Lars; Girard, Paul

2012-09-01

373

Advanced wide-field broad-passband refracting field correctors for large telescopes  

NASA Technical Reports Server (NTRS)

Design objectives, constraints, and optical data are presented for specific corrector designs under consideration for several large telescope projects. These include a preliminary 30-arcmin prime focus (f/2.0) refracting field corrector system for the University of California Ten-Meter Telescope (UC TMT); a compact 40-arcmin internal Cassegrain (f/1.75 hyperbola to f/5.0) broad-passband (3300 A to 1.0 micron) corrector suitable for imaging and multi-object spectroscopy at the UC TMT; three 60-arcmin Cassegrain correctors for 300-inch f/1.8 and f/2.0 parabolic primary mirrors suitable for a Fifteen-Meter NNTT/MMT; and a 300-inch 40-arcmin external Cassegrain (f/1.0 parabola to f/4.0) broad-passband (3300 A to 1.0 micron) corrector with ADC.

Epps, H. W.; Angel, J. R. P.; Anderson, E.

1984-01-01

374

THE HUBBLE WIDE FIELD CAMERA 3 TEST OF SURFACES IN THE OUTER SOLAR SYSTEM: THE COMPOSITIONAL CLASSES OF THE KUIPER BELT  

SciTech Connect

We present the first results of the Hubble Wide Field Camera 3 Test of Surfaces in the Outer Solar System. The purpose of this survey was to measure the surface properties of a large number of Kuiper Belt objects and attempt to infer compositional and dynamical correlations. We find that the Centaurs and the low-perihelion scattered disk and resonant objects exhibit virtually identical bifurcated optical color distributions and make up two well-defined groups of objects. Both groups have highly correlated optical and NIR colors that are well described by a pair of two-component mixture models that have different red components but share a common neutral component. The small, H{sub 606} {approx}> 5.6 high-perihelion excited objects are entirely consistent with being drawn from the two branches of the mixing model, suggesting that the color bifurcation of the Centaurs is apparent in all small excited objects. On the other hand, objects larger than H{sub 606} {approx} 5.6 are not consistent with the mixing model, suggesting some evolutionary process avoided by the smaller objects. The existence of a bifurcation amongst all excited populations argues that the two separate classes of object existed in the primordial disk before the excited Kuiper Belt was populated. The cold classical objects exhibit a different type of surface that has colors that are consistent with being drawn from the red branch of the mixing model, but with much higher albedos.

Fraser, Wesley C.; Brown, Michael E., E-mail: fraserw@gps.caltech.edu [Division of Geological and Planetary Sciences, California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125 (United States)

2012-04-10

375

THE INFRARED EYE OF THE WIDE-FIELD CAMERA 3 ON THE HUBBLE SPACE TELESCOPE REVEALS MULTIPLE MAIN SEQUENCES OF VERY LOW MASS STARS IN NGC 2808  

SciTech Connect

We use images taken with the infrared channel of the Wide Field Camera 3 on the Hubble Space Telescope to study the multiple main sequences (MSs) of NGC 2808. Below the turnoff, the red, the middle, and the blue MS, previously detected from visual-band photometry, are visible over an interval of about 3.5 F160W magnitudes. The three MSs merge together at the level of the MS bend. At fainter magnitudes, the MS again splits into two components containing {approx}65% and {approx}35% of stars, with the most-populated MS being the bluest one. Theoretical isochrones suggest that the latter is connected to the red MS discovered in the optical color-magnitude diagram (CMD) and hence corresponds to the first stellar generation, having primordial helium and enhanced carbon and oxygen abundances. The less-populated MS in the faint part of the near-IR CMD is helium-rich and poor in carbon and oxygen, and it can be associated with the middle and the blue MS of the optical CMD. The finding that the photometric signature of abundance anti-correlation is also present in fully convective MS stars reinforces the inference that they have a primordial origin.

Milone, A. P.; Aparicio, A.; Monelli, M., E-mail: milone@iac.es, E-mail: aparicio@iac.es, E-mail: monelli@iac.es [Instituto de Astrofisica de Canarias, E-38200 La Laguna, Tenerife, Canary Islands (Spain); and others

2012-08-01

376

Installing the Future. Fiber Optics Program Readies Students for Lucrative Jobs.  

ERIC Educational Resources Information Center

A fiber optics program at Somerset County Technical Institute (SCTI) prepares college students and trades workers for telecommunication's new wave of installation. The program was born of a partnership among an electricians' union, AT&T, and SCTI to meet the expected need for fiber optic technicians. (JOW)

Serrano, Kenneth M.

1995-01-01

377

Thermostructural Analysis of the SOFIA Fine Field and Wide Field Imagers Subjected to Convective Thermal Shock  

NASA Technical Reports Server (NTRS)

The Stratospheric Observatory For Infrared Astronomy (SOFIA) is a highly modified Boeing 747-SP with a 17- ton infrared telescope installed in the aft portion of the aircraft. Unlike ground- and space-based platforms, SOFIA can deploy to make observations anytime, anywhere, in the world. The originally designed aircraft configuration included a ground pre-cool system, however, due to various factors in the history of the project, that system was not installed. This lack of ground pre-cooling was the source of the concern about whether or not the imagers would be exposed to a potentially unsafe thermostructural environment. This concern was in addition to the already-existing concern of some project members that the air temperature rate of change during flight (both at the same altitude as well as ascent or descent) could cause the imagers to be exposed to an unsafe thermostructural environment. Four optical components were identified as the components of concern: two of higher concern (one in each imager), and two of lower concern (one in each imager). The analysis effort began by analyzing one component, after which the analyses for the other components was deemed unnecessary. The purpose of this report is to document these findings as well as lessons learned from the effort.

Kostyk, Christopher B.

2012-01-01

378

Wide field imaging of solar system objects with an 8192 x 8192 CCD mosaic  

NASA Technical Reports Server (NTRS)

As part of this program, we successfully completed the construction of the world's largest CCD camera, an 8192 x 8192 CCD mosaic. The system employs 8 2K x 4K 3-edge buttable CCDs arranged in a 2 x 4 chip mosaic. The focal plane has small gaps (less than 1 mm) between mosaic elements and measures over 120 mm x 120 mm. The initial set of frontside illuminated CCDs were developed with Loral-Fairchild in a custom foundry run. The initial lots yielded of order 20 to 25 functional devices, of which we selected the best eight for inclusion for the camera. We have designed a custom 3-edge-buttable package that ensures the CCD dies are mounted flat to plus or minus 10 microns over the entire area of the mosaic. The mosaic camera system consists of eight separate readout signal chains controlled by two independent DSP microcontrollers. These are in turn interfaced to a Sun Sparc-10 workstation through two high speed fiber optic interfaces. The system saw first-light on the Canada-France-Hawaii Telescope on Mauna Kea in March 1995. First-light on the University of Hawaii 2.2-M Telescope on Mauna Kea was in July 1995. Both runs were quite successful. A sample of some of the early science from the first light run is reported in the publication, 'Observations of Weak Lensing in Clusters with an 8192 x 8192 CCD Mosaic Camera'.

Hall, Donald N. B.

1995-01-01

379

Design of a Multicast Optical Packet Switch Based on Fiber Bragg Grating Technology for Future Networks  

NASA Astrophysics Data System (ADS)

In this paper, a non-blocking multicast optical packet switch based on fiber Bragg grating technology with optical output buffers is proposed. Only the header of optical packets is converted to electronic signals to control the fiber Bragg grating array of input ports and the packet payloads should be transparently destined to their output ports so that the proposed switch can reduce electronic interfaces as well as the bit rate. The modulation and the format of packet payloads may be non-standard where packet payloads could also include different wavelengths for increasing the volume of traffic. The advantage is obvious: the proposed switch could transport various types of traffic. An easily implemented architecture which can provide multicast services is also presented. An optical output buffer is designed to queue the packets if more than one incoming packet should reach to the same destination output port or including any waiting packets in optical output buffer that will be sent to the output port at a time slot. For preserving service-packet sequencing and fairness of routing sequence, a priority scheme and a round-robin algorithm are adopted at the optical output buffer. The fiber Bragg grating arrays for both input ports and output ports are designed for routing incoming packets using optical code division multiple access technology.

Cheng, Yuh-Jiuh; Yeh, Tzuoh-Chyau; Cheng, Shyr-Yuan

2011-09-01

380

Looking for Speed!! Go Optical Ultra-Fast Photonic Logic Gates for the Future Optical Communication and Computing  

NASA Technical Reports Server (NTRS)

Recently, we developed two ultra-fast all-optical switches in the nanosecond and picosecond regimes. The picosecond switch is made of a polydiacetylene thin film coated on the interior wall of a hollow capillary of approximately 50 micron diameter by a photo-polymerization process. In the setup a picosecond Nd:YAG laser at 10 Hz and at 532 nm with a pulse duration of approximately 40 ps was sent collinearly along a cw He-Ne laser beam and both were waveguided through the hollow capillary. The setup functioned as an Exclusive OR gate. On the other hand, the material used in the nanosecond switch is a phthalocyanine thin film, deposited on a glass substrate by a vapor deposition technique. In the setup a nanosecond, 10 Hz, Nd:YAG laser of 8 ns pulse duration was sent collinearly along a cw He-Ne laser beam and both were wave-guided through the phthalocyanine thin film. The setup in this case functioned as an all-optical AND logic gate. The characteristic table of the ExOR gate in polydiacetylene film was attributed to an excited state absorption process, while that of the AND gate was attributed to a saturation process of the first excited state. Both mechanisms were thoroughly investigated theoretically and found to agree remarkably well with the experimental results. An all-optical inverter gate has been designed but has not yet been demonstrated. The combination of all these three gates form the foundation for building all the necessary gates needed to build a prototype of an all-optical system.

Abdeldayem, Hossin; Frazier, Donald O.; Penn, Benjamin; Paley, Mark S.

2003-01-01

381

X-RAY GROUPS OF GALAXIES IN THE AEGIS DEEP AND WIDE FIELDS  

SciTech Connect

We present the results of a search for extended X-ray sources and their corresponding galaxy groups from 800 ks Chandra coverage of the All-wavelength Extended Groth Strip International Survey (AEGIS). This yields one of the largest X-ray-selected galaxy group catalogs from a blind survey to date. The red-sequence technique and spectroscopic redshifts allow us to identify 100% of reliable sources, leading to a catalog of 52 galaxy groups. These groups span the redshift range z {approx} 0.066-1.544 and virial mass range M{sub 200} {approx} 1.34 Multiplication-Sign 10{sup 13}-1.33 Multiplication-Sign 10{sup 14} M{sub Sun }. For the 49 extended sources that lie within DEEP2 and DEEP3 Galaxy Redshift Survey coverage, we identify spectroscopic counterparts and determine velocity dispersions. We select member galaxies by applying different cuts along the line of sight or in projected spatial coordinates. A constant cut along the line of sight can cause a large scatter in scaling relations in low-mass or high-mass systems depending on the size of the cut. A velocity-dispersion-based virial radius can cause a larger overestimation of velocity dispersion in comparison to an X-ray-based virial radius for low-mass systems. There is no significant difference between these two radial cuts for more massive systems. Independent of radial cut, an overestimation of velocity dispersion can be created in the case of the existence of significant substructure and compactness in X-ray emission, which mostly occur in low-mass systems. We also present a comparison between X-ray galaxy groups and optical galaxy groups detected using the Voronoi-Delaunay method for DEEP2 data in this field.

Erfanianfar, G.; Lerchster, M.; Nandra, K.; Connelly, J. L.; Mirkazemi, M. [Max Planck-Institute for Extraterrestrial Physics, P.O. Box 1312, Giessenbachstr. 1., D-85741 Garching (Germany); Finoguenov, A. [Department of Physics, University of Helsinki, Gustaf Haellstroemin katu 2a, FI-00014 Helsinki (Finland); Tanaka, M. [Institute for the Physics and Mathematics of the Universe, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa-shi, Chiba 277-8583 (Japan); Laird, E. [Astrophysics Group, Imperial College London, Blackett Laboratory, Prince Consort Road, London SW7 2AZ (United Kingdom); Bielby, R. [Department of Physics, Durham University, South Road, Durham DH1 3LE (United Kingdom); Faber, S. M.; Kocevski, D.; Jeltema, T. [UCO/Lick Observatories, Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Cooper, M. [Center for Galaxy Evolution, Department of Physics and Astronomy, University of California, Irvine, 4129 Frederick Reines Hall, Irvine, CA 92697 (United States); Newman, J. A. [Department of Physics and Astronomy, University of Pittsburgh, 401-C Allen Hall, 3941 O'Hara Street, Pittsburgh, PA 15260 (United States); Coil, A. L. [Center for Astrophysics and Space Sciences, University of California, San Diego, 9500 Gilman Drive, MC 0424, San Diego, CA 92093 (United States); Brimioulle, F. [University Observatory Munich, Ludwigs-Maximilians University Munich, Scheinerstr. 1, D-81679 Munich (Germany); Davis, M. [Department of Astronomy, University of California, Berkeley, Berkeley, CA 94720 (United States); McCracken, H. J. [Institut d'Astrophysique de Paris, UMR 7095 CNRS, Universite Pierre et Marie Curie, 98 bis boulevard Arago, F-75014 Paris (France); Willmer, C. [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Gerke, B., E-mail: erfanian@mpe.mpg.de [Lawrence Berkeley National Laboratory, 1 Cyclotron Road MS 90R4000, Berkeley, CA 94720 (United States); and others

2013-03-10

382

X-Ray Groups of Galaxies in the AEGIS Deep and Wide Fields  

NASA Astrophysics Data System (ADS)

We present the results of a search for extended X-ray sources and their corresponding galaxy groups from 800 ks Chandra coverage of the All-wavelength Extended Groth Strip International Survey (AEGIS). This yields one of the largest X-ray-selected galaxy group catalogs from a blind survey to date. The red-sequence technique and spectroscopic redshifts allow us to identify 100% of reliable sources, leading to a catalog of 52 galaxy groups. These groups span the redshift range z ~ 0.066-1.544 and virial mass range M 200 ~ 1.34 × 1013-1.33 × 1014 M ?. For the 49 extended sources that lie within DEEP2 and DEEP3 Galaxy Redshift Survey coverage, we identify spectroscopic counterparts and determine velocity dispersions. We select member galaxies by applying different cuts along the line of sight or in projected spatial coordinates. A constant cut along the line of sight can cause a large scatter in scaling relations in low-mass or high-mass systems depending on the size of the cut. A velocity-dispersion-based virial radius can cause a larger overestimation of velocity dispersion in comparison to an X-ray-based virial radius for low-mass systems. There is no significant difference between these two radial cuts for more massive systems. Independent of radial cut, an overestimation of velocity dispersion can be created in the case of the existence of significant substructure and compactness in X-ray emission, which mostly occur in low-mass systems. We also present a comparison between X-ray galaxy groups and optical galaxy groups detected using the Voronoi-Delaunay method for DEEP2 data in this field.

Erfanianfar, G.; Finoguenov, A.; Tanaka, M.; Lerchster, M.; Nandra, K.; Laird, E.; Connelly, J. L.; Bielby, R.; Mirkazemi, M.; Faber, S. M.; Kocevski, D.; Cooper, M.; Newman, J. A.; Jeltema, T.; Coil, A. L.; Brimioulle, F.; Davis, M.; McCracken, H. J.; Willmer, C.; Gerke, B.; Cappelluti, N.; Gwyn, S.

2013-03-01

383

High-resolution wide-field imaging of perfused capillaries without the use of contrast agent  

PubMed Central

Purpose: Assessment of capillary abnormalities facilitates early diagnosis, treatment, and follow-up of common retinal pathologies. Injected contrast agents like fluorescein are widely used to image retinal capillaries, but this highly effective procedure has a few disadvantages, such as untoward side effects, inconvenience of injection, and brevity of the time window for clear visualization. The retinal function imager (RFI) is a tool for monitoring retinal functions, such as blood velocity and oximetry, based on intrinsic signals. Here we describe the clinical use of hemoglobin in red blood cells (RBCs) as an intrinsic motion-contrast agent in the generation of detailed noninvasive capillary-perfusion maps (nCPMs). Patients and methods: Multiple series of nCPM images were acquired from 130 patients with diabetic retinopathy, vein occlusion, central serous retinopathy, age-related macular degeneration, or metabolic syndrome, as well as from 37 healthy subjects. After registration, pixel value distribution parameters were analyzed to locate RBC motion. Results: The RFI yielded nCPMs demonstrating microvascular morphology including capillaries in exquisite detail. Maps from the same subject were highly reproducible in repeated measurements, in as much detail and often better than that revealed by the very best fluorescein angiography. In patients, neovascularization and capillary nonperfusion areas were clearly observed. Foveal avascular zones (FAZ) were sharply delineated and were larger in patients with diabetic retinopathy than in controls (FAZ diameter: 641.5 ± 82.3 versus 463.7 ± 105 ?m; P < 0.001). Also visible were abnormal vascular patterns, such as shunts and vascular loops. Conclusion: Optical imaging of retinal capillaries in human patients based on motion contrast is noninvasive, comfortable, safe, and can be repeated as often as required for early diagnosis, treatment guidance, and follow up of retinal disease progression. PMID:21887088

Nelson, Darin A; Burgansky-Eliash, Zvia; Barash, Hila; Loewenstein, Anat; Barak, Adiel; Bartov, Elisha; Rock, Tali; Grinvald, Amiram

2011-01-01

384

The Irkutsk Barium filter for narrow-band wide-field high-resolution solar images at the Dutch Open Telescope  

E-print Network

1 The Irkutsk Barium filter for narrow-band wide-field high-resolution solar images at the Dutch ABSTRACT A wide-field birefringent filter for the barium II line at 455.4nm is developed in Irkutsk. The Barium line is excellent for Doppler-shift measurements because of low thermal line-broadening and steep

Rutten, Rob

385

Looking a gift horse in the mouth: Evaluation of wide-field asteroid photometric surveys  

NASA Astrophysics Data System (ADS)

It has recently become possible to do a photometric survey of many asteroids at once, rather than observing single asteroids one (or occasionally a couple) at a time. We evaluate two such surveys. Dermawan et al. (Dermawan et al. [2011]. Publ. Astron. Soc. Jpn. 63, S555-S576) observed one night on the Subaru 8.2 m telescope, and Masiero et al. (Masiero, J., Jedicke, R., Durech, J., Gwen, S., Denneau, L., Larsen, J. [2009]. Icarus 204, 145-171) observed six nights over 2 weeks with the 3.6 m CFHT. Dermawan claimed 83 rotation periods from 127 detected asteroids; Masiero et al. claimed 218 rotation periods from 828 detections. Both teams claim a number of super-fast rotators (P < 2.2 h) among main belt asteroids larger than 250 m diameter, some up to several km in diameter. This would imply that the spin rate distribution of main belt asteroids differs from like-sized NEAs, that there are larger super-fast rotators (monolithic asteroids) in the main belt than among NEAs. Here we evaluate these survey results, applying the same criteria for reliability of results that we apply to all results listed in our Lightcurve Database (Warner, B.D., Harris, A.W., Pravec, P. [2009a]. Icarus 202, 134-146). In doing so, we assigned reliability estimates judged sufficient for inclusion in statistical studies for only 27 out of 83 (33%) periods claimed by Dermawan, and only 87 out of 218 (40%) periods reported by Masiero et al.; none of the super-fast rotators larger than about 250 m diameter claimed by either survey received a reliability rating judged sufficient for analysis. We find no reliable basis for the claim of different rotation properties between main belt and near-Earth asteroids. Our analysis presents a cautionary message for future surveys.

Harris, Alan W.; Pravec, Petr; Warner, Brian D.

2012-09-01

386

FT-IR spectroscopy technology, market evolution and future strategies of Bruker Optics Inc.  

E-print Network

This thesis explores the technology and market evolution of FT-IR spectroscopy over its nearly forty year history to aid in determining future product design and marketing strategies for an industry-leading firm, Bruker ...

Higdon, Thomas (Thomas Charles)

2010-01-01

387

A wide field-of-view imaging DOAS instrument for continuous trace gas mapping from aircraft  

NASA Astrophysics Data System (ADS)

For the purpose of trace gas measurements and pollution mapping, the Airborne imaging DOAS instrument for Measurements of Atmospheric Pollution (AirMAP) has been developed, characterised and successfully operated from aircraft. From the observations with the AirMAP instrument nitrogen dioxide (NO2) columns were retrieved. A major benefit of the pushbroom imaging instrument is the spatially continuous, gap-free measurement sequence independent of flight altitude, a valuable characteristic for mapping purposes. This is made possible by the use of a frame-transfer detector. With a wide-angle entrance objective, a broad field-of-view across track of around 48° is achieved, leading to a swath width of about the same size as the flight altitude. The use of fibre coupled light intake optics with sorted light fibres allows flexible positioning within the aircraft and retains the very good imaging capabilities. The measurements yield ground spatial resolutions below 100 m. From a maximum of 35 individual viewing directions (lines of sight, LOS) represented by 35 single fibres, the number of viewing directions is adapted to each situation by averaging according to signal-to-noise or spatial resolution requirements. Exploitation of all the viewing directions yields observations at 30 m spatial resolution, making the instrument a suitable tool for mapping trace gas point sources and small scale variability. For accurate spatial mapping the position and aircraft attitude are taken into account using the Attitude and Heading Reference System of the aircraft. A first demonstration mission using AirMAP was undertaken. In June 2011, AirMAP has been operated on the AWI Polar-5 aircraft in the framework of the AIRMETH2011 campaign. During a flight above a medium sized coal-fired power plant in North-West Germany, AirMAP clearly detects the emission plume downwind from the exhaust stack, with NO2 vertical columns around 2 × 1016 molecules cm-2 in the plume center. The emission estimates are consistent with reports in the pollutant transfer register. Strong spatial gradients and variability in NO2 amounts across and along flight direction are observed, and small-scale enhancements of NO2 above a motorway are detected. The present study reports on the experimental setup and characteristics of AirMAP, and the first measurements at high spatial resolution and wide spatial coverage are presented which meet the requirements for NO2 mapping to observe and account for the intrinsic variability of tropospheric NO2.

Schönhardt, A.; Altube, P.; Gerilowski, K.; Krautwurst, S.; Hartmann, J.; Meier, A. C.; Richter, A.; Burrows, J. P.

2014-04-01

388

McDonald Observatory Solar System Object Astrometry from Wide Field CCD Imaging  

NASA Astrophysics Data System (ADS)

In March 1994 our long standing program of astrometric observations of faint solar system objects at McDonald Observatory moved from a Cassegrain focus photographic plate camera on the 2.1 m telescope to an f/3 Prime Focus Corrector (PFC) and CCD system on the 0.76 m telescope. The PFC has an unvignetted 1.1 degree field of view, a flat focal surface with 0.01% distortion, and a spectral band width from 300 nm to 1100 nm. The present detector is a MetaChrome II-coated, Loral-Fairchild 2048x2048 CCD that covers a 46 arcmin by 46 arcmin area with 1.35 arcsec pixels. This instrument is capable of reaching R=21.5 with 3-sigma significance on stellar objects, in single 15 minute integrations. Optical, mechanical, and electronic improvements, now underway, will produce almost a 1 magnitude improvement in sensitivity and will increase data accuracy and precision. The HST Guide Star Selection System Catalog Version 1.1 is used as the astrometric reference catalog. We are working with other groups to improve the astrometric accuracy of results based on this catalog. Our observing program now concentrates on NASA asteroid and comet mission support (e.g. 433 Eros, 253 Mathilde, and 1620 Geographos), near-Earth objects, asteroids in peculiar regions of the main belt (e.g. the 3:1 resonance), and the natural satellites of the outer planets. We observe approximately three nights per month. A cloudless night results in some 75 exposures of 50 or more different objects. Minor planet and comet observations are reduced, measured, and reported to the Minor Planet Center within one week. Natural satellite results are segregated by primary and appear in the standard literature on an opposition basis. To date (10/26/95), we have obtained 722 observations of minor planets, 25 of comets, and 480 of natural satellites with the PFC/0.76 m telescope combination. The 1-sigma accuracy of the derived positions is approximately 0.5 arcseconds.

Whipple, A. L.; Shelus, P. J.; Whited, R. W.; Cochran, A. L.; MacQueen, P. J.; Benedict, G. F.

1995-12-01

389

Lensfree Fluorescent On-Chip Imaging of Transgenic Caenorhabditis elegans Over an Ultra-Wide Field-of-View  

PubMed Central

We demonstrate lensfree on-chip fluorescent imaging of transgenic Caenorhabditis elegans (C. elegans) over an ultra-wide field-of-view (FOV) of e.g., >2–8 cm2 with a spatial resolution of ?10µm. This is the first time that a lensfree on-chip platform has successfully imaged fluorescent C. elegans samples. In our wide-field lensfree imaging platform, the transgenic samples are excited using a prism interface from the side, where the pump light is rejected through total internal reflection occurring at the bottom facet of the substrate. The emitted fluorescent signal from C. elegans samples is then recorded on a large area opto-electronic sensor-array over an FOV of e.g., >2–8 cm2, without the use of any lenses, thin-film interference filters or mechanical scanners. Because fluorescent emission rapidly diverges, such lensfree fluorescent images recorded on a chip look blurred due to broad point-spread-function of our platform. To combat this resolution challenge, we use a compressive sampling algorithm to uniquely decode the recorded lensfree fluorescent patterns into higher resolution images, demonstrating ?10 µm resolution. We tested the efficacy of this compressive decoding approach with different types of opto-electronic sensors to achieve a similar resolution level, independent of the imaging chip. We further demonstrate that this wide FOV lensfree fluorescent imaging platform can also perform sequential bright-field imaging of the same samples using partially-coherent lensfree digital in-line holography that is coupled from the top facet of the same prism used in fluorescent excitation. This unique combination permits ultra-wide field dual-mode imaging of C. elegans on a chip which could especially provide a useful tool for high-throughput screening applications in biomedical research. PMID:21253611

Ozcan, Aydogan

2011-01-01

390

Paving the way for a future underwater omni-directional wireless optical communication systems  

Microsoft Academic Search

To lay down the foundation for an underwater omni-directional optical communication system for tele-operation, we tested a point-to-point optical communication system, using laser-emitting diodes (LEDs). The LEDs used in the test emitted light in the green and blue light spectrum and were tested in a pool and in a tank filled with lake water. The primary objective of these tests

Greg Baiden; Yassiah Bissiri; Andrew Masoti

2009-01-01

391

High-resolution corneal topography and tomography of fish eye using wide-field white light interference microscopy  

NASA Astrophysics Data System (ADS)

Topography and tomography of fish cornea is reconstructed using high resolution white light interference microscopy. White light interferograms at different depths were recorded by moving the object axially. For each depth position, five phase shifted interferograms were recorded and analyzed. From the reconstructed phase maps, the corneal topography and hence the refractive index was determined and from amplitude images the cross-sectional image of fish cornea was reconstructed. In the present method, we utilize a nearly common-path interference microscope and wide field illumination and hence do not require any mechanical B-scan. Therefore, the phase stability of the recorded data is improved.

Srivastava, Vishal; Nandy, Sreyankar; Singh Mehta, Dalip

2013-04-01

392

ISS-Lobster: A Proposed Wide-Field X-Ray Telescope on the International Space Station  

NASA Technical Reports Server (NTRS)

The Lobster wide-field imaging telescope combines simultaneous high FOV, high sensitivity and good position resolution. These characteristics can open the field of X-Ray time domain astronomy, which will study many interesting transient sources, including tidal disruptions of stars, supernova shock breakouts, and high redshift gamma-ray bursts. Also important will be its use for the X-ray follow-up of gravitational wave detections. I will describe our present effort to propose the Lobster concept for deployment on the International Space Station through a NASA Mission of Opportunity this fall.

Camp, Jordan

2012-01-01

393

Impacts on the Hubble Space Telescope Wide Field and Planetary Camera 2: Experimental Simulation of Micrometeoroid Capture  

NASA Technical Reports Server (NTRS)

Hypervelocity impact features have been recognized on painted surfaces returned from the Hubble Space Telescope (HST). Here we describe experiments that help us to understand their creation, and the preservation of micrometeoroid (MM) remnants. We simulated capture of silicate and sulfide minerals on the Zinc orthotitanate (ZOT) paint and Al alloy plate of the Wide Field and Planetary Camera 2 (WFPC2) radiator, which was returned from HST after 16 years in low Earth orbit (LEO). Our results also allow us to validate analytical methods for identification of MM (and orbital debris) impacts in LEO.

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

2014-01-01

394

New in-flight calibration adjustment of the Nimbus 6 and 7 earth radiation budget wide field of view radiometers  

NASA Technical Reports Server (NTRS)

In-flight calibration adjustments are developed to process data obtained from the wide-field-of-view channels of Nimbus-6 and Nimbus-7 after the failure of the Nimbus-7 longwave scanner on June 22, 1980. The sensor characteristics are investigated; the satellite environment is examined in detail; and algorithms are constructed to correct for long-term sensor-response changes, on/off-cycle thermal transients, and filter-dome absorption of longwave radiation. Data and results are presented in graphs and tables, including comparisons of the old and new algorithms.

Kyle, H. L.; House, F. B.; Ardanuy, P. E.; Jacobowitz, H.; Maschhoff, R. H.; Hickey, J. R.

1984-01-01

395

Fractionated Wide-Field Radiation Therapy Followed by Fractionated Local-Field Irradiation for Treating Widespread Painful Bone Metastasis  

SciTech Connect

Purpose: Wide-field radiation therapy (WFRT) is an effective treatment for widespread bone metastasis. We evaluated local-field irradiation (LFI) after fractionated WFRT (f-WFRT) for treating the patients with multiple painful bone lesions. Methods and Materials: From 1998 to 2007, 32 patients with multiple bone metastases were treated with fractionated LFI (f-LFI) after f-WFRT. All patients initially received 15 Gy in 5 fractions to a wide field, followed by LFI (9-15 Gy in 3 Gy fractions). Response was assessed by evaluating the degree of pain relief using a visual analog scale before radiotherapy, after f-WFRT, and after f-LFI. Results: Fractionated LFI following f-WFRT yielded an overall relief rate of 93.8% and a complete relief rate of 43.8%. The rate of the appearance of new disease was 6.3% for the patients with complete relief, 20.5% for the patients with a partial relief, and 50% for the patients with no relief. Conclusion: Fractionated LFI after f-WFRT is a well-tolerated and effective treatment for multiple metastatic bone disease.

Ki, Yongkan [Department of Radiation Oncology, Medical Research Institute, Pusan National University Hospital, Pusan National University School of Medicine, Busan (Korea, Republic of); Kim, Wontaek, E-mail: rokwt@hanmail.ne [Department of Radiation Oncology, Medical Research Institute, Pusan National University Hospital, Pusan National University School of Medicine, Busan (Korea, Republic of); Nam, Jiho; Kim, Donghyun; Jeon, Hosang; Park, Dahl; Kim, Dongwon [Department of Radiation Oncology, Medical Research Institute, Pusan National University Hospital, Pusan National University School of Medicine, Busan (Korea, Republic of)

2011-01-01

396

Sub-diffusive scattering parameter maps recovered using wide-field high-frequency structured light imaging  

PubMed Central

This study investigates the hypothesis that structured light reflectance imaging with high spatial frequency patterns (fx) can be used to quantitatively map the anisotropic scattering phase function distribution (P(?s)) in turbid media. Monte Carlo simulations were used in part to establish a semi-empirical model of demodulated reflectance (Rd) in terms of dimensionless scattering (?s?fx?1) and ?, a metric of the first two moments of the P(?s) distribution. Experiments completed in tissue-simulating phantoms showed that simultaneous analysis of Rd spectra sampled at multiple fx in the frequency range [0.05-0.5] mm?1 allowed accurate estimation of both ?s?(?) in the relevant tissue range [0.4-1.8] mm?1, and ?(?) in the range [1.4-1.75]. Pilot measurements of a healthy volunteer exhibited ?-based contrast between scar tissue and surrounding normal skin, which was not as apparent in wide field diffuse imaging. These results represent the first wide-field maps to quantify sub-diffuse scattering parameters, which are sensitive to sub-microscopic tissue structures and composition, and therefore, offer potential for fast diagnostic imaging of ultrastructure on a size scale that is relevant to surgical applications. PMID:25360357

Kanick, Stephen Chad; McClatchy, David M.; Krishnaswamy, Venkataramanan; Elliott, Jonathan T.; Paulsen, Keith D.; Pogue, Brian W.

2014-01-01

397

Spatial light modulator based active wide-field illumination for ex vivo and in vivo quantitative NIR FRET imaging  

PubMed Central

Fluorescence lifetime imaging is playing an increasing role in drug development by providing a sensitive method to monitor drug delivery and receptor-ligand interactions. However, the wide dynamic range of fluorescence intensity emitted by ex vivo and in vivo samples presents challenges in retrieving information over the whole subject accurately and quantitatively. To overcome this challenge, we developed an active wide-field illumination (AWFI) strategy based on a spatial light modulator that acquires optimal fluorescence signals by enhancing the dynamic range, signal to noise ratio, and estimation of lifetime-based parameters. We demonstrate the ability of AWFI to estimate Förster resonance energy transfer (FRET) donor fraction from dissected organs with high accuracy (standard deviation <6%) over the whole field of view, in contrast with the homogenous wide-field illumination. We further report its successful application to quantitative FRET imaging in a live mouse. AWFI allows improved detection of weak signals and enhanced quantitative accuracy in ex vivo and in vivo molecular fluorescence quantitative imaging. The technique allows for robust quantitative estimation of the bio-distribution of molecular probes and lifetime-based parameters over an extended imaging field exhibiting a large range of fluorescence intensities and at a high acquisition speed (less than 1 min). PMID:24688826

Zhao, Lingling; Abe, Ken; Rajoria, Shilpi; Pian, Qi; Barroso, Margarida; Intes, Xavier

2014-01-01

398

Harnessing Light: Capitalizing on Optical Science Trends and Challenges for Future Research. Final Technical Report  

SciTech Connect

The committee has during the earlier period finalized their work on the report, Optics and Photonics: Essential Technologies for Our Nation (2013) . The report did undergo review and initial editorial processing. The NRC released a pre-publication report on August 13, 2012. A final report is now available. The study director has been able to practice his skills in running a national academies committee. From a research perspective the grant has generated a report with recommendations to the government. The work itself is the meetings where the committee convened to hear presenters and to discuss the status of optics and photonics as well as writing the report.

Svedberg, Erik

2014-02-06

399

Noninvasive assessment of burn wound severity using optical technology: A review of current and future modalities  

PubMed Central

Clinical examination alone is not always sufficient to determine which burn wounds will heal spontaneously and which will require surgical intervention for optimal outcome. We present a review of optical modalities currently in clinical use and under development to assist burn surgeons in assessing burn wound severity, including conventional histology/ light microscopy, laser Doppler imaging, indocyanine green videoangiography, near-infrared spectroscopy and spectral imaging, in vivo capillary microscopy, orthogonal polarization spectral imaging, reflectance-mode confocal microscopy, laser speckle imaging, spatial frequency domain imaging, photoacoustic microscopy, and polarization-sensitive optical coherence tomography. PMID:21185123

Kaiser, Meghann; Yafi, Amr; Cinat, Marianne; Choi, Bernard; Durkin, Anthony J.

2011-01-01

400

MID-INFRARED SELECTION OF ACTIVE GALACTIC NUCLEI WITH THE WIDE-FIELD INFRARED SURVEY EXPLORER. I. CHARACTERIZING WISE-SELECTED ACTIVE GALACTIC NUCLEI IN COSMOS  

SciTech Connect

The Wide-field Infrared Survey Explorer (WISE) is an extremely capable and efficient black hole finder. We present a simple mid-infrared color criterion, W1 - W2 {>=} 0.8 (i.e., [3.4]-[4.6] {>=}0.8, Vega), which identifies 61.9 {+-} 5.4 active galactic nucleus (AGN) candidates per deg{sup 2} to a depth of W2 {approx} 15.0. This implies a much larger census of luminous AGNs than found by typical wide-area surveys, attributable to the fact that mid-infrared selection identifies both unobscured (type 1) and obscured (type 2) AGNs. Optical and soft X-ray surveys alone are highly biased toward only unobscured AGNs, while this simple WISE selection likely identifies even heavily obscured, Compton-thick AGNs. Using deep, public data in the COSMOS field, we explore the properties of WISE-selected AGN candidates. At the mid-infrared depth considered, 160 {mu}Jy at 4.6 {mu}m, this simple criterion identifies 78% of Spitzer mid-infrared AGN candidates according to the criteria of Stern et al. and the reliability is 95%. We explore the demographics, multiwavelength properties and redshift distribution of WISE-selected AGN candidates in the COSMOS field.

Stern, Daniel; Assef, Roberto J.; Eisenhardt, Peter [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Mail Stop 169-221, Pasadena, CA 91109 (United States); Benford, Dominic J. [NASA Goddard Space Flight Center, Code 665, Greenbelt, MD 20771 (United States); Blain, Andrew [Department of Physics and Astronomy, University of Leicester, LE1 7RH Leicester (United Kingdom); Cutri, Roc; Griffith, Roger L.; Jarrett, T. H.; Masci, Frank; Tsai, Chao-Wei; Yan, Lin [Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States); Dey, Arjun [National Optical Astronomical Observatory, 950 N. Cherry Ave., Tucson, AZ 85719 (United States); Lake, Sean; Petty, Sara; Wright, E. L. [Physics and Astronomy Department, University of California, Los Angeles, CA 90095 (United States); Stanford, S. A. [Department of Physics, University of California, One Shields Avenue, Davis, CA 95616 (United States); Harrison, Fiona; Madsen, Kristin, E-mail: daniel.k.stern@jpl.nasa.gov [Space Radiation Laboratory, California Institute of Technology, Pasadena, CA 91125 (United States)

2012-07-01

401

The Wide-Field X and Gamma-Ray Telescope ECLAIRs aboard the Gamma-Ray Burst Multi-Wavelength Space Mission SVOM  

SciTech Connect

The X and Gamma-ray telescope ECLAIRs is foreseen to be launched on a low Earth orbit (h = 630 km, i = 30 deg.) aboard the SVOM satellite (Space-based multi-band astronomical Variable Objects Monitor), a French-Chinese mission with Italian contribution. Observations are expected to start in 2013 (Wei, J., these proceedings). It has been designed to detect and localize Gamma-Ray Bursts (GRBs) or persistent sources of the sky, thanks to its wide field of view ({approx_equal}2 sr) and its remarkable sensitivity in the 4-250 keV energy range, with enhanced imaging sensitivity in the 4-70 keV energy band. These characteristics are well suited to detect highly redshifted GRBs, and consequently to provide fast and accurate triggers to other onboard or ground-based instruments able to follow-up the detected events in a very short time from the optical wavelength bands up to the few MeV Gamma-Ray domain.

Mandrou, P.; Pons, R.; Barret, D.; Amoros, C.; Lacombe, K. [CESR/CNRS/UPS, 9 Avenue Colonel Roche, BP 44346, 31028 Toulouse, Cedex 4 (France); Schanne, S.; Cordier, B.; Fesquet, M.; Limousin, O.; Sizun, P. [CEA Saclay, DSM/IRFU (former DAPNIA), 91191 Gif sur Yvette Cedex (France); Lebrun, F. [CEA Saclay, DSM/IRFU (former DAPNIA), 91191 Gif sur Yvette Cedex (France); APC, 10 Rue Alice Domont et Leonie Duquet, 75205 Paris Cedex 15 (France); Gonzalez, F.; Jouret, M. [CNES, CST, 18 Avenue Edouard Belin, 31401 Toulouse Cedex 9 (France)

2008-10-22

402

THE FLAT TRANSMISSION SPECTRUM OF THE SUPER-EARTH GJ1214b FROM WIDE FIELD CAMERA 3 ON THE HUBBLE SPACE TELESCOPE  

SciTech Connect

Capitalizing on the observational advantage offered by its tiny M dwarf host, we present Hubble Space Telescope/Wide Field Camera 3 (WFC3) grism measurements of the transmission spectrum of the super-Earth exoplanet GJ1214b. These are the first published WFC3 observations of a transiting exoplanet atmosphere. After correcting for a ramp-like instrumental systematic, we achieve nearly photon-limited precision in these observations, finding the transmission spectrum of GJ1214b to be flat between 1.1 and 1.7 {mu}m. Inconsistent with a cloud-free solar composition atmosphere at 8.2{sigma}, the measured achromatic transit depth most likely implies a large mean molecular weight for GJ1214b's outer envelope. A dense atmosphere rules out bulk compositions for GJ1214b that explain its large radius by the presence of a very low density gas layer surrounding the planet. High-altitude clouds can alternatively explain the flat transmission spectrum, but they would need to be optically thick up to 10 mbar or consist of particles with a range of sizes approaching 1 {mu}m in diameter.

Berta, Zachory K.; Charbonneau, David; Desert, Jean-Michel; Irwin, Jonathan [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Miller-Ricci Kempton, Eliza; Fortney, Jonathan J.; Nutzman, Philip [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); McCullough, Peter R. [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Burke, Christopher J. [SETI Institute/NASA Ames Research Center, M/S 244-30, Moffett Field, CA 94035 (United States); Homeier, Derek, E-mail: zberta@cfa.harvard.edu [Centre de Recherche Astrophysique de Lyon, UMR 5574, CNRS, Universite de Lyon, Ecole Normale Superieure de Lyon, F-69364 Lyon Cedex 07 (France)

2012-03-01

403

CEPHEID PERIOD-LUMINOSITY RELATIONS IN THE NEAR-INFRARED AND THE DISTANCE TO M31 FROM THE HUBBLE SPACE TELESCOPE WIDE FIELD CAMERA 3  

SciTech Connect

We present measurements of 68 classical Cepheids, most detected from the Canada-France-Hawaii Telescope POMME Survey, with periods from 10 to 78 days observed in the near-infrared by the Panchromatic Hubble Andromeda Treasury Program using the Wide Field Camera 3 (WFC3) on the Hubble Space Telescope (HST). The combination of HST's resolution and the use of near-infrared measurements provide a dramatic reduction in the dispersion of the period-luminosity relation over the present optical, ground-based data. Even using random phase magnitudes we measure a dispersion of just 0.17 mag, implying a dispersion of just 0.12 mag for mean magnitudes. The error in the mean for this relation is 1% in distance. Combined with similar observations of Cepheids in other hosts and independent distance determinations, we measure a distance to M31 of {mu}{sub 0} = 24.38 {+-} 0.06(statistical) {+-} 0.03(systematic), 752 {+-} 27 kpc, in good agreement with past measurements though with a better, 3% precision here. The result is also in good agreement with independent distance determinations from two detached eclipsing binaries allowing for an independent calibration of the Cepheid luminosities and a determination of the Hubble constant.

Riess, Adam G. [Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218 (United States); Fliri, Juergen; Valls-Gabaud, David, E-mail: ariess@stsci.edu, E-mail: jurgen.fliri@obspm.fr, E-mail: david.valls-gabaud@obspm.fr [LERMA, CNRS UMR 8112, Observatoire de Paris, 61 Avenue de l'Observatoire, F-75014 Paris (France)

2012-02-01

404

Noninvasive assessment of burn wound severity using optical technology: A review of current and future modalities  

E-print Network

Review Noninvasive assessment of burn wound severity using optical technology: A review of current b a Department of Surgery, Division of Trauma, Burns, Critical Care and Acute Care Surgery to determine which burn wounds will heal spontaneously and which will require surgical intervention for optimal

Choi, Bernard

405

In the (Not So) Distant Future: Fiber Optic Distance Learning at the University of Northern Iowa.  

ERIC Educational Resources Information Center

Currently every Area Education Agency, community college, and Regent University in Iowa is connected by a fiber optic system known as the Iowa Communications Network (ICN). Every semester, 7 to 13 college credit classes have been offered at the University of Northern Iowa (UNI) via the ICN since 1993. In the Spring of 1995 seven classes (six…

Bozik, Mary

406

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)

The Hubble Space Telescope (HST) is one of NASA s premier astronomical observatories. A unique design feature of the spacecraft is its capacity to be serviced and refurbished on-orbit. Repairs to the HST are made during events called Servicing Missions (SM). The SM consists of several phases that include: shuttle launch, ascent, rendezvous with HST, grapple, Extra Vehicular Activity (EVA) servicing, redeployment of the HST, shuttle entry and landing. The purpose of a SM is to upgrade the HST scientific capabilities and to repair or replace failed equipment. The benefit of the SM is to enhance the scientific capability of the HST and to extend its operational lifetime to a decade or more. Extra Vehicular Activity (EVA) days, the crew will replace the Wide Field Planetary Camera II (WFPCII) with the Wide Field Camera 3 (WFC3). The HST slot for these instruments is the "-V3 Radial Instrument" position. Servicing Mission 4 (SM-4) is currently scheduled for Spring 2005. During one of the five The WFC3 contains both Ultraviolet and Infrared detectors. Due to the differing thermal requirements for these items and their associated assemblies, the WFC3 contains several thermal subsystems within the instrument enclosure. One of these subsystems is the Variable Conductance Heat Pipe (VCHP) assembly. contains an integral constant conductance heat pipe (CCHP); a variable conductance heat pipe (VCHP); and a VCHP reservoir radiator (offset from the main WFC3 external radiator). The VCHP condenser utilizes the main WFC3 external radiator to reject its heat to space. The WFC3 VCHP assembly consists of the Optical Bench Cold Plate (OBCP), which The primary challenge for the VCHP assembly is to maintain the OBCP at -5 C +/- 2 C for various heat loads while subject to a 90-minute orbit cycling environment which ranges from 0 C to -143 C. Key components that provide active control include a 10 W heater system, the reservoir, and a proportional controller. This paper summarizes the overall thermal vacuum test program for the VCHP assembly. This includes performance during the 90-minute orbit cycling case, maximum capacity case, and cold system shut down case. The test was conducted in Building 7, Chamber #237 at the NASA/Goddard Space Flight Center. It lasted approximately fourteen days, from 5-28-02 to 6-10-02. Included in this paper is a comparison of the results with thermal model temperature predictions.

Cleveland, Paul E.; Buchko, Matthew T.; Stavely, Richard A.; Simpson, Alda (Technical Monitor)

2002-01-01

407

Assessing the future of diffuse optical imaging technologies for breast cancer management  

SciTech Connect

Diffuse optical imaging (DOI) is a noninvasive optical technique that employs near-infrared (NIR) light to quantitatively characterize the optical properties of thick tissues. Although NIR methods were first applied to breast transillumination (also called diaphanography) nearly 80 years ago, quantitative DOI methods employing time- or frequency-domain photon migration technologies have only recently been used for breast imaging (i.e., since the mid-1990s). In this review, the state of the art in DOI for breast cancer is outlined and a multi-institutional Network for Translational Research in Optical Imaging (NTROI) is described, which has been formed by the National Cancer Institute to advance diffuse optical spectroscopy and imaging (DOSI) for the purpose of improving breast cancer detection and clinical management. DOSI employs broadband technology both in near-infrared spectral and temporal signal domains in order to separate absorption from scattering and quantify uptake of multiple molecular probes based on absorption or fluorescence contrast. Additional dimensionality in the data is provided by integrating and co-registering the functional information of DOSI with x-ray mammography and magnetic resonance imaging (MRI), which provide structural information or vascular flow information, respectively. Factors affecting DOSI performance, such as intrinsic and extrinsic contrast mechanisms, quantitation of biochemical components, image formation/visualization, and multimodality co-registration are under investigation in the ongoing research NTROI sites. One of the goals is to develop standardized DOSI platforms that can be used as stand-alone devices or in conjunction with MRI, mammography, or ultrasound. This broad-based, multidisciplinary effort is expected to provide new insight regarding the origins of breast disease and practical approaches for addressing several key challenges in breast cancer, including: Detecting disease in mammographically dense tissue, distinguishing between malignant and benign lesions, and understanding the impact of neoadjuvant chemotherapies.

Tromberg, Bruce J.; Pogue, Brian W.; Paulsen, Keith D.; Yodh, Arjun G.; Boas, David A.; Cerussi, Albert E. [Beckman Laser Institute and Medical Clinic, University of California Irvine, Irvine, California 92612 (United States) and NCI Network for Translational Research in Optical Imaging, Beckman Laser Institute, Irvine, California 92612 (United States); Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755 (United States) and NCI Network for Translational Research in Optical Imaging, Beckman Laser Institute, Irvine, California 92612 (United States); Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6396 (United States) and NCI Network for Translational Research in Optical Imaging, Beckman Laser Institute, Irvine, California 92612 (United States); NMR Center, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02129 (United States) and NCI Network for Translational Research in Optical Imaging, Beckman Laser Institute, Irvine, California 92612 (United States); Beckman Laser Institute and Medical Clinic, University of California Irvine, Irvine, California 92612 (United States) and NCI Network for Translational Research in Optical Imaging, Beckman Laser Institute, Irvine, California 92612 (United States)

2008-06-15