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1

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

2

Adaptive wide-field optical tomography  

PubMed Central

Abstract. We describe a wide-field optical tomography technique, which allows the measurement-guided optimization of illumination patterns for enhanced reconstruction performances. The iterative optimization of the excitation pattern aims at reducing the dynamic range in photons transmitted through biological tissue. It increases the number of measurements collected with high photon counts resulting in a dataset with improved tomographic information. Herein, this imaging technique is applied to time-resolved fluorescence molecular tomography for preclinical studies. First, the merit of this approach is tested by in silico studies in a synthetic small animal model for typical illumination patterns. Second, the applicability of this approach in tomographic imaging is validated in vitro using a small animal phantom with two fluorescent capillaries occluded by a highly absorbing inclusion. The simulation study demonstrates an improvement of signal transmitted (?2 orders of magnitude) through the central portion of the small animal model for all patterns considered. A corresponding improvement in the signal at the emission wavelength by 1.6 orders of magnitude demonstrates the applicability of this technique for fluorescence molecular tomography. The successful discrimination and localization (?1??mm error) of the two objects with higher resolution using the optimized patterns compared with nonoptimized illumination establishes the improvement in reconstruction performance when using this technique. PMID:23475290

Venugopal, Vivek; Intes, Xavier

2013-01-01

3

Adaptive optics wide-field microscopy using direct wavefront sensing  

E-print Network

Adaptive optics wide-field microscopy using direct wavefront sensing Oscar Azucena,1, * Justin, Santa Cruz, 1156 High Street, Santa Cruz, California 95064, USA 3 Laboratory for Adaptive Optics at a different wavelength, enabling the structure of the sample to be resolved. © 2011 Optical Society of America

Sullivan, William T.

4

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

5

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

NASA Technical Reports Server (NTRS)

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

1979-01-01

6

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

NASA Astrophysics Data System (ADS)

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

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

2014-07-01

7

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

8

Manufacture Of A Three-Mirror Wide-Field Optical System  

NASA Astrophysics Data System (ADS)

An all-reflecting three-mirror infrared optical system has been built by Itek Optical Systems to demonstrate the feasibility of manufacturing such eccentric field designs. The device is a reduced field (1°) version of a three-mirror long wide-field design having a 15.24 cm aperture. Methods for fabricating off-axis aspheric mirrors and aligning eccentric component systems are presented. Results of interferometry to derive image performance characteristics are also given.

Egdall, Ira M.

1985-04-01

9

Wide Field Optical Camera for Search and Investigation of Fast Cosmic Transients  

SciTech Connect

The primary purpose of the fast wide field optical camera (WFOC) is to perform continuous, alert-independent observations of optical transients and variable astrophysical sources simultaneously with space-born wide field X- and {gamma}-ray telescopes. In particular the camera can detect possible optical precursors and early prompt emission from cosmic Gamma-Ray Bursts. The real-time source identification software generates alerts that also could be sent to global alert distribution networks such as the GCN. We estimate that in one year of continuous observation with the WFOC we will observe the following numbers of GRB error boxes simultaneously with space- borne telescopes: 1.6 (WXM/HETE-2), 0.5 (SPI/INTEGRAL), and 4 (BAT/SWIFT)

Pozanenko, A.; Loznikov, V. [IKI RAS, Moscow (Russian Federation); Beskin, G.; Karpov, S. [SAO RAS, Karachai-Cherkessia (Russian Federation); Bondar, S.; Ivanov, E. [Kosmoten Observatory, Karachai-Cherkessia (Russian Federation); Biryukov, A.; Zolotukhin, Y. [SAI MSU, Moscow (Russian Federation); Hurley, K. [UC Berkeley Space Sciences Laboratory (United States); Rumyantsev, V. [CrAO, Crimea (Ukraine)

2004-09-28

10

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

PubMed

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

2010-11-01

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

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

13

Optics integration of the OMM wide-field visible camera (Panoramix-II)  

NASA Astrophysics Data System (ADS)

The advent of wide-field imagers on large telescopes (Megacam at CFHT, Suprime-Cam at Subaru, and others) with degree-wide fields of view is largely motivated by a renewed interest in our own solar system, in the history of the Milky Way and its neighbors, and in the large-scale structure of the Universe. Smaller, university-based telescopes can of course also benefit from wide-field imagery. We present in this paper the design and first results of Panoramix-II, the new wide-field imager of the Mont Megantic Observatory (OMM). This instrument is conceptually a focal reducer designed to image and correct the F/8 cassegrain focal plane of the telescope onto a pair of 2KX4K EEV detectors. The camera is optimized for the SLOAN g' (410-550 nm), r' (550-690 nm), i' (690-850 nm) and z' (850-950 nm) wave bands. The sky will be imaged onto the focal plane at an image scale of 0.52 arcsecond per 13.5 ?m pixel. The design image quality is 1.00 arcsecond 50% diffraction encircled energy over the central 35 arcmin field and no images worse than 1.25 arcsecond over the 49 arcminute diameter camera field. The optical design distortion at the corners is less than 1%. The Panoramix-II camera has a filter wheel at the internal stop. Panoramix-II can also support the FaNTOmM photon-counting camera used in conjunction with a Fabry-Perot interferometer to provide spectrometric data.

Thibault, S.; Wang, M.; Côté, P.; Drissen, L.; Brière, É.

2006-06-01

14

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

15

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

NASA Astrophysics Data System (ADS)

We are conducting a feasibility study on a wide field of regard Multi-Object Adaptive Optics system for TMT (TMT-AGE:TMT-Analyzer for Galaxies in the Early universe). The wide FoR is crucial to effectively observe very high-redshift UV-bright galaxies at z>5, which have low surface number density. Simulations of an MOAO system show moderate AO correction can be achieved within 10 arcmin diameter FoR. We discuss overall system design of the wide FoR MOAO system considering the system constraint from the stroke of small-size deformable mirror.

Akiyama, Masayuki; Oya, S.; Ono, Y. H.; TMT-AGE Team

2014-07-01

16

Performance Modeling of a Wide Field Ground Layer Adaptive Optics System  

E-print Network

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 wavefront errors from the lowest altitude turbulence. GLAO concentrates more light from a point source in a smaller area on the science detector, but unlike traditional adaptive optics, images do not become diffraction-limited. Rather the GLAO point spread function (PSF) has the same functional form as a seeing-limited PSF, and can be characterized by familiar performance metrics such as Full-Width Half-Max (FWHM). The FWHM of a GLAO PSF is reduced by 0.1" or more for optical and near-infrared wavelengths over different atmospheric conditions. For the Cerro Pachon atmospheric model this correction is even greater when the image quality is worst, which effectively eliminates "bad-seeing" nights; the best seeing-limited image quality, available only 20% of the time, can be achieved 60 to 80% of the time with GLAO. This concentration of energy in the PSF will reduce required exposure times and improve the efficiency of an observatory up to 30 to 40%. These performance gains are relatively insensitive to a number of trades including the exact field of view of a wide field GLAO system, the conjugate altitude and actuator density of the deformable mirror, and the number and configuration of the guide stars.

D. Andersen; J. Stoesz; S. Morris; M. Lloyd-Hart; D. Crampton; T. Butterley; B. Ellerbroek; L. Jollissaint; N. M. Milton; R. Myers; K. Szeto; A. Tokovinin; J. -P. Veran; R. Wilson

2006-10-03

17

Catadioptric null test of ultra-deep concave aspheric lens in wide-field optical system.  

PubMed

To test the ultra-deep conic surface in wide-field optical systems, a catadioptric null test method is researched in this paper. Equations of infinite conjugate null test system are established and solved using optical path length. The numeric results of a self-aligning mirror's shapes are fitted by coefficients and validation is done in optical design software. The rms wavefront error is 0.0019? (?=632.8 nm) in the example fitted by five coefficients. Furthermore, by adjusting spherical aberration distributions, an all-spherical finite conjugate null test system is designed, whose rms wavefront error is 0.0309?. The test methods in this paper have been proven to be adaptive to many other similar ultra-deep surfaces, even with higher orders. PMID:23842273

Zhong, Xing; Jin, Guang

2013-07-01

18

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

NASA Technical Reports Server (NTRS)

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 of about 1 deg are resolved so that a comprehensive deep search is possible with a payload of 1/10 the linear dimensions of AXAF. By dropping the requirement for perfect on-axis imagery, searching within a suitably general class of telescope design, and optimizing a quantity directly related to the scientific requirement, it is shown that satisfactory designs do exist. The resulting telescope is shown to be no more difficult to fabricate than existing mirrors, and it can be nested.

Burrows, Christopher J.; Burg, Richard; Giacconi, Riccardo

1992-01-01

19

High-resolution wide-field imaging of retinal and choroidal blood perfusion with optical microangiography  

PubMed Central

We present high-resolution wide-field imaging of retinal and choroidal blood perfusion with optical microangiography (OMAG) technology. Based on spatial frequency analysis, OMAG is capable of visualizing the vascular perfusion map down to capillary-level resolution. An OMAG system operating at 840 nm is used with an A-scan rate of 27,000 Hz, axial resolution of 8 ?m, and sensitivity of 98 dB. To achieve wide-field imaging, we capture 16 optical coherence tomography (OCT) 3-D datasets in a sequential order, which together provide an area of ?7.4×7.4 mm2 at the posterior segment of the human eye. For each of these datasets, the bulk tissue motion artifacts are eliminated by applying a phase compensation method based on histogram estimation of bulk motion phases, while the displacements occurring between adjacent B-frames are compensated for by 2-D cross correlation between two adjacent OMAG flow images. The depth-resolved capability of OMAG imaging also provides volumetric information on the ocular circulations. Finally, we compare the clinical fluorescein angiography and indocyanine green angiography imaging results with the OMAG results of blood perfusion map within the retina and choroid, and show excellent agreement between these modalities. PMID:20459256

An, Lin; Subhush, Hrebesh M.; Wilson, David J.; Wang, Ruikang K.

2010-01-01

20

Current and Future Developments in Deep, Wide--field VLBI Continuum Surveys  

E-print Network

I review the current status of deep, wide-field VLBI continuum surveys. I also discuss anticipated short and long-term improvements in sensitivity (e.g. the eEVN), and the science these developments will enable.

M. A. Garrett

2002-05-27

21

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

NASA Technical Reports Server (NTRS)

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

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

2011-01-01

22

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

23

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

NASA Astrophysics Data System (ADS)

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

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

2006-01-01

24

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

NASA Technical Reports Server (NTRS)

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

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

2010-01-01

25

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

NASA Astrophysics Data System (ADS)

Small animal imaging plays a critical role in present day biomedical research by filling an important gap in the translation of research from the bench to the bedside. Optical techniques constitute an emerging imaging modality which have tremendous potential in preclinical applications. Optical imaging methods are capable of non-invasive assessment of the functional and molecular characteristics of biological tissue. The three-dimensional optical imaging technique, referred to as diffuse optical tomography, provides an approach for the whole-body imaging of small animal models and can provide volumetric maps of tissue functional parameters (e.g. blood volume, oxygen saturation etc.) and/or provide 3D localization and quantification of fluorescence-based molecular markers in vivo. However, the complex mathematical reconstruction problem associated with optical tomography and the cumbersome instrumental designs limits its adoption as a high-throughput quantitative whole-body imaging modality in current biomedical research. The development of new optical imaging paradigms is thus necessary for a wide-acceptance of this new technology. In this thesis, the design, development, characterization and optimization of a small animal optical tomography system is discussed. Specifically, the platform combines a highly sensitive time-resolved imaging paradigm with multi-spectral excitation capability and CCD-based detection to provide a system capable of generating spatially, spectrally and temporally dense measurement datasets. The acquisition of such data sets however can take long and translate to often unrealistic acquisition times when using the classical point source based excitation scheme. The novel approach in the design of this platform is the adoption of a wide-field excitation scheme which employs extended excitation sources and in the process allows an estimated ten-fold reduction in the acquisition time. The work described herein details the design of the imaging platform employing DLP-based excitation and time-gated intensified CCD detection and the optimal system operation parameters are determined. The feasibility this imaging approach and accuracy of the system in reconstructing functional parameters and fluorescence markers based on lifetime contrast is established through phantom studies. As a part of the system characterization, the effect of noise in time-resolved optical tomography is investigated and propagation of system noise in optical reconstructions is established. Furthermore, data processing and measurement calibration techniques aimed at reducing the effect of noise in reconstructions are defined. The optimization of excitation pattern selection is established through a novel measurement-guided iterative pattern correction scheme. This technique referred to as Adaptive Full-Field Optical Tomography was shown to improve reconstruction performances in murine models by reducing the dynamic range in photon flux measurements on the surface. Lastly, the application of the unique attributes of this platform to a biologically relevant imaging application, referred to as Forster Resonance Energy Transfer is described. The tomographic imaging of FRET interaction in vivo on a whole-body scale is achieved using the wide-field imaging approach based on lifetime contrast. This technique represents the first demonstration of tomographic FRET imaging in small animals and has significant potential in the development of optical imaging techniques in varied applications ranging from drug discovery to in vivo study of protein-protein interaction.

Venugopal, Vivek

26

Measuring galaxy [O ii] emission line doublet with future ground-based wide-field spectroscopic surveys  

NASA Astrophysics Data System (ADS)

The next generation of wide-field spectroscopic redshift surveys will map the large-scale galaxy distribution in the redshift range 0.7 ? z ? 2 to measure baryonic acoustic oscillations (BAO). The primary optical signature used in this redshift range comes from the [Oii] emission line doublet, which provides a unique redshift identification that can minimize confusion with other single emission lines. To derive the required spectrograph resolution for these redshift surveys, we simulate observations of the [Oii] (?? 3727, 3729) doublet for various instrument resolutions, and line velocities. We foresee two strategies for the choice of the resolution for future spectrographs for BAO surveys. For bright [Oii] emitter surveys ([Oii] flux ~30 × 10-17 erg cm-2 s-1 like SDSS-IV/eBOSS), a resolution of R ~ 3300 allows the separation of 90 percent of the doublets. The impact of the sky lines on the completeness in redshift is less than 6 percent. For faint [Oii] emitter surveys ([Oii] flux ~10 × 10-17 erg cm-2 s-1 like DESi), the detection improves continuously with resolution, so we recommend the highest possible resolution, the limit being given by the number of pixels (4k by 4k) on the detector and the number of spectroscopic channels (2 or 3).

Comparat, Johan; Kneib, Jean-Paul; Bacon, Roland; Mostek, Nick J.; Newman, Jeffrey A.; Schlegel, David J.; Yèche, Christophe

2013-11-01

27

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

28

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

29

Dual-conjugate adaptive optics for wide-field high-resolution retinal imaging.  

PubMed

We present analysis and preliminary laboratory testing of a real-time dual-conjugate adaptive optics (DCAO) instrument for ophthalmology that will enable wide-field high resolution imaging of the retina in vivo. The setup comprises five retinal guide stars (GS) and two deformable mirrors (DM), one conjugate to the pupil and one conjugate to a plane close to the retina. The DCAO instrument has a closed-loop wavefront sensing wavelength of 834 nm and an imaging wavelength of 575 nm. It incorporates an array of collimator lenses to spatially filter the light from all guide stars using one adjustable iris, and images the Hartmann patterns of multiple reference sources on a single detector. Zemax simulations were performed at 834 nm and 575 nm with the Navarro 99 and the Liou- Brennan eye models. Two correction alternatives were evaluated; conventional single conjugate AO (SCAO, using one GS and a pupil DM) and DCAO (using multiple GS and two DM). Zemax simulations at 575 nm based on the Navarro 99 eye model show that the diameter of the corrected field of view for diffraction-limited imaging (Strehl >or= 0.8) increases from 1.5 deg with SCAO to 6.5 deg using DCAO. The increase for the less stringent condition of a wavefront error of 1 rad or less (Strehl >or= 0.37) is from 3 deg with SCAO to approximately 7.4 deg using DCAO. Corresponding results for the Liou-Brennan eye model are 3.1 deg (SCAO) and 8.2 deg (DCAO) for Strehl >or= 0.8, and 4.8 deg (SCAO) and 9.6 deg (DCAO) for Strehl >or= 0.37. Potential gain in corrected field of view with DCAO is confirmed both by laboratory experiments on a model eye and by preliminary in vivo imaging of a human eye. PMID:19293873

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

2009-03-16

30

Innovations of wide-field optical-sectioning fluorescence microscopy: toward high-speed volumetric bio-imaging with simplicity  

NASA Astrophysics Data System (ADS)

Optical microscopy has become an indispensable tool for biological researches since its invention, mostly owing to its sub-cellular spatial resolutions, non-invasiveness, instrumental simplicity, and the intuitive observations it provides. Nonetheless, obtaining reliable, quantitative spatial information from conventional wide-field optical microscopy is not always intuitive as it appears to be. This is because in the acquired images of optical microscopy the information about out-of-focus regions is spatially blurred and mixed with in-focus information. In other words, conventional wide-field optical microscopy transforms the three-dimensional spatial information, or volumetric information about the objects into a two-dimensional form in each acquired image, and therefore distorts the spatial information about the object. Several fluorescence holography-based methods have demonstrated the ability to obtain three-dimensional information about the objects, but these methods generally rely on decomposing stereoscopic visualizations to extract volumetric information and are unable to resolve complex 3-dimensional structures such as a multi-layer sphere. The concept of optical-sectioning techniques, on the other hand, is to detect only two-dimensional information about an object at each acquisition. Specifically, each image obtained by optical-sectioning techniques contains mainly the information about an optically thin layer inside the object, as if only a thin histological section is being observed at a time. Using such a methodology, obtaining undistorted volumetric information about the object simply requires taking images of the object at sequential depths. Among existing methods of obtaining volumetric information, the practicability of optical sectioning has made it the most commonly used and most powerful one in biological science. However, when applied to imaging living biological systems, conventional single-point-scanning optical-sectioning techniques often result in certain degrees of photo-damages because of the high focal intensity at the scanning point. In order to overcome such an issue, several wide-field optical-sectioning techniques have been proposed and demonstrated, although not without introducing new limitations and compromises such as low signal-to-background ratios and reduced axial resolutions. As a result, single-point-scanning optical-sectioning techniques remain the most widely used instrumentations for volumetric imaging of living biological systems to date. In order to develop wide-field optical-sectioning techniques that has equivalent optical performance as single-point-scanning ones, this thesis first introduces the mechanisms and limitations of existing wide-field optical-sectioning techniques, and then brings in our innovations that aim to overcome these limitations. We demonstrate, theoretically and experimentally, that our proposed wide-field optical-sectioning techniques can achieve diffraction-limited optical sectioning, low out-of-focus excitation and high-frame-rate imaging in living biological systems. In addition to such imaging capabilities, our proposed techniques can be instrumentally simple and economic, and are straightforward for implementation on conventional wide-field microscopes. These advantages together show the potential of our innovations to be widely used for high-speed, volumetric fluorescence imaging of living biological systems.

Yu, Jiun-Yann

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

Design of all reflective zoom optical system of wide field of view with 3 mirrors  

NASA Astrophysics Data System (ADS)

All reflective zoom optical systems have advantages of no color aberration and lightweight which have a wide application prospects in space optical system. All reflective zoom optical systems, which have been designed, all use telephoto construction. And these systems have disadvantages of big obscuration and small field of view. So in order to satisfy of requests the wide spectrum and field of view of space optical system, this paper design a novel all reflective zoom optical system which uses anti-telephoto construction with 3 mirrors. Firstly, using the zoom theory of differential, the initial configuration with 2 zoom ratio was obtained. Then simulating and optimizing the system with Zemax that is software of the optical design, we get a novel all reflective zoom optical system. It has a smaller obscuration and bigger field of view than traditional reflective zoom optical system. At last, the image qualities of this system was evaluated and concluded. And the image qualities of this novel all reflective zoom system is well and the construction of the optical system is reasonable. It can be applied in space optical system.

Zhang, Lifei; Chang, Jun; Wei, Aman; Cao, Jiao; Ouyang, Jiao

2012-11-01

33

Super-resolution wide-field optical microscopy by use of Evanescent standing waves  

E-print Network

The development of high resolution, high speed imaging techniques allows the study of dynamical processes in biological systems. Optical fluorescence microscopy is an essential tool for investigations in many disciplines ...

Chung, Euiheon

2007-01-01

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

Wide-field x-ray microscopy with Kirkpatrick-Baez optics  

Microsoft Academic Search

Modern technology permits the fabrication of Kirkpatrick-Baez (KB) multilayer optics with performance close to the theoretical limit. We have constructed a KB field-imaging microscope which operates in the x-ray energy range 6-10 keV with a field of view of 40-150 micrometers . The optics perform at a reflectivity of 80% at the first Bragg peak. Using highly-collimated synchrotron radiation, we

Terrence Jach; Stephen M. Durbin; Alex Bakulin; David S. Bright; Cristian Stagarescu; George Srajer; Daniel Haskel; Joseph Pedulla

2001-01-01

36

Fast active optics control of wide-field telescopes based on science image analysis  

NASA Astrophysics Data System (ADS)

We study a novel active optics control scheme at the VST on Cerro Paranal, an f/5:5 survey telescope with a 1x1 degree field of view and a 2.6m primary mirror. This scheme analyzes the elongation pattern of the star PSFs across the full science image (267 Mpixels) and compares their second moments with an analytical model based on 5th-order geometrical optics, comprising 9 degrees of freedom in mirror misalignments and deformations. Using a numerical optimization method, we can complete the star extraction and fitting process in under one minute, fast enough for effective closed-loop active optics control in survey observing cadences.

Holzlöhner, R.; Rakich, A.; Noethe, L.; Kuijken, K.; Schipani, P.

2014-07-01

37

On-sky wide field adaptive optics correction using multiple laser guide stars at the MMT  

E-print Network

We describe results from the first astronomical adaptive optics system to use multiple laser guide stars, located at the 6.5-m MMT telescope in Arizona. Its initial operational mode, ground-layer adaptive optics (GLAO), provides uniform stellar wavefront correction within the 2 arc minute diameter laser beacon constellation, reducing the stellar image widths by as much as 53%, from 0.70 to 0.33 arc seconds at lambda = 2.14 microns. GLAO is achieved by applying a correction to the telescope's adaptive secondary mirror that is an average of wavefront measurements from five laser beacons supplemented with image motion from a faint stellar source. Optimization of the adaptive optics system in subsequent commissioning runs will further improve correction performance where it is predicted to deliver 0.1 to 0.2 arc second resolution in the near-infrared during a majority of seeing conditions.

Christoph Baranec; Michael Hart; N. Mark Milton; Thomas Stalcup; Keith Powell; Miguel Snyder; Vidhya Vaitheeswaran; Don McCarthy; Craig Kulesa

2008-12-01

38

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

39

Implementation of wide-field integration of optic flow for autonomous quadrotor navigation  

Microsoft Academic Search

Insects are capable of robust visual navigation in complex environments using efficient information extraction and processing\\u000a approaches. This paper presents an implementation of insect inspired visual navigation that uses spatial decompositions of\\u000a the instantaneous optic flow to extract local proximity information. The approach is demonstrated in a corridor environment\\u000a on an autonomous quadrotor micro-air-vehicle (MAV) where all the sensing and

Joseph Conroy; Gregory Gremillion; Badri Ranganathan; James Sean Humbert

2009-01-01

40

Wide-field solar adaptive optics in a layer-oriented approach  

E-print Network

We discuss a layer-oriented approach to multi-conjugate adaptive optics (MCAO) in solar imaging. The technique is a complement to the current star-oriented MCAO and appears as a necessary alternative when large field sizes are desired in solar observations. The basic procedure of the layer oriented method is indicated, and its characteristics are then illustrated in terms of numerical simulations.

Kellerer, Aglaé

2014-01-01

41

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

42

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

43

Mosaicing for fast wide-field-of-view optical resolution photoacoustic microscopy  

NASA Astrophysics Data System (ADS)

The acquisition speed of previously reported mechanically-scanned Optical-Resolution Photoacoustic Microscopy (OR-PAM) systems has been limited by both laser pulse repetition rate and mechanical scanning speed. In this paper we introduce a mosaicing scheme wherein a grid of small sub-mm-scale field-of-view (FOV) patches are acquired in 0.5s per patch, and a 3-axis stepper-motor system is used to mechanically move the object to be imaged from patch-to-patch in less than 0.5s. Patch images are aligned and stitched to generate a large FOV image composite. This system retains the SNR-advantages of focused-transducer OR-PAM systems, and is a hybrid approach between optical-scanning and mechanical scanning. With this strategy we reduce the data acquisition time of previously reported large-FOV systems by a factor of around 23. SCID hairless mice are imaged. The wide-FOV, high-speed data acquisition OR-PAM system broadens the potential applications of the imaging modality.

Shao, Peng; Shi, Wei; Chee, Ryan K.; Forbrich, Alexander; Zemp, Roger J.

2012-02-01

44

Wide field adaptive optics correction for the GMT using natural guide stars  

NASA Astrophysics Data System (ADS)

The conceptual design of the Giant Magellan Telescope has four wavefront sensors used to maintain the shape and alignment of the segmented primary and secondary mirrors. In this paper, we show that by reading the sensors at 200 Hz, we can also compensate for low altitude turbulence. As a result, there is a large improvement in image quality, even at visible wavelengths, over the entire science field of view of the telescope. A minimum-variance reconstructor is presented that takes slope measurements from four stars of arbitrary location and magnitude and produces the optimal adaptive secondary mirror commands. The performance of the adaptive optics system in this mode is simulated using YAO, an end-to-end simulation tool. We present the results of trade studies performed to optimize the science return of the telescope.

van Dam, Marcos A.; Bouchez, Antonin H.; McLeod, Brian A.

2014-07-01

45

Pan-STARRS: a wide-field optical survey telescope array  

NASA Astrophysics Data System (ADS)

The Institute for Astronomy at the University of Hawaii is developing a large optical synoptic survey telescope system; the Panoramic Survey Telescope and Rapid Response System. Pan-STARRS will consist of an array of four 1.8m telescopes with very large (7 square degree) field of view, giving it an etendue larger than all existing survey instruments combined. Each telescope will be equipped with a 1 billion pixel CCD camera with low noise and rapid read-out, and the data will be reduced in near real time to produce both cumulative static sky and difference images, from which transient, moving and variable objects can be detected. Pan-STARRS will be able to survey up to ?6,000 square degrees per night to a detection limit of approximately 24th magnitude. This unique combination of sensitivity and rate of area coverage will open up many new possibilities in time domain astronomy. A major goal for the project is to survey potentially dangerous asteroids, where Pan-STARRS will be able to detect most objects down to 300m size, much smaller than the km size objects accessible to existing search programs. In addition, the Pan-STARRS data products will used to address a wide range of astronomical problems in the Solar System, the Galaxy, and the Cosmos at large. Here, we first outline the Pan-STARRS science goals and describe the survey modes needed to support these. We then describe the design and performance goals, the data processing pipeline, and we review the basic data products. Finally, we present results from simulations that demonstrate Pan-STARRS' capability for detecting potentially hazardous asteroids.

Kaiser, Nicholas

2004-10-01

46

Mechanical setup for optical aperture synthesis for wide-field imaging  

NASA Astrophysics Data System (ADS)

Homothetic mapping is a technique that combines the images from several telescopes so that it looks like as though they came form a single large telescope. This technique enables a much wider interferometric field of image than current techniques can provide. To investigate the feasibility, a research testbed is build know as Delft Testbed interferometer (DTI). DTI simulates a configuration of three telescopes collecting light of a set of 3 stars. The stars are simulated by coupling light of a Xenon light source into three fibres, which illuminate a parabolic mirror. The light that is used has wavelengths of 500 nm - 800 nm. The light of the three telescopes will be combined in such a way that the beam arrangement in the pupil plane corresponds with the telescope arrangement and the Optical Path Difference (OPD) is minimized for the three beams. To achieve white light fringes with high visibility, the mechanical testbed that is 2 m x 1 m x 0.5 m in size, requires stable mounting of components. This paper describes the mounting of the diamond turned off-axis parabolic mirrors of 200 mm in diameter and 240 mm flat mirrors; furthermore, it describes components like the telescopes and the active controllable components for repositioning of the beam arrangement. Mechanisms were developed for alignment of piezo actuators and for delay lines. The delay lines can also be used to compensate pupil rotation. Test results demonstrate that the test setup is highly stable for temperature as well as for airflow, although the system is placed in a non-thermally controlled lab. This allows measurements of nm, in presence of ?m disturbances.

Giesen, Peter; Ouwerkerk, Bas; van Brug, Hedser; van den Dool, Teun C.; van der Avoort, Casper

2004-10-01

47

Adaptive optics wide-field microscope corrections using a MEMS DM and Shack-Hartmann wavefront sensor  

NASA Astrophysics Data System (ADS)

We demonstrated the used of an adaptive optic system in biological imaging to improve the imaging characteristics of a wide field microscope. A crimson red fluorescent bead emitting light at 650 nm was used together with a Shack-Hartmann wavefront sensor and deformable mirror to compensate for the aberrations introduce by a Drosophila embryo. The measurement and correction at one wavelength improves the resolving power at a different wavelength, enabling the structure of the sample to be resolved (510 nm). The use of the crimson beads allow for less photobleaching to be done to the science object of the embryo, in this case our GFP model (green fluorescent beads), and allows for the science object and wavefront reference to be spectrally separated. The spectral separation allows for single points sources to be used for wavefront measurements, which is a necessary condition for the Shack-Hartmann Wavefront sensor operation.

Azucena, Oscar; Tao, Xiaodong; Crest, Justin; Kotadia, Shaila; Sullivan, William; Gavel, Donald; Reinig, Marc; Olivier, Scot; Kubby, Joel

2011-03-01

48

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

PubMed

Wide-field astronomy requires the development of larger aperture telescopes. The optical properties of a three-mirror modified-Rumsey design provide significant advantages when compared to other telescope designs: (i) at any wavelength, the design has a flat field and is anastigmatic; (ii) the system is extremely compact, i.e., it is almost four times shorter than a Schmidt. Compared to the equally compact flat-field Ritchey-Chrétien with a doublet-lens corrector, as developed for the Sloan digital sky survey-and which requires the polishing of six optical surfaces-the proposed modified-Rumsey design requires only a two-surface polishing and provides a better imaging quality. All the mirrors are spheroids of the hyperboloid type. Starting from the classical Rumsey design, it is shown that the use of all eight available free parameters allows the simultaneous aspherization of the primary and tertiary mirrors by active optics methods from a single deformable substrate. The continuity conditions between the primary and the tertiary hyperbolizations are achieved by an intermediate narrow ring of constant thickness that is not optically used. After the polishing of a double vase form in a spherical shape, the primary-tertiary hyperbolizations are achieved by in situ stressing. The tulip-form secondary is hyperbolized by stress polishing. Other active optics alternatives are possible for a space telescope. The modified-Rumsey design is of interest for developing large space- and ground-based survey telescopes in UV, visible, or IR ranges, such as currently demonstrated with the construction of identical telescopes MINITRUST-1 and -2, f/5-2 degrees field of view. Double-pass optical tests show diffraction-limited images. PMID:16353802

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

2005-12-01

49

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

50

Wide-Field Astrophotography  

NASA Astrophysics Data System (ADS)

Wide-field astrophotography is generally defined as celestial photographyusing a consumer-grade camera or a specialized astrograph without shootingthrough a telescope (see also WIDEFIELD CCD IMAGERS).As practiced by the amateur astronomer, wide-field astrophotography usesreadily available 35 mm and medium format cameras to photograph celestialphenomena using the various lenses available for these ...

Reeves, R.; Murdin, P.

2002-12-01

51

Optomechanical design concept for GMACS: a wide-field multi-object moderate resolution optical spectrograph for the Giant Magellan Telescope (GMT)  

NASA Astrophysics Data System (ADS)

We describe the conceptual optomechanical design for GMACS, a wide-field, multi-object, moderate-resolution optical spectrograph for the Giant Magellan Telescope (GMT). GMACS is a candidate first-light instrument for the GMT and will be one of several instruments housed in the Gregorian Instrument Rotator (GIR) located at the Gregorian focus. The instrument samples a 9 arcminute x 18 arcminute field of view providing two resolution modes (i.e, low resolution, R ~ 2000, and moderate resolution, R ~ 4000) over a 3700 Å to 10200 Å wavelength range. To minimize the size of the optics, four fold mirrors at the GMT focal plane redirect the full field into four individual "arms", that each comprises a double spectrograph with a red and blue channel. Hence, each arm samples a 4.5 arcminute x 9 arcminute field of view. The optical layout naturally leads to three separate optomechanical assemblies: a focal plane assembly, and two identical optics modules. The focal plane assembly contains the last element of the telescope's wide-field corrector, slit-mask, tent-mirror assembly, and slit-mask magazine. Each of the two optics modules supports two of the four instrument arms and houses the aft-optics (i.e. collimators, dichroics, gratings, and cameras). A grating exchange mechanism, and articulated gratings and cameras facilitate multiple resolution modes. In this paper we describe the details of the GMACS optomechanical design, including the requirements and considerations leading to the design, mechanism details, optics mounts, and predicted flexure performance.

Smee, Stephen A.; Prochaska, Travis; Shectman, Stephen A.; Hammond, Randolph P.; Barkhouser, Robert H.; DePoy, D. L.; Marshall, J. L.

2012-09-01

52

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

53

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

SciTech Connect

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

Magakian, Tigran Yu.; Nikogossian, Elena H.; Movsessian, Tigran [Byurakan Astrophysical Observatory, 378433 Aragatsotn reg. (Armenia); Aspin, Colin [Institute for Astronomy, University of Hawaii, 640 North A'ohoku Place, Hilo, HI, 96720 (United States); Pyo, Tae-Soo [Subaru Telescope, National Astronomical Observatory of Japan, 650 North A'ohoku Place, Hilo, HI 96720 (United States); Khanzadyan, Tigran [Centre for Astronomy, School of Physics, National University of Ireland Galway, University Road, Galway (Ireland); Smith, Michael D.; Mitchison, Sharon [Centre for Astrophysics and Planetary Science, School of Physical Sciences, University of Kent, Canterbury CT2 7NR (United Kingdom); Davis, Chris J. [Joint Astronomy Centre, 660 North A'ohoku Place, University Park, Hilo, Hawaii 96720 (United States); Beck, Tracy L. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Moriarty-Schieven, Gerald H. [NRC Herzberg Institute of Astrophysics, 5071 West Saanich Road Victoria, British Columbia, V9E 2E7 (Canada)], E-mail: tigmag@sci.am, E-mail: elena@bao.sci.am, E-mail: caa@ifa.hawaii.edu, E-mail: pyo@subaru.naoj.org, E-mail: tigran.khanzadyan@nuigalway.ie, E-mail: smm23@kent.ac.uk, E-mail: m.d.smith@kent.ac.uk, E-mail: c.davis@jach.hawaii.edu, E-mail: tbeck@stsci.edu, E-mail: gerald.schieven@nrc-cnrc.gc.ca

2010-03-15

54

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

NASA Astrophysics Data System (ADS)

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

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

2010-11-01

55

Brightest X-ray clusters of galaxies in the CFHTLS wide fields: Catalog and optical mass estimator  

E-print Network

The CFHTLS presents a unique data set for weak lensing studies, having high quality imaging and deep multi-band 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, allows us to revisit the identification of X-ray sources, introducing automated reproducible algorithms, based on the multi-color red sequence finder. We have also introduced a new optical mass proxy. We provide the calibration of the red sequence observed in the CFHT filters and compare the results with the traditional single color red sequence and photoz. 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 multi-color red sequence to...

Mirkazemi, M; 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

2014-01-01

56

Wide field corrector for the KMTNet telescope  

NASA Astrophysics Data System (ADS)

We present the design, assembly, alignment, and verification process of the wide field corrector for the Korea Microlensing Telescope Network (KMTNet) 1.6 meter optical telescope. The optical configuration of the KMTNet telescope is prime focus, having a wide field corrector and the CCD camera on the topside of Optical Tube Assembly (OTA). The corrector is made of four lenses designed to have all spherical surfaces, being the largest one of 552 mm physical diameter. Combining with a purely parabolic primary mirror, this optical design makes easier to fabricate, to align, and to test the wide field optics. The centering process of the optics in the lens cell was performed on a precision rotary table using an indicator. After the centering, we mounted three large and heavy lenses on each cell by injecting the continuous Room Temperature Vulcanizing (RTV) silicon rubber bonding via a syringe.

Lee, Yongseok; Cha, Sang-Mok; Poteet, Wade; Lam, Philip; Lee, Chung-Uk; Kim, Seung-Lee; Park, Byeong-Gon; Buchroeder, Richard A.; Jin, Ho

2014-07-01

57

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

58

Automatic Detection of Asteroids and Meteoroids - A Wide Field Survey  

E-print Network

We propose a low-cost robotic optical survey aimed at $1-300$ m Near Earth Objects (NEO) based on four state-of-the-art telescopes having extremely wide field of view. The small Near-Earth Asteroids (NEA) represent a potential risk but also easily accessible space resources for future robotic or human space in-situ exploration, or commercial activities. The survey system will be optimized for the detection of fast moving - trailed - asteroids, space debris and will provide real-time alert notifications. The expected cost of the system including 1-year development and 2-year operation is 1,000,000 EUR. The successful demonstration of the system will promote cost-efficient ADAM-WFS (Automatic Detection of Asteroids and Meteoroids - A Wide Field Survey) systems to be built around the world.

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

2014-01-01

59

Automatic detection of asteroids and meteoroids. A Wide Field Survey  

NASA Astrophysics Data System (ADS)

We propose a low-cost robotic optical survey aimed at 1-300 m Near Earth Objects (NEO) based on four state-of-the-art telescopes having extremely wide field of view. The small Near-Earth Asteroids (NEA) represent a potential risk but also easily accessible space resources for future robotic or human space in-situ exploration, or commercial activities. The survey system will be optimized for the detection of fast moving-trailed-asteroids, space debris and will provide real-time alert notifications. The expected cost of the system including 1-year development and 2-year operation is 1,000,000 EUR. The successful demonstration of the system will promote cost-effectiveicient ADAM-WFS (Automatic Detection of Asteroids and Meteoroids -- A Wide Field Survey) systems to be built around the world.

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

2014-07-01

60

Wide-field VLBI Imaging  

E-print Network

We discuss the technique of Wide-field imaging as it applies to Very Long Baseline Interferometry (VLBI). In the past VLBI data sets were usually averaged so severely that the field-of-view was typically restricted to regions extending a few hundred milliarcseconds from the phase centre of the field. Recent advances in data analysis techniques, together with increasing data storage capabilities, and enhanced computer processing power, now permit VLBI images to be made whose angular size represents a significant fraction of an individual antenna's primary beam. This technique has recently been successfully applied to several large separation gravitational lens systems, compact Supernova Remnants in the starburst galaxy M82, and two faint radio sources located within the same VLA FIRST field. It seems likely that other VLBI observing programmes might benefit from this wide-field approach to VLBI data analysis. With the raw sensitivity of global VLBI set to improve by a factor 4-5 over the coming few years, the number of sources that can be detected in a given field will rise considerably. In addition, a continued progression in VLBI's ability to image relatively faint and extended low brightness temperature features (such as hot-spots in large-scale astrophysical jets) is also to be expected. As VLBI sensitivity approaches the $\\mu$Jy level, a wide-field approach to data analysis becomes inevitable.

M. A. Garrett; R. W. Porcas; A. Pedlar; T. W. B. Muxlow; S. T. Garrington

1999-06-07

61

The XMM-Newton Wide-Field Survey in the COSMOS Field. III. Optical Identification and Multiwavelength Properties of a Large Sample of X-Ray-Selected Sources  

NASA Astrophysics Data System (ADS)

We present the optical identification of a sample of 695 X-ray sources detected in the first 1.3 deg2 of the COSMOS XMM-Newton survey, down to a 0.5-2 keV (2-10 keV) limiting flux of ~10-15 erg cm-2 s-1 (~5×10-15 erg cm-2 s-1). In order to identify the correct optical counterparts and to assess the statistical significance of the X-ray-to-optical associations we have used the ``likelihood ratio technique.'' Here we present the identification method and its application to the CFHT I-band and photometric catalogs. We were able to associate a candidate optical counterpart to ~90% (626) of the X-ray sources, while for the remaining ~10% of the sources we were not able to provide a unique optical association due to the faintness of the possible optical counterparts (IAB>25) or to the presence of multiple optical sources, with similar likelihoods of being the correct identification, within the XMM-Newton error circles. We also cross-correlated the candidate optical counterparts with the Subaru multicolor and ACS catalogs and with the Magellan/IMACS, zCOSMOS, and literature spectroscopic data; the spectroscopic sample comprises 248 objects (~40% of the full sample). Our analysis of this statistically meaningful sample of X-ray sources reveals that for ~80% of the counterparts there is a very good agreement between the spectroscopic classification, the morphological parameters as derived from ACS data, and the optical-to-near-infrared colors: the large majority of spectroscopically identified broad-line active galactic nuclei (BL AGNs) have a pointlike morphology on ACS data, blue optical colors in color-color diagrams, and an X-ray-to-optical flux ratio typical of optically selected quasars. Conversely, sources classified as narrow line AGNs or normal galaxies are on average associated with extended optical sources, have significantly redder optical-to-near-infrared colors, and span a larger range of X-ray-to-optical flux ratios. However, about 20% of the sources show an apparent mismatch between the morphological and spectroscopic classifications. All the ``extended'' BL AGNs lie at redshift <1.5, while the redshift distribution of the full BL AGN population peaks at z~1.5. The most likely explanation is that in these objects the nuclear emission is not dominant with respect to the host galaxy emission in the observed ACS band. Our analysis also suggests that the type 2/type 1 ratio decreases toward high luminosities, in qualitative agreement with the results from X-ray spectral analysis and the most recent modeling of the X-ray luminosity function evolution. Based on observations obtained with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States and NASA; also based on data collected at the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc. (AURA), under NASA contract NAS 5-26555 the Subaru Telescope, which is operated by the National Astronomical Observatory of Japan; the European Southern Observatory, Chile, under Large Program 175.A-0839 Kitt Peak National Observatory, Cerro Tololo Inter-American Observatory, and the National Optical Astronomy Observatory, which are operated by the Association of Universities for Research in Astronomy, Inc. (AURA), under cooperative agreement with the National Science Foundation; and the Canada-France-Hawaii Telescope operated by the National Research Council of Canada, the Centre National de la Recherche Scientifique de France and the University of Hawaii.

Brusa, M.; Zamorani, G.; Comastri, A.; Hasinger, G.; Cappelluti, N.; Civano, F.; Finoguenov, A.; Mainieri, V.; Salvato, M.; Vignali, C.; Elvis, M.; Fiore, F.; Gilli, R.; Impey, C. D.; Lilly, S. J.; Mignoli, M.; Silverman, J.; Trump, J.; Urry, C. M.; Bender, R.; Capak, P.; Huchra, J. P.; Kneib, J. P.; Koekemoer, A.; Leauthaud, A.; Lehmann, I.; Massey, R.; Matute, I.; McCarthy, P. J.; McCracken, H. J.; Rhodes, J.; Scoville, N. Z.; Taniguchi, Y.; Thompson, D.

2007-09-01

62

Okayama astrophysical observatory wide field camera  

NASA Astrophysics Data System (ADS)

Okayama Astrophysical Observatory Wide Field Camera: OAOWFC is a near-infrared (0.9-2.5 ?m) survey telescope, whose aperture is 0.91m. It works at Y, J, H, and Ks bands. The optics are consisted of forward Cassegrain and quasi Schmidt which yield the image circle of ? 52 mm or ? 1.3 deg at the focal plane. The overall F-ratio is F/2.51 which is one of the fastest among near infrared imagers in the world. A HAWAII-1 detector array placed at the focal plane cuts the central 0.48 deg. x 0.48 deg. with a pixel scale of 1.67 arcsec/pix. It will be used to survey the Galactic plane for variability and search for transients such as Gamma-ray burst afterglows optical counterpart of gravitational wave sources.

Yanagisawa, Kenshi; Shimizu, Yasuhiro; Okita, Kiichi; Kuroda, Daisuke; Koyano, Hisashi; Tsutsui, Hironori; Toda, Hiroyuki; Izumiura, Hideyuki; Yoshida, Michitoshi; Ohta, Kouji; Kawai, Nobuyuki; Yamamuro, Tomoyasu

2014-08-01

63

Gemini Frontier Fields: Wide-field Adaptive Optics $K_s$-band Imaging of the Galaxy Cluster MACS J0416.1-2403  

E-print Network

The Hubble Space Telescope (HST) Frontier Fields Campaign targets six massive clusters of galaxies, exploiting the strong gravitational lensing effect to study the distant Universe. At Gemini South we observe the three southern-most clusters in Ks-band, overcoming HST/WFC3's sensitivity cut-off redwards of 1.7 microns. We use the Gemini Multi-Conjugate Adaptive Optics System (GeMS) and the Gemini South Adaptive Optics Imager (GSAOI), delivering near diffraction-limited images on arcminute scales. In this paper we describe our public release of 100"x110" wide images of the first target, MACS J0416.1-2403. We have achieved an angular resolution of 0.07"-0.10", twice as high as HST/WFC3, with only one natural guide star. With a $5\\sigma$ depth of Ks=23.8 mag for extended sources our images are shallower than the HST/WFC3 images. The data were distortion corrected and registered with sub-pixel accuracy despite only a few low-S/N extended sources are visible in the individual exposures. This is a demonstration tha...

Schirmer, Mischa; Pessev, Peter; Garrel, Vincent; Winge, Claudia; Neichel, Benoit; Vidal, Fabrice

2014-01-01

64

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

NASA Astrophysics Data System (ADS)

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 subfields 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 subfields are identified and used for simulations of AO correction. We achieve ensquared energies within 75 mas of between 25-35 per cent depending on the subfield, which is sufficient to probe sub-kpc scales in high-redshift galaxies. We also investigate the effect of detector readout noise on AO system performance, and consider cases where natural guide stars are used for both high-order and tip-tilt-only AO correction. We also consider how performance scales with ensquared energy box size. In summary, the expected AO performance is sufficient for a MOSAIC-like instrument, even within deep fields characterized by a lack of bright foreground stars.

Basden, A. G.; Evans, C. J.; Morris, T. J.

2014-12-01

65

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

66

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

67

Image formation in structured illumination wide-field fluorescence microscopy  

Microsoft Academic Search

We present a theoretical analysis of the image formation in structured illumination wide-field fluorescence microscopy (SIWFFM). We show that the optically sectioned images obtained with this approach possess the optical sectioning strengths comparable to those obtained with the confocal microscope. We further show that the transfer function behaviour is directly comparable to that of the true confocal instrument. The theoretical

Dejan Karadaglica; Tony Wilson

2008-01-01

68

Wide field performance of a phased array telescope  

Microsoft Academic Search

A phased array telescope is an array of optical telescopes whose images are coherently combined so as to achieve the resolution of a single but much large telescope. Phased array telescopes deliver the resolution of very large telescopes without the difficulties and expenses associated with very large optics. To achieve this resolution, a wide field of view (FOV) phased array

Christopher R. DeHainaut; Dennis C. Duneman; Raymond C. Dymale; Joseph P. Blea; Burton D. O'Neil; Carol E. Hines

1995-01-01

69

Wide-field high-resolution structured illumination solid immersion fluorescence microscopy  

NASA Astrophysics Data System (ADS)

The use of aplanatic solid immersion lenses (ASILs) made of high-refractive-index optical materials provides a route to wide-field high-resolution optical microscopy. Structured illumination microscopy (SIM) can double the spatial bandwidth of a microscope to also achieve high-resolution imaging. We investigate the combination of ASILs and SIM in fluorescence microscopy, which we call structured illumination solid immersion fluorescence microscopy (SISIM), to pursue a microscopic system with very large NA and high lateral resolution. We demonstrate that the combination can produce a wide-field high-resolution microscopic system with bandwidth corresponding to an NA of 3. Future developments of the SISIM system to make it achieve even higher resolution are proposed.

Wang, Lin; Pitter, Mark C.; Somekh, Michael G.

2011-08-01

70

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

71

Wide field camera 3 ground testing and calibration  

Microsoft Academic Search

Wide Field Camera 3 (WFC3), a panchromatic imager developed for the Hubble Space Telescope (HST), is fully integrated with its flight detectors and has undergone several rounds of ground testing and calibration at Goddard Space Flight Center (GSFC). The testing processes are highly automated, with WFC3 and the optical stimulus, which is used to provide external targets and illumination, being

H. Bushouse; S. Baggett; H. Bond; T. Brown; S. Deustua; G. F. Hartig; B. Hilbert; R. J. Hill; J. Kim-Quijano; R. A. Kimble; J. W. MacKenty; A. Martel; P. McCullough; L. Petro; S. Rinehart; M. Robberto

2008-01-01

72

Wide field imaging of distant clusters  

E-print Network

Wide field imaging is key to understanding the build-up of distant clusters and their galaxy population. By focusing on the so far unexplored outskirts of clusters, where infalling galaxies first hit the cluster potential and the hot intracluster medium, we can help separate cosmological field galaxy evolution from that driven by environment. I present a selection of recent advancements in this area, with particular emphasis on Hubble Space Telescope wide field imaging, for its superior capability to deliver galaxy morphologies and precise shear maps of distant clusters.

T. Treu

2004-08-05

73

Wide-Field Camera 3 Ground Testing and Calibration  

Microsoft Academic Search

Wide Field Camera 3 (WFC3), a panchromatic UV\\/Optical\\/IR imager being developed for the Hubble Space Telescope (HST), underwent a lengthy thermal-vacuum testing and calibration process during the summer of 2007. A full suite of instrument calibrations was performed, including measurements of basic detector properties such as dark current, read noise, flat field response, gain, and linearity. System level tests of

Howard A. Bushouse; S. Baggett; H. Bond; T. Brown; G. Hartig; B. Hilbert; R. Hill; J. Kim; R. Kimble; J. MacKenty; A. Martel; P. McCullough; L. Petro; S. Rinehart; M. Robberto

2007-01-01

74

The Wide-Field Infrared Explorer  

NASA Astrophysics Data System (ADS)

We propose to build a Wide Field Infrared Explorer (WIRE) in response to NASA's 1992 Announcement of Opportunity for Small Explorers. WIRE will be capable of detecting typical starburst galaxies at a redshift of 0.5, ultraluminous infrared galaxies beyond a redshift of 2, and luminous protogalaxies beyond a redshift of 5. This instrument will survey about 100 deg(2) of high Galactic latitude sky at 12 and 25 microns, in passbands where 20% of the luminosity from local starbursts is radiated. WIRE will measure the 12--25 microns color of the starburst galaxies, which is a powerful statistical luminosity indicator. The distribution of starburst galaxy 12--25 microns colors as a function of flux density will reveal their evolutionary history and perhaps the presence of protogalaxies at high redshifts. Follow-up observations of a subset of the WIRE survey will provide a test of our assumptions in using the flux-color distribution to determine the evolution of starburst galaxies. The objective of the WIRE mission is to answer the following questions: (1) What fraction of the luminosity of the Universe at a redshift of 0.5 and beyond is due to starburst galaxies? (2) How fast and in what ways are starburst galaxies evolving? (3) Are luminous protogalaxies common at redshifts less than 3? During its four-month mission lifetime, WIRE will gather ample data to answer these questions and amass a catalog exceeding the size of the IRAS Point Source Catalog. If starburst galaxies are evolving at a modest pace, then a three-hour exposure will reach flux densities below 0.4 mJy, 5sigma , and will be dominated by confusion noise. WIRE is specifically designed to detect the maximum number of high-redshift starburst galaxies using the smallest, simplest instrument possible. The 28cm aperture Cassegrain telescope has no moving parts and a wide 34 times 34 arcminute field of view. It capitalizes on the 128 times 128 Si:As IBC detector arrays now available. The optics and detectors are cooled during the mission using only 3 kg of solid H_2. The WIRE instrument requires only a single stare-type observing mode, fixed solar panel, 35 watts of power, and a low data rate (7 kbits/sec average). The WIRE survey will be over 500 times fainter than the IRAS Faint Source Survey at 12 and 25 microns. This revolutionary gain in sensitivity over a significant part of the sky permits breakthroughs in all areas of astronomy.

Hacking, P.; Schember, H.

1993-05-01

75

Wide field imaging problems in radio astronomy  

Microsoft Academic Search

The new generation of synthesis radio telescopes now being proposed, designed, and constructed face substantial problems in making images over wide fields of view. Such observations are required either to achieve the full sensitivity limit in crowded fields or for surveys. The Square Kilometre Array (SKA Consortium, Tech. Rep., 2004), now being developed by an international consortium of 15 countries,

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

2005-01-01

76

Sensitivity analysis of a wide-field telescope  

NASA Astrophysics Data System (ADS)

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

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

2013-07-01

77

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

78

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

79

Optical Technology Needs for Future Space Telescopes  

E-print Network

Optical Technology Needs for Future Space Telescopes H. Philip Stahl, Ph.D. #12;Prelude instruments & sensors. Future Space Telescopes will operate over broad spectrum: Gamma Rays, X-Rays, XUV Structure #12;NASA's Science Missions Directorate Themes: Earth Science Sun-Solar System Connection Solar

Van Stryland, Eric

80

Star Counts in the NOAO Deep Wide-Field Survey  

NASA Astrophysics Data System (ADS)

The NOAO Deep Wide-Field Survey will survey two ~ 9 sq. deg. regions of sky in a suite of optical (Bw, R, I) and infrared (J, H, K) bands. Although designed primarily to study the formation and large scale structure of galaxies, the survey can also be used to identify rare stellar populations in the Galaxy and to study Galactic structure. Here we compare the Bw, R, and I star counts in a small portion of the Cetus field of the NOAO Deep Wide-Field Survey with the counts predicted by a simple Galactic structure model. The comparison is used to explore the accuracy of catalog-generation programs such as Source Extractor in performing star-galaxy separation at faint magnitudes. The NOAO Deep Wide-Field Survey is being supported by the National Optical Astronomy Observatory which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the National Science Foundation. Michael Cooper's research was supported by the NOAO/KPNO REU Program, funded by the National Science Foundation.

Cooper, M.; Najita, J.; Dey, A.; Jannuzi, B. T.

2000-12-01

81

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

82

Wide-Field Camera 3 Ground Calibration  

Microsoft Academic Search

Wide-Field Camera 3 (WFC3), a panchromatic imager being developed for the Hubble Space Telescope (HST), is now fully integrated and over the past 9 months has completed first rounds of extensive ground testing at Goddard Space Flight Center, in both ambient and thermal-vacuum test environments. The thermal-vacuum testing marks the first time that both of the WFC3's UV\\/Visible and IR

H. Bushouse; S. Baggett; T. Brown; G. Hartig; B. Hilbert; J. MacKenty; I. N. Reid; M. Robberto; W. Baggett; B. Hill; R. Kimble; O. Lupie; T. Pham

2004-01-01

83

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

84

Recent progress in wide-field imaging interferometry  

NASA Astrophysics Data System (ADS)

The Wide-Field Imaging Interferometry Testbed (WIIT) at NASA's Goddard Space Flight Center and a computational model of the testbed were developed to demonstrate and learn the practical limitations of techniques for wide-field spatial-spectral ("double Fourier") interferometry. WIIT is an automated and remotely operated system, and it is now producing substantial amounts of high-quality data from its state-of-the-art operating environment, Goddard's Advanced Interferometry and Metrology Lab. In this paper, we discuss the characterization and operation of the testbed and present recently acquired data. We also give a short description of the computational model and its applications. Finally, we outline future research directions. A companion paper within this conference discusses the development of new widefield double Fourier data analysis algorithms.

Rinehart, S. A.; Leisawitz, D. T.; Bolcar, M. R.; Chaprnka, K. M.; Lyon, R. G.; Maher, S. F.; Memarsadeghi, N.; Sinukoff, E. J.; Teichman, E.

2010-07-01

85

Experimental comparison of Wide Field AO control schemes using the Homer AO bench.  

NASA Astrophysics Data System (ADS)

Wide Field Adaptive Optics (WFAO) concepts, such as Laser Tomography AO (LTAO) or Multi-Conjugate AO (MCAO) have been developed in order to overcome the anisoplanatism limit of classical AO. Most of the future AO-assisted instruments of ELTs rely on such concepts which have raised critical challenges such as tomographic estimation and from laser and natural guide star combined with efficient DM(s) control. In that context, the experimental validation of the various clever control solutions proposed by several teams in the past years is now essential to reach a level of maturity compatible with their implementation in future WFAO developments for ELT. The ONERA wide field AO facility (HOMER bench) has been developed for these very issues. Gathering a 3D turbulence generator, laser and natural guide stars, two deformable mirrors with variable altitude positions and a PC-based flexible and user-friendly RTC , HOMER allows the implementation and comparison of control schemes from the simplest least-square to the optimal Linear Quadratic Gaussian solutions including Virtual DM and Pseudo-closed loop approaches. After a description of the bench internal calibrations and ultimate performance, all the control schemes are compared experimentally. Their evolutions as a function of wavefront sensors SNR as well as their robustness to calibration / model errors are particularly emphasised. Finally, we derive from the previous works some specific calibrations and identifications procedures ensuring both robustness and efficiency of WFAO systems and we extrapolate their applications to the future ELT AO systems.

Parisot, Amélie; Petit, Cyril; Fusco, Thierry

2011-09-01

86

Imaging of small particles using wide-field confocal microscopy  

NASA Astrophysics Data System (ADS)

Particle measurement is important in many applications such as the manufacture of drugs and paints, and aerosols. In bioimaging there is interest understanding the imaging of nanoparticles and subcellular scatterers. We present in this paper a wide field, phase measuring confocal microscope that can be used for such measurements. The wide field confocal response is obtained by illuminating both sample and reference arms of an interferometric microscope with nominally identical speckle patterns. When the speckle patterns are highly correlated the interference is significant. Contributions from out of focus planes result in uncorrelated speckle patterns and no interference. This provides a wide field confocal response. High speed measurements are enabled by parallel phase stepping using polarization optics. We have also developed a vector diffraction microscope model, using Mie theory as a scattering function, to validate the images of small particles. Correctly scaling the amplitudes of the unscattered and scattered electric fields enables co-polar transmission imaging to be modeled. Finally it is demonstrated that the phase is a more sensitive measurement of particle size than the amplitude.

Morgan, Stephen P.; Sawyer, N. B. E.; Somekh, Michael G.; See, Chung Wah; Shekunov, B. Y.; Astrakharchik, E.

2003-10-01

87

WINGS: WIde-field Nearby Galaxy-cluster Survey  

NASA Astrophysics Data System (ADS)

WINGS is a multiwavelength survey of 77 nearby (0.041043.5 erg/s) Galaxy Clusters. The main goal of this survey is to establish the zero point for evolutionary studies of clusters and galaxies in clusters. I will describe the different components of the WINGS project which includes: * Photometry - Optical (B,V) wide-field (˜30x30') deep photometry of 77 fields (Varela et al,2006). Catalogs contain ˜6x105 objects classified as stars and galaxies. Position, basic photometry (total magnitude and aperture photometry) and geometrical parameters (isophotal area, ellipticity, position angle,...) have been measured for each object. For the 10% largest galaxies surface photometry and objective morphological classification is also being performed with special designed tools. Images and catalogs will be publicly available. - NIR (J,K) wide field imaging focus on stellar mass analysis. - U and H? wide field imaging for analysis of the star formation characteristics of the galaxies. - Other on-going photometric follow-up programs: Ultra-wide-field (˜1deg x 1deg) imaging in UBV to study the outer parts of the clusters of galaxies and their infalling regions; search for Ultra Compact Dwarf galaxies. * Spectroscopy - Spectra have been already taken for a subsample of 51 fields (˜100-200 galaxies per field) covering the wavelength range ˜3600-8000 Angstrom. This allows to obtain redshifts, for cluster membership and dynamical studies, as well as to analyse the star formation history, extinction and stellar masses of the different stellar populations that compound galaxies. Some of the first scientific results will also be presented.

Varela, Jesüs

2007-05-01

88

Wide-field telescope design for the KMTNet project  

NASA Astrophysics Data System (ADS)

The Korea Astronomy and Space Science Institute (KASI) are under development three 1.6m optical telescopes for the Korea Micro-lensing Telescope Network (KMTNet) project. These will be installed at three southern observatories in Chile, South Africa, and Australia by middle 2014 to monitor dense star fields like the Galactic bulge and Large Magellanic Cloud. The primary scientific goal of the project is to discover numerous extra-solar planets using the gravitational micro-lensing technique. We have completed the final design of the telescope. The most critical design issue was wide-field optics. The project science requires the Delivered Image Quality (DIQ) of less than 1.0 arcsec FWHM within 1.2 degree radius FOV, under atmospheric seeing of 0.75 arcsec. We chose the prime-focus configuration and realized the DIQ requirement by using a purely parabolic primary mirror and four corrector lenses with all spherical surfaces. We present design results of the wide-field optics, the primary mirror coating and support, and the focus system with three linear actuators on the head ring.

Kim, Seung-Lee; Park, Byeong-Gon; Lee, Chung-Uk; Kappler, Larry; Kappler, Nathan; Poteet, Wade; Cauthen, Harold; Blanco, Dan; Buchroeder, Richard; Teran, Jose; Freestone, Scott; Lee, Jong-Ung; Cho, Myung; Yuk, In-Soo; Chun, Moo-Young; Jin, Ho; Cha, Sang-Mok

2011-10-01

89

Telescopes for Future UV/Optical Astronomy  

NASA Astrophysics Data System (ADS)

Future UV/Optical telescopes will require increasingly large apertures to answer the questions raised by HST, JWST, Planck and Herschel, and to complement the 30-m ground-based telescopes that will be coming on line in the next decade. Large aperture telescopes are required to provide the spatial resolution and sensitivity needed to perform frontier measurements of the future. These include stellar photometry and archaeology of distant galaxies, ultraviolet spectroscopy of the cosmic web, and high resolution imaging that will probe the formation and structure of the first galaxies, the properties of dark matter, and the evolutionary phases of pre-planetary systems. Low-cost, lightweight optics are required to enable the development of such large aperture UV / Optical telescopes in the 2020 decade. Technologies are therefore required that provide a high degree of thermal and dynamic stability, and wave front sensing and control, while minimizing the factors which drive the cost of flagship missions -- complexity, testing challenges, and mass.

Martin, Christopher D.

2012-01-01

90

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

91

The LOFT Wide Field Monitor simulator  

E-print Network

We present the simulator we developed for the Wide Field Monitor (WFM) aboard the Large Observatory For X-ray Timing (LOFT) mission, one of the four ESA M3 candidate missions considered for launch in the 2022-2024 timeframe. The WFM is designed to cover a large FoV in the same bandpass as the Large Area Detector (LAD, almost 50% of its accessible sky in the energy range 2-50 keV), in order to trigger follow-up observations with the LAD for the most interesting sources. Moreover, its design would allow to detect transient events with fluxes down to a few mCrab in 1-day exposure, for which good spectral and timing resolution would be also available (about 300 eV FWHM and 10 {\\mu}s, respectively). In order to investigate possible WFM configurations satisfying these scientific requirements and assess the instrument performance, an end-to-end WFM simulator has been developed. We can reproduce a typical astrophysical observation, taking into account both mask and detector physical properties. We will discuss the WF...

Donnarumma, I; Campana, R; Zand, J in't; Feroci, M; Lund, N; Brandt, S; Wilms, J; Schmid, C

2012-01-01

92

Wide field of view phased array telescope  

Microsoft Academic Search

The Multipurpose Multiple Telescope Testbed is described, and initial tests are discussed. After the optical quality of individual telescopes was established with interferometric tests, the cophasing and image superpositioning accuracy of the array were measured using star tests. Point spread functions were calculated with a physical optics code. Preliminary star tests using two of the four telescopes are presented and

C. R. de Hainaut; D. K. Marker; D. C. Duneman; R. C. Dymale; J. P. Blea

1990-01-01

93

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

E-print Network

We describe a methodology to classify periodic variable stars identified in the Wide-field Infrared Survey Explorer (WISE) full-mission single-exposure Source Database. This will assist in the future construction of a WISE periodic-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...

Masci, Frank J; Grillmair, Carl J; Cutri, Roc M

2014-01-01

94

Wide-field Imaging Interferometry Testbed II Implementation, Performance, and Plans  

E-print Network

The Wide-Field Imaging Interferometry Testbed (WIIT) will provide valuable information for the development of space-based interferometers. This laboratory instrument operates at optical wavelengths and provides the ability to test operational algorithms and techniques for data reduction of interferometric data. Here we present some details of the system design and implementation, discuss the overall performance of the system to date, and present our plans for future development of WIIT. In order to make best use of the interferometric data obtained with this system, it is critical to limit uncertainties within the system and to accurately understand possible sources of error. The WIIT design addresses these criteria through a number of ancillary systems. The use of redundant metrology systems is one of the most important features of WIIT, and provides knowledge of the delay line position to better than 10 nm. A light power detector is used to monitor the brightness of our light sources to ensure that small fl...

Rinehart, S A; Leisawitz, D T; Leviton, D B; Martino, A J; Maynard, W L; Mundy, L G; Teng, S H; Zhang, X; Frey, Bradley J.; Leisawitz, David T.; Leviton, Douglas B.; Martino, Anthony J.; Maynard, William L.; Mundy, Lee G.; Teng, Stacy H.; Zhang, Xiaolei

2002-01-01

95

OAOWFC: Okayama Astrophysical Observatory NIR Wide-Field Camera  

SciTech Connect

In order to detect and trace the early phase of near-infrared (NIR) afterglows of Gamma Ray Bursts (GRBs) quickly, we are now developing the Okayama Astrophysical Observatory Wide-Field Camera, OAOWFC. The aperture size of OAOWFC is 91 cm. The focal plane is covered by a 2Kx2K HAWAII2-RG detector with a pixel size of 18.5 {mu}mx18.5 {mu}m, resulting 0.95x0.95 deg{sup 2} field of view with an image scale of 1.6 arcsec/pixel. OAOWFC is designed to be a fully robotic instrument. This camera forms a part of Multicolor Imaging Telescopes for Survey and Monstrous Explosions (MITSuME), a multi telescope system dedicated to optical-NIR follow-up observations of GRB afterglows. Very wide field of view of OAOWFC enables us to catch GRB afterglows under less accurate localization sometimes given by the first alert. OAOWFC has an ability to detect bright GRB afterglow located at z = 10 easily, and it might be detectable at z = 18 if the conditions are met.

Yoshida, M.; Yanagisawa, K.; Shimizu, Y.; Okita, K.; Nagayama, S.; Toda, H. [Okayama Astrophysical Observatory, Kamogata, Okayama 719-0232 (Japan); Ohta, K. [Department of Astronomy Kyoto University, Kyoto 606-8502 (Japan); Kawai, N. [Department of Physics, Tokyo Institute of Technology, Meguro-ku, Tokyo 152-8551 (Japan)

2008-05-22

96

Optical MEMS: past, present and future  

NASA Astrophysics Data System (ADS)

Spurred by the growth of the internet, Optical Telecommunications bandwidth, experienced unprecedented growth during late 1990's. During this time of great economic expansion, the creation of new enterprises was vast and the expansion of established component, system and services companies was breathtaking. Unfortunately, this positive economic state was short-lived. This period was followed in 2001-2004 by one of the most significant market crashes in history. During those 10 years of economic growth, about $20B in venture capital was invested in the optical telecom industry, most of this investment was lost in recent years. Many start-up industries which experienced unprecedented growth at the end of the 20th century were lost at the start of the 21st. (1) During this time many, innovative technologies were born and buried. However, many new capabilities emerged from this period of unrest; one such example is the advent of Optical MEMS (MOEMS). Many academics and corporate laboratories pursued the development of MOEMS during the economic boom and, in the author's view; MOEMS surfaced as a powerful and versatile tool set that has proved invaluable and in the last few years during economic downturn, stood the test of time. In the Telecommunications industry, for optical switching and wavelength management applications MOEMS has proven to be the technology of choice. (2) Variable Optical Attenuators (VOA), Wavelength Blockers (WB), Dynamic Gain Equalizers (DGE), and most recently Wavelength Selective Switches (WSS) are being used in the numerous recent network deployments. Moreover, agile networks of the future will have MOEMS at every node. This presentation will provide an overview of the history of MOEMS in Telecommunications, discuss its byproducts and offer a window into the future of the technology.

Ramani, Chandra Mouli

2005-09-01

97

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

98

Deployment of the Hobby-Eberly Telescope wide field upgrade  

NASA Astrophysics Data System (ADS)

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

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

2014-07-01

99

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

100

WISH: wide-field imaging surveyor at high redshift  

NASA Astrophysics Data System (ADS)

WISH is a new space science mission concept whose primary goal is to study the first galaxies in the early universe. We will launch a 1.5m telescope equipped with 1000 arcmin2 wide-field NIR camera by late 2010's in order to conduct unique ultra-deep and wide-area sky surveys at 1-5 micron. The primary science goal of WISH mission is pushing the high-redshift frontier beyond the epoch of reionization by utilizing its unique imaging capability and the dedicated survey strategy. We expect to detect ~104 galaxies at z=8-9, ~3-6x103 galaxies at z=11-12, and ~50-100 galaxies at z=14-17 within about 5 years of the planned mission life time. It is worth mentioning that a large fraction of these objects may be bright enough for the spectroscopic observations with the extremely large telescopes. By adopting the optimized strategy for the recurrent observations to reach the depth, we also use the surveys to detect transient objects. Type Ia Supernova cosmology is thus another important primary goal of WISH. A unique optical layout has been developed to achieve the diffraction-limited imaging at 1-5micron over the required large area. Cooling the mirror and telescope to ~100K is needed to achieve the zodiacal light limited imaging and WISH will achieve the required temperature by passive cooling in the stable thermal environment at the orbit near Sun-Earth L2. We are conducting the conceptual studies and development for the important components of WISH including the exchange mechanism for the wide-field filters as well as the primary mirror fixation.

Yamada, Toru; Doi, Mamoru; Goto, Tomotsugu; Ikeda, Yuji; Imanishi, Masatoshi; Inoue, Akio; Iwamura, Satoru; Iwata, Ikuru; Kawai, Nobuyuki; Kobayashi, Masakazu A. R.; Kodama, Tadayuki; Komiyama, Yutaka; Matsuhara, Hideo; Matsuoka, Yoshiki; Morokuma, Tomoki; Ohta, Kouji; Oyabu, Shinki; Sato, Yoichi; Sugita, Hiroyuki; Tsutsui, Ryo; Tokoku, Chihiro; Tsuneta, Saku; Wada, Takehiko; Yabe, Kiyoto; Yasuda, Naoki; Yonetoku, Daisuke

2010-07-01

101

The photometric system of the Nanshan One-meter Wide field Telescope  

NASA Astrophysics Data System (ADS)

A one-meter wide field astronomical telescope with Alt-Az mount, putting in work at prime focus with field corrector, is located at the Nanshan site of Xinjiang Astronomical Observatory. The Nanshan One meter Wide-field Telescope (hereafter NOWT) provides excellent optical quality, pointing accuracy and tracking accuracy. The main scientific goals of NOWT are supernovae, gamma-ray bursts, novae, variable stars, and active galactic nuclei. It is worthwhile to point out that the sky background at the Nanshan is a classic optical site.

Liu, Jinzhong; Zhang, Yu; Feng, Guojie; Bai, Chunhai

2014-01-01

102

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

103

Optical processing for future computer networks  

NASA Technical Reports Server (NTRS)

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

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

1986-01-01

104

Toward future IP optical backbone networks  

NASA Astrophysics Data System (ADS)

The rapid and aggressive penetration of broadband access services such as fiber to the home (FTTH) has been accelerating the increase in IP traffic volume and new networking technologies are required in order to accommodate future traffic in a cost-effective manner. This paper overviews the advanced IP optical network architecture and technologies for very-large-scale IP backbone networks. These technologies are the key to accommodate the huge volumes of IP traffic expected and control network resources in an effective and dynamic manner. We describe advanced IP optical networking technologies which accommodate multiple service networks using multi-instance technologies, and enable multi-layer traffic engineering using virtual network topology technologies. The migration scenario is described from the existing networks to GMPLS networks; reference is made to the advanced Path Computation Element (PCE) which enables multi-layer traffic engineering and MPLS/GMPLS migration. New network concepts such as Layer 1 Virtual Private Network (L1VPN) and GMPLS interoperability issues, which are being discussed in IETF, are also described.

Urushidani, Shigeo

2005-11-01

105

Wide field x-ray surveys: wide field x-ray telescope (WFXT) and notional wide field imager (N-WFI)  

NASA Astrophysics Data System (ADS)

Wide field X-ray surveys require large field of view telescopes operating in a step and repeat or slow scanning mode in order to cover large areas of the sky efficiently. Here we discuss two similar, yet different designs for a wide field survey mission that can each be accomplished for a cost of less than $1B (FY 2012) and that cover many hundreds to several thousand deg2, with medium depth few × 10-16 erg s-1cm2, and several 10’s of degrees with very long exposure time to a depth approaching 3 × 10-17 erg s-1cm2. We review the WFXT design and compare it with the Notional Wide Field Imager (N-WFI) concept that was developed by the NASA CST in response to a charge from NASA to define generic (or notional) missions that can accomplish some (or all) of the IXO science, but at a reduced cost.

Murray, Stephen S.

2012-09-01

106

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

Microsoft Academic Search

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

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

2008-01-01

107

Experimental validation of wide-field integration methods for autonomous navigation  

Microsoft Academic Search

Wide-field integration (WFI) methods, which are based on the spatial decompositions of optic flow performed by motion sensitive tangential neurons within the insect visuomotor system, have been shown to be an efficient and robust way to extract visual cues for guidance and navigation. In this paper, previous analytical results on WFI-based autonomous local guidance are validated on a wheeled robotic

James Sean Humbert; Andrew Maxwell Hyslop; Michael Chinn

2007-01-01

108

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 of the Earth). The detrimental effects of solar storm induced "space weather" ranges from disruption of our. The National Oceanic & Atmospheric Administration (NOAA) and NASA are cooperating on a Solar X-ray Imager (SXI

Van Stryland, Eric

109

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

110

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

111

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

112

The wide field upgrade for the Hobby-Eberly Telescope John A. Booth*a  

E-print Network

as it is modified to support the HET Dark Energy Experiment (HETDEX), current, and future instrumentation. HETDEX: · The Wide Field Corrector (WFC) · The new Prime Focus Instrument Package (PFIP) · The new Tracker. The new Prime Focus Instrument Package (PFIP), described in Section 5, serves as a mount and interface

113

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

114

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

NASA Technical Reports Server (NTRS)

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

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

2006-01-01

115

Exploiting speckle correlations to improve the resolution of wide-field fluorescence microscopy  

E-print Network

Fluorescence microscopy is indispensable in nanoscience and biological sciences. The versatility of labeling target structures with fluorescent dyes permits to visualize structure and function at a subcellular resolution with a wide field of view. Due to the diffraction limit, conventional optical microscopes are limited to resolving structures larger than 200 nm. The resolution can be enhanced by near-field and far-field super-resolution microscopy methods. Near-field methods typically have a limited field of view and far-field methods are limited by the involved conventional optics. Here, we introduce a combined high-resolution and wide-field fluorescence microscopy method that improves the resolution of a conventional optical microscope by exploiting correlations in speckle illumination through a randomly scattering high-index medium: Speckle correlation resolution enhancement (SCORE). As a test, we collect two-dimensional fluorescence images of 100-nm diameter dye-doped nanospheres. We demonstrate a decon...

Yilmaz, Hasan; Bertolotti, Jacopo; Lagendijk, Ad; Vos, Willem L; Mosk, Allard P

2014-01-01

116

IAU Working Group on Wide-Field Imaging.  

NASA Astrophysics Data System (ADS)

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

MacGillivray, H. T.

1991-01-01

117

Deep-Space Optical Communications: Future  

E-print Network

-space optical communica- tions was formulated shortly after the invention of lasers. The promise of laser progression of increasing radio-frequency (RF) bands (S, X, and Ka) that can be efficiently transmitted

Djordjevic, Ivan B.

118

Artist's Concept of Wide-field Infrared Survey Explorer (WISE)  

NASA Technical Reports Server (NTRS)

Artist's concept of Wide-field Infrared Survey Explorer.

A new NASA mission will scan the entire sky in infrared light in search of nearby cool stars, planetary construction zones and the brightest galaxies in the universe.

Called the Wide-field Infrared Survey Explorer, the mission has been approved to proceed into the preliminary design phase as the next in NASA's Medium-class Explorer program of lower cost, highly focused, rapid-development scientific spacecraft. It is scheduled to launch in 2008.

2004-01-01

119

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

120

The Multiplexed Imaging Method: High-Resolution Wide Field Imaging Using Physically Small Detectors  

NASA Astrophysics Data System (ADS)

We present the method of multiplexed imaging designed for astronomical observations of large sky areas in the IR, visible, and UV frequencies. Our method relies on the sparse nature of astronomical observations. The method consists of an optical system that directs light from different locations on the focal plane of a telescope onto the same detector area and an algorithm that reconstructs the original wide-field image. In this way we can use a physically small detector to cover a wide field of view. We test our reconstruction algorithm using public space telescope data. Our tests demonstrate the reliability and power of the multiplexed imaging method. Using our method it will be possible to increase the sky area covered with space telescopes by 1--3 orders of magnitude, depending on the specific scientific goal and optical parameters. This method can significantly increase the volume of astronomical surveys, including search programs for exoplanets and transients using space and ground instruments.

Zackay, Barak; Gal-Yam, Avishay

2014-02-01

121

Wide-field Imaging Interferometry Testbed II: Implementation, Performance, and Plans  

E-print Network

The Wide-Field Imaging Interferometry Testbed (WIIT) will provide valuable information for the development of space-based interferometers. This laboratory instrument operates at optical wavelengths and provides the ability to test operational algorithms and techniques for data reduction of interferometric data. Here we present some details of the system design and implementation, discuss the overall performance of the system to date, and present our plans for future development of WIIT. In order to make best use of the interferometric data obtained with this system, it is critical to limit uncertainties within the system and to accurately understand possible sources of error. The WIIT design addresses these criteria through a number of ancillary systems. The use of redundant metrology systems is one of the most important features of WIIT, and provides knowledge of the delay line position to better than 10 nm. A light power detector is used to monitor the brightness of our light sources to ensure that small fluctuations in brightness do not affect overall performance. We have placed temperature sensors on critical components of the instrument, and on the optical table, in order to assess environmental effects on the system. The use of these systems provides us with estimates of the overall system uncertainty, and allows an overall characterization of the results to date. These estimates allow us to proceed forward with WIIT, adding rotation stages for 2-D interferometry. In addition, they suggest possible avenues for system improvement. Funding for WIIT is provided by NASA Headquarters through the ROSS/SARA Program and by the Goddard Space Flight Center through the IR&D Program.

S. A. Rinehart; Bradley J. Frey; David T. Leisawitz; Douglas B. Leviton; Anthony J. Martino; William L. Maynard; Lee G. Mundy; Stacy H. Teng; Xiaolei Zhang

2002-11-07

122

Architectural and technological issues for future optical Internet networks  

Microsoft Academic Search

This article reports a review of the most significant issues related to network architectures and technologies which will enable the realization of future optical Internet networks. The design of such networks has to take into consideration the peculiar characteristics of Internet traffic. Several architectures have been proposed to provide optical networking solutions, based on wavelength-division multiplexing and compatible with the

M. Listanti; V. Eramo; R. Sabella

2000-01-01

123

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

124

PyWiFeS: Wide Field Spectrograph data reduction pipeline  

NASA Astrophysics Data System (ADS)

PyWiFeS is a Python-based data reduction pipeline for the Wide Field Spectrograph (WiFeS). Its core data processing routines are built on standard scientific Python packages commonly used in astronomical applications. It includes an implementation of a global optical model of the spectrograph which provides wavelengths solutions accurate to ˜0.05 Å (RMS) across the entire detector. Through scripting, PyWiFeS can enable batch processing of large quantities of data.

Childress, Michael; Vogt, Frédéric; Nielsen, Jon; Sharp, Rob

2014-02-01

125

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

126

Wide-field interferometric phase microscopy with molecular specificity using plasmonic nanoparticles.  

PubMed

We present a method for adding molecular specificity to wide-field interferometric phase microscopy (IPM) by recording the phase signatures of gold nanoparticles (AuNPs) labeling targets of interest in biological cells. The AuNPs are excited by time-modulated light at a wavelength corresponding to their absorption spectral peak, evoking a photothermal (PT) effect due to their plasmonic resonance. This effect induces a local temperature rise, resulting in local refractive index and phase changes that can be detected optically. Using a wide-field interferometric phase microscope, we acquired an image sequence of the AuNP sample phase profile without requiring lateral scanning, and analyzed the time-dependent profile of the entire field of view using a Fourier analysis, creating a map of the locations of AuNPs in the sample. The system can image a wide-field PT phase signal from a cluster containing down to 16 isolated AuNPs. AuNPs are then conjugated to epidermal growth factor receptor (EGFR) antibodies and inserted to an EGFR-overexpressing cancer cell culture, which is imaged using IPM and verified by confocal microscopy. To the best of our knowledge, this is the first time wide-field interferometric PT imaging is performed at the subcellular level without the need for total internal reflection effects or scanning. PMID:24081309

Turko, Nir A; Peled, Anna; Shaked, Natan T

2013-11-01

127

Si photonics technology for future optical interconnection  

NASA Astrophysics Data System (ADS)

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

Zheng, Xuezhe; Krishnamoorthy, Ashok V.

2011-12-01

128

Wide-field camera 3 ground testing and calibration  

Microsoft Academic Search

Wide Field Camera 3 (WFC3), a panchromatic imager being developed for the Hubble Space Telescope (HST), is now fully integrated and has undergone extensive ground testing at Goddard Space Flight Center, in both ambient and thermal-vacuum test environments. The thermal-vacuum testing marks the first time that both of the WFC3 UV\\/Visible and IR channels have been operated and characterized in

H. Bushouse; S. Baggett; T. Brown; G. F. Hartig; B. Hilbert; R. J. Hill; R. A. Kimble; O. Lupie; J. W. MacKenty; I. N. Reid; M. Robberto

2006-01-01

129

WINGS: a Wide-field Imaging Nearby Galaxy clusters Survey  

NASA Astrophysics Data System (ADS)

We present a two-band, wide-field imaging survey of an X-ray selected sample of 78 clusters in the redshift range z=0.03-0.07. The aim of the project is to provide the astronomical community with a complete set of homogeneous, CCD-based, surface photometry and morphological data of the nearby cluster galaxies located within 1.5Mpc from the cluster center.

Fasano, G.; Bettoni, D.; Marmo, C.; Pignatelli, E.; Poggianti, B. M.; Moles, M.; Kjærgaard, P.

130

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

131

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

132

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

NASA Astrophysics Data System (ADS)

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

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

2010-02-01

133

Optical interferometry in Antarctica: a future for European astronomy?  

Microsoft Academic Search

During the next decade, the European Very Large Telescope Interferometer (vlti) will remain one of the most productive existing optical interferometers. Costly space missions will not soon provide new steps in sensitivity, imaging capability and higher resolution. Hence, although they represent the long term future, it is wise for groud-based interferometry to look beyond the horizon 2020 and to prepare

P. Léna

2010-01-01

134

The JPL Optical Communications Telescope Laboratory Test Bed for the Future Optical Deep Space Network  

Microsoft Academic Search

The lower power consumption and lower mass of high-bandwidth optical telecom- munications relative to RF telecommunications make laser communication technol- ogy extremely attractive for returning data from future NASA\\/JPL deep-space probes. JPL is building a research and development optical communications tele- scope laboratory (OCTL) at its Table Mountain Facility in Southern California to evaluate strategies for supporting operations from future

K. E. Wilson; N. Page; J. Wu; M. Srinivasan

2003-01-01

135

Observing GRBs with the LOFT Wide Field Monitor  

NASA Astrophysics Data System (ADS)

LOFT (Large Observatory For X-ray Timing) is one of the four candidate missions currently under assessment study for the M3 mission in ESAs Cosmic Vision program to be launched in 2024. LOFT will carry two instruments with prime sensitivity in the 2-30 keV range: a 10 m2 class large area detector (LAD) with a <1° collimated field of view and a wide field monitor (WFM) instrument. The WFM is based on the coded mask principle, and 5 camera units will provide coverage of more than 1/3 of the sky. The prime goal of the WFM is to detect transient sources to be observed by the LAD. With its wide field of view and good energy resolution of <500 eV, the WFM will be an excellent instrument for detecting and studying GRBs and X-ray flashes. The WFM will be able to detect ~150 gamma ray bursts per year, and a burst alert system will enable the distribution of ~100 GRB positions per year with a ~1 arcmin location accuracy within 30 s of the burst.

Brandt, S.; Hernanz, M.; Feroci, M.; Amati, L.; Alvarez; Azzarello, P.; Barret, D.; Bozzo, E.; Budtz-Jørgensen, C.; Campana, R.; Castro-Tirado, A.; Cros, A.; Del Monte, E.; Donnarumma, I.; Evangelista, Y.; Galvez Sanchez, J. L.; Götz, D.; Hansen, F.; den Herder, J. W.; Hornstrup, A.; Hudec, R.; Karelin, D.; van der Klis, M.; Korpela, S.; Kuvvetli, I.; Lund, N.; Orleanski, P.; Pohl, M.; Rachevski, A.; Santangelo, A.; Schanne, S.; Schmid, C.; Stella, L.; Suchy, S.; Tenzer, C.; Vacchi, A.; Wilms, J.; Zampa, N.; in't Zand, J. J. M.; Zdziarski, A.

2013-07-01

136

MOSFIRE: a multi-object near-infrared spectrograph and wide-field camera for the Keck Observatory  

E-print Network

MOSFIRE: a multi-object near-infrared spectrograph and wide-field camera for the Keck Observatory of California/Santa Cruz, Santa Cruz, CA USA 95064 d W. M. Keck Observatory, 65-1120 Mamalahoa Highway, Kamuela of the third generation instrument program at the W. M. Keck Observatory (WMKO)1 . The optical design provides

Steidel, Chuck

137

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

138

Dwarf Irregular Galaxy Leo A: Suprime-Cam Wide-field Stellar Photometry  

NASA Astrophysics Data System (ADS)

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

Stonkut?, Rima; Arimoto, Nobuo; Hasegawa, Takashi; Narbutis, Donatas; Tamura, Naoyuki; Vansevi?ius, Vladas

2014-10-01

139

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

140

A Parallel Imaging Approach to Wide-field MR Microscopy  

PubMed Central

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

McDougall, Mary Preston; Wright, Steven M.

2011-01-01

141

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

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

Optical interferometry in Antarctica: a future for European astronomy?  

NASA Astrophysics Data System (ADS)

During the next decade, the European Very Large Telescope Interferometer (vlti) will remain one of the most productive existing optical interferometers. Costly space missions will not soon provide new steps in sensitivity, imaging capability and higher resolution. Hence, although they represent the long term future, it is wise for groud-based interferometry to look beyond the horizon 2020 and to prepare for it, even if large projects mobilize today nearly all available European resources. The context of the vlti decision, the situation in optical interferometry today and the critical role of site seeing for performances are recalled. Given what is known of Antarctica sites, it appears relevant to pursue their study for interferometric use. Possible steps may be within the European Southern Observatory for seeing studies and independently at Concordia with a modest interferometer (e.g. alladin). It may pave the way for the future of interferometry, to be decided in a decade or so.

Léna, P.

144

Including detector effects in the design of wide-field imaging systems  

NASA Astrophysics Data System (ADS)

Most imaging systems today include a mosaic detector array in the focal plane. Optical designers of astronomical telescopes typically produce a design that yields a superb on-axis aerial image in the focal plane, and detector effects are included only in the analysis of the final system performance. Aplanatic optical designs (corrected for spherical aberration and coma) are widely considered to be superior to non-aplanatic designs. However, there is little merit in an aplanatic design for wide field applications because one needs to optimize some-field-weighted average measure of resolution over the desired operational field of-view (OFOV). Furthermore, when used with a mosaic detector array in the focal plane, detector effects eliminate the advantage of the aplanatic design even at small field angles. For wide fields of view, the focal plane is frequently despaced to balance field curvature with defocus thus obtaining better overall performance. We will demonstrate that including detector effects in the design process results in a different optimal (non-aplanatic) design for each OFOV that is even superior to an optimally despaced aplanatic design.

Harvey, James E.; Atanassova, Martina; Krywonos, Andrey

2004-10-01

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

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

147

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

148

Classifying civilian vehicles using a wide-field circular SAR  

NASA Astrophysics Data System (ADS)

In this paper we consider classification of civilian vehicles using circular synthetic aperture radar. For wide-field application in which the scene radius is a significant fraction of the flight path radius, vehicle signatures are spatially variant due to layover. For a ten-class identification task using simulated X-band signatures, we demonstrate 96% correct classification for single-pass 2D imagery with scene radius 0.4 times the flight radius. Simulated scattering data include multi-path and material effects. Image signatures are represented by sets of attributed scattering centers. Dissimilarity between attributed point sets is computed via a minimized partial Hausdorff distance. Using multidimensional scaling, the distances are represented in a low-dimensional Euclidean space for both visualization and improved classification. The minimized partial Hausdorff distance, while not a true distance, empirically shows remarkable fidelity to the triangle inequality. Finally, in a limited two-class study, we show that three-dimensional imaging of layover points using polarization cues provides improved class separability.

Dungan, Kerry E.; Potter, Lee C.

2009-05-01

149

Status and Calibration of the HST Wide Field Camera 3  

NASA Astrophysics Data System (ADS)

We report on the current status and calibration of the Hubble Space Telescope's Wide Field Camera 3. This UV, Visible, near Infrared Camera was installed in 2009 during HST Servicing Mission 4 and has proven to be the most used instrument on the observatory. Recent improvements in its photometric, flat field, dark current, and astrometric calibrations are discussed. As WFC3 approaches the mid-point of its 4th year of operation in space, the impacts of the space environment are presented with particular attention to the consequences of radiation damage on the performance of the CCD detectors. Recent improvements in operational strategies including post-flashing CCD observations are discussed together with recommendations for acquiring optimal observations and methods of improving data analysis. We also high-light recent progress in using observatory level spatial scans to achieve higher dynamic range observations, to obtain higher precision and more efficient photometric measurements of bright sources, to improve our knowledge of the flat fields, and to increase the precision of astrometric measurements.

MacKenty, John W.; WFC3

2013-01-01

150

Instrumental and scientific simulations of the LOFT Wide Field Monitor  

E-print Network

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; Campana, R; Schmid, C; Feroci, M

2014-01-01

151

The design of the wide field monitor for LOFT  

E-print Network

LOFT (Large Observatory For x-ray Timing) is one of the ESA M3 missions selected within the Cosmic Vision program in 2011 to carry out an assessment phase study and compete for a launch opportunity in 2022-2024. The phase-A studies of all M3 missions were completed at the end of 2013. LOFT is designed to carry on-board two instruments with sensitivity in the 2-50 keV range: a 10 m 2 class Large Area Detector (LAD) with a transient sources to be observed by the LAD. However, thanks to its unique combination of a wide field of view (FoV) and energy resolution (better than 500 eV), the WFM will be also an excellent monitoring instrument to study the long term variability of many classes of X-ray sources. The WFM consists of 10 independent and identical coded mask cameras arranged in 5 pairs to provide the desired sky c...

Brandt, S; Alvarez, L; Argan, A; Artigues, B; Azzarello, P; Barret, D; Bozzo, E; Budtz-Jørgensen,; Campana, R; Cros, A; del Monte, E; Donnarumma, I; Evangelista, Y; Feroci, M; Sanchez, J L Galvez; Götz, D; Hansen, F; Herder, J W den; Hudec, R; Huovelin, J; Karelin, D; Korpela, S; Lund, N; Michalska, M; Olsen, P; Orleanski, P; Pedersen, S; Pohl, M; Rachevski, A; Santangelo, A; Schanne, S; Schmid, C; Suchy, S; Tenzer, C; Vacchi, A; Walton, D; Wilms, J; Zampa, G; Zampa, N; Zand, J int; Zane, S; Zdziarski, A; Zwart, F

2014-01-01

152

Integration of wide field-of-view imagery functions in a detector dewar cooler assembly  

NASA Astrophysics Data System (ADS)

Today, both military and civilian applications require miniaturized optical systems in order to give an imagery function to vehicles with small payload capacity. After the development of megapixel focal plane arrays (FPA) with micro-sized pixels, this miniaturization will become feasible with the integration of optical functions in the detector area. In the field of cooled infrared imaging systems, the detector area is the Detector-Dewar-Cooler Assembly (DDCA). A dewar is a sealed environment where the detector is cooled on a cold plate. We show in this paper that wide field of view imagery functions can be simply added to the dewar. We investigate two ways of integration and make two demonstrators. The first one called FISBI consists in replacing the window by a fish-eye lens and in integrating a lens in the cold shield. This optical system has a field of view of 180°. The second one, called IR-Cam-on-Chip, consists in integrating the optics directly on the focal plane array. This optical system has a field of view of 120°. The additional mass of the optics is sufficiently small to be compatible with the cryogenic environment of the DDCA. The performance of these cameras will be discussed and several evolutions of these cameras will be introduced too.

Druart, Guillaume; de la Barriere, Florence; Guerineau, Nicolas; Lasfargues, Gilles; Fendler, Manuel; Lhermet, Nicolas; Taboury, Jean; Reibel, Yann; Moullec, Jean-Baptiste

2012-06-01

153

Making light work: illuminating the future of biomedical optics.  

PubMed

In 1996, the Royal Society held a Discussion Meeting entitled 'Near-infrared spectroscopy and imaging of living systems'. In 2010, this topic was revisited in a Theo Murphy Royal Society Scientific Discussion Meeting entitled 'Making light work: illuminating the future of biomedical optics'. The second meeting provided the opportunity for leading researchers to reflect on how the technology, methods and applications have evolved over the past 14 years and assess where they have made a major impact. Particular emphasis was placed on discussions of future prospects and associated challenges. This Introduction provides an overview of the state of the art of near-infrared spectroscopy (NIRS) and biomedical optics, with specific reference to the contributed papers from the invited speakers included in this issue. Importantly, we also reflect on the contributions from all of the attendees by highlighting the issues raised during oral presentations, facilitated panel sessions and discussions, and use these to summarize the current opinion on the development and application of optical systems for use in the clinical and life sciences. A notable outcome from the meeting was a plan to establish a biennial international conference for developers and users of NIRS technologies. PMID:22006895

Elwell, Clare E; Cooper, Chris E

2011-11-28

154

The Wide-Field Imaging Interferometry Testbed III. Metrology Subsystem  

E-print Network

In order for data products from WIIT to be as robust as possible, the alignment and mechanical positions of source, receiver, and detector components must be controlled and measured with extreme precision and accuracy, and the ambient environment must be monitored to allow environmental effects to be correlated with even small perturbations to fringe data. Relevant detailed anatomy of many testbed components and assemblies are described. The system of displacement measuring interferometers (DMI), optical encoders, optical alignment tools, optical power monitors, and temperature sensors implemented for control and monitoring of the testbed is presented.

D. B. Leviton; B. J. Frey; D. T. Leisawitz; A. J. Martino; W. L. Maynard; L. G. Mundy; S. A. Rinehart; S. H. Teng; X. Zhang

2002-10-01

155

The Wide-Field Imaging Interferometry Testbed III. Metrology Subsystem  

E-print Network

In order for data products from WIIT to be as robust as possible, the alignment and mechanical positions of source, receiver, and detector components must be controlled and measured with extreme precision and accuracy, and the ambient environment must be monitored to allow environmental effects to be correlated with even small perturbations to fringe data. Relevant detailed anatomy of many testbed components and assemblies are described. The system of displacement measuring interferometers (DMI), optical encoders, optical alignment tools, optical power monitors, and temperature sensors implemented for control and monitoring of the testbed is presented.

Leviton, D B; Leisawitz, D T; Martino, A J; Maynard, W L; Mundy, L G; Rinehart, S A; Teng, S H; Zhang, X

2002-01-01

156

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

157

Optical Packet & Circuit Integrated Network for Future Networks  

NASA Astrophysics Data System (ADS)

This paper presents recent progress made in the development of an optical packet and circuit integrated network. From the viewpoint of end users, this is a single network that provides both high-speed, inexpensive services and deterministic-delay, low-data-loss services according to the users' usage scenario. From the viewpoint of network service providers, this network provides large switching capacity with low energy requirements, high flexibility, and efficient resource utilization with a simple control mechanism. The network we describe here will contribute to diversification of services, enhanced functional flexibility, and efficient energy consumption, which are included in the twelve design goals of Future Networks announced by ITU-T (International Telecommunication Union - Telecommunication Standardization Sector). We examine the waveband-based network architecture of the optical packet and circuit integrated network. Use of multi-wavelength optical packet increases the switch throughput while minimizing energy consumption. A rank accounting method provides a solution to the problem of inter-domain signaling for end-to-end lightpath establishment. Moving boundary control for packet and circuit services makes for efficient resource utilization. We also describe related advanced technologies such as waveband switching, elastic lightpaths, automatic locator numbering assignment, and biologically-inspired control of optical integrated network.

Harai, Hiroaki

158

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

159

Characterization of High Proper Motion Objects from the Wide-field Infrared Survey Explorer  

NASA Astrophysics Data System (ADS)

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

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

2014-06-01

160

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

PubMed

We demonstrate the use of a compressive sampling algorithm for on-chip fluorescent imaging of sparse objects over an ultra-large field-of-view (>8 cm(2)) without the need for any lenses or mechanical scanning. In this lensfree imaging technique, fluorescent samples placed on a chip are excited through a prism interface, where the pump light is filtered out by total internal reflection after exciting the entire sample volume. The emitted fluorescent light from the specimen is collected through an on-chip fiber-optic faceplate and is delivered to a wide field-of-view opto-electronic sensor array for lensless recording of fluorescent spots corresponding to the samples. A compressive sampling based optimization algorithm is then used to rapidly reconstruct the sparse distribution of fluorescent sources to achieve approximately 10 microm spatial resolution over the entire active region of the sensor-array, i.e., over an imaging field-of-view of >8 cm(2). Such a wide-field lensless fluorescent imaging platform could especially be significant for high-throughput imaging cytometry, rare cell analysis, as well as for micro-array research. PMID:20588904

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

2010-05-10

161

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

162

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

163

The Hot and Energetic Universe: The Wide Field Imager (WFI) for Athena+  

E-print Network

The Wide Field Imager (WFI) is one of the two scientific instruments proposed for the Athena+ X-ray observatory. It will provide imaging in the 0.1-15 keV band over a wide field, simultaneously with spectrally and time-resolved photon counting. The instrument is designed to make optimal use of the grasp (collecting area times solid angle product) provided by the optical design of the Athena+ mirror system (Willingale et al. 2013), by combining a sensitive approx. 40' diameter field of view (baseline; 50' goal) DEPFET detector with a pixel size properly sampling the angular resolution of 5 arc sec on-axis (half energy width).This synthesis makes the WFI a very powerful survey instrument, significantly surpassing currently existing capabilities (Nandra et al. 2013; Aird et al. 2013). In addition, the WFI will provide unprecedented simultaneous high-time resolution and high count rate capabilities for the observation of bright sources with low pile-up and high efficiency. In this paper, we summarize the instrume...

Rau, A; Nandra, K; Porro, M; Barret, D; Santangelo, A; Schmid, C; Struder, L; Tenzer, C; Wilms, J; Amoros, C; Andritschke, R; Aschauer, F; Bahr, A; Gunther, B; Furmetz, M; Ott, B; Perinati, E; Rambaud, D; Reiffers, J; Treis, J; von Kienlin, A; Weidenspointner, G

2013-01-01

164

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

165

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

166

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

167

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

168

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

169

e-VLBI... a Wide-field Imaging Instrument with milliarcsecond Resolution & microJy Sensitivity  

E-print Network

The European VLBI Network (EVN) is in the process of establishing an e-VLBI array in which the radio telescopes and the EVN correlator at JIVE are connected in real-time, via high-speed national fibre optic networks and the pan-European research network, GEANT. This paper reports on recent test results, including the production of the first real-time e-VLBI astronomical image. In a parallel and related development, the field-of-view of VLBI is also expanding by many orders of magnitude, and the first results of deep, wide-field surveys capable of detecting many sources simultaneously are summarised. The detection of sources as faint as 10 microJy should soon be possible in the era of ``Mk5'' and e-VLBI.

M. A. Garrett

2004-09-01

170

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

171

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

172

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

NASA Technical Reports Server (NTRS)

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

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

1981-01-01

173

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.

174

HARP-B and Wide-Field Imaging of Molecular Clouds  

NASA Astrophysics Data System (ADS)

Molecular clouds within our galaxy provide excellent opportunities to study the processes of star formation in detail. They extend over large regions of the sky, and therefore wide-field imaging is required to capture all of the structure inside them, and to investigate their varied conditions. Performing this task efficiently, in high resolution, and over statistically useful numbers of clouds can best be achieved using array receivers. However these are a relatively new development due to the difficulty of constructing instrumentation for the millimetre and sub-millimetre wavelengths at which molecular clouds emit. Part I of this thesis describes HARP-B - a new heterodyne array receiver operating at 345GHz on the James Clerk Maxwell Telescope. The work described focusses on the optics, interferometer and commissioning of HARP-B. Careful testing and alignment of the optics was necessary to ensure that HARP-B would perform as required. Its Mach-Zehnder interferometer was put under computer control and characterised to allow it to be used as an effective sideband filter. This part concludes with the integration and commissioning of the receiver, leading up to first light. Part II then presents wide-field observations of the IC5146 and L977 molecular clouds, made with HARP-B and other instruments at the JCMT and IRAM 30m telescopes. For IC5146, SCUBA continuum images and a dust extinction map were already available. These were complemented by spectral observations of C18O 1-0, C18O 2-1 and the 3-2 transition of 12CO, 13CO and C18O. The data were used to study the cloud structure, excitation conditions and dust properties. SCUBA continuum and C18O 2-1 observations were made of L977 and analysed along with the existing dust extinction map in order to study the dust and gas properties, and the structure of the molecular cloud.

Bell, Graham S.

2008-10-01

175

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

PubMed Central

Bilateral visual loss secondary to inherited optic neuropathies is an important cause of registrable blindness among children and young adults. The two prototypal disorders seen in clinical practice are Leber hereditary optic neuropathy (LHON) and autosomal dominant optic atrophy (DOA). About 90% of LHON cases are due to one of three mitochondrial DNA (mtDNA) point mutations: m.3460G>A, m.11778G>A, and m.14484T>C, which affect critical complex I subunits of the mitochondrial respiratory chain. The majority of patients with DOA harbour pathogenic mutations within OPA1, a nuclear gene that codes for a multifunctional inner mitochondrial membrane protein. Despite their contrasting genetic basis, LHON and DOA share overlapping pathological and clinical features that serve to highlight the striking tissue-specific vulnerability of the retinal ganglion cell (RGC) layer to disturbed mitochondrial function. In addition to severe visual loss secondary to progressive optic nerve degeneration, a subgroup of patients will also develop a more aggressive syndromic phenotype marked by significant neurological deficits. The management of LHON and DOA remains largely supportive, but major advances in our understanding of the mechanisms underpinning RGC loss in these two disorders are paving the way for novel forms of treatment aimed at halting or reversing visual deterioration at different stages of the disease process. In addition to neuroprotective strategies for rescuing RGCs from irreversible cell death, innovative in vitro fertilisation techniques are providing the tantalising prospect of preventing the germline transmission of pathogenic mtDNA mutations, eradicating in so doing the risk of disease in future generations. PMID:24603424

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

2014-01-01

176

Engineering a highly segmented very wide-field spectrograph  

NASA Astrophysics Data System (ADS)

The concept of segmenting the focal plane of an existing 8m class telescope in order to fill it with an array of several fast cameras has been developed further and in this work the status of an engineering program aimed to produce a design qualified for the construction, and to assess its cost estimates is presented. The original concept of just having simple cameras with all identical optical components other than a pupil plane corrector to remove the fixed aberrations at the off-axis field of a telescope has been extended to introduce a spectroscopic capability and to assess a trade-off between a very large number (of the order of thousand) of cameras with a small single Field of View with a smaller number of cameras able to compensate the aberration on a much larger Field of View with a combination of different optical elements and different ways to mount and align them. The scientific target of a few thousands multi-slit spectra over a Field of View of a few square degrees, combined with the ambition to mount this on an existing 8m class telescope makes the scientific rationale of such an instrument a very interesting one. In the paper we describe the different options for a possible optical design, the trade off between variations on the theme of the large segmentation and we describe briefly the way this kind of instrument can handle a multi-slit configuration. Finally, the feasibility of the components and a brief description of how the cost analysis is being performed are given. Perspectives on the construction of this spectrograph are given as well.

Ragazzoni, R.; Fontana, A.; Maccagni, D.; Baruffolo, A.; Bianco, A. G.; diPaola, A.; Farinato, J.; Gentile, G.; Giallongo, E.; Pedichini, F.; Speziali, R.; Testa, V.

2010-07-01

177

Characterization, testing, and operation of Omega2000 wide-field infrared camera  

NASA Astrophysics Data System (ADS)

Omega2000 is the first near infrared (NIR) wide field camera installed on the 3.5 m telescope at Calar Alto which operates with a 2kx2k HAWAII-2 FPA. Each component of the camera system must suit high requirements to exploit the facilities provided by the imaging sensor. To meet these requirements was a great challenge in design and realization of the optics, the mechanical part and the electronics. The cryogenic optical system with a warm mirror baffle can produce excellent optical quality and high sensitivity over the whole 15.4x15.4 arcmin field of view. The readout electronics together with the camera control software provide multi functional data acquisition and the camera control software can perform the readout and on-line data reduction simultaneously at a high data rate. Different operational and readout modes of the data acquisition of the detector both for engineering and scientific purpose were implemented, tested and optimized and the characteristics of three HAWAII-2 detectors were also determined in their hardware and software environment. Initial astronomical observations were carried out successfully in autumn 2003.

Kovács, Zoltán; Mall, Ulrich; Bizenberger, Peter; Baumeister, Harald; Röser, Hermann-Josef

2004-09-01

178

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

179

Future electro-optical sensors and processing in urban operations  

NASA Astrophysics Data System (ADS)

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

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

2013-10-01

180

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

181

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

182

Finding AGN with wide-field VLBI observations  

E-print Network

VLBI observations are a reliable method to identify AGN, since they require high brightness temperatures for a detection to be made. However, because of the tiny fields of view it is unpractical to carry out VLBI observations of many sources using conventional methods. We used an extension of the DiFX software correlator to image with high sensitivity 96 sources in the Chandra Deep Field South, using only 9h of observing time with the VLBA. We detected 20 sources, 8 of which had not been identified as AGN at any other wavelength, despite the comprehensive coverage of this field. The lack of X-ray counterparts to 1/3 of the VLBI-detected sources, despite the sensitivity of co-located X-ray data, demonstrates that X-ray observations cannot be solely relied upon when searching for AGN activity. Surprisingly, we find that sources classified as type 1 QSOs using X-ray data are always detected, in contrast to the 10% radio-loud objects which are found in optically-selected QSOs. We present the continuation of this ...

Middelberg, Enno; Morgan, John; Rottmann, Helge; Alef, Walter; Tingay, Steven; Norris, Ray; Bach, Uwe; Brisken, Walter; Lenc, Emil

2010-01-01

183

Wide-field Corrector for a Gregory Telescope  

E-print Network

A form of prime focus corrector for the Gregory system is proposed that provides the sub-arcsecond field of view up to 3 degrees in diameter for the spectral range 0.35-0.90 microns. The corrector includes five lenses made of same glass (fused silica is preferable). The distinctive feature of the corrector consists in dissimilar use of the central and edge zones of a front lens disposed in the exit pupil of a two-mirror system. As an example, the f/1.9 telescope is considered with the 6.5-m aperture and the total length 8.8~m. Its primary and secondary mirrors are pure ellipsoids close to concave paraboloid and concave sphere, respectively. In the basic configuration, all surfaces of the corrector are spherical. The diameter of a star image D_{80} varies from 0''.25 on the optical axis up to 0''.50 at the edge of the 2.3-deg field. Only slightly worse images shows spherical corrector for the 2.4-deg field of view. The fraction of vignetted rays grows on 1.7% from the center of field to its edges. Aspherizatio...

Terebizh, V Y

2006-01-01

184

Wide-field Corrector for a Gregory Telescope  

E-print Network

A form of prime focus corrector for the Gregory system is proposed that provides the sub-arcsecond field of view up to 3 degrees in diameter for the spectral range 0.35-0.90 microns. The corrector includes five lenses made of same glass (fused silica is preferable). The distinctive feature of the corrector consists in dissimilar use of the central and edge zones of a front lens disposed in the exit pupil of a two-mirror system. As an example, the f/1.9 telescope is considered with the 6.5-m aperture and the total length 8.8~m. Its primary and secondary mirrors are pure ellipsoids close to concave paraboloid and concave sphere, respectively. In the basic configuration, all surfaces of the corrector are spherical. The diameter of a star image D_{80} varies from 0''.25 on the optical axis up to 0''.50 at the edge of the 2.3-deg field. Only slightly worse images shows spherical corrector for the 2.4-deg field of view. The fraction of vignetted rays grows on 1.7% from the center of field to its edges. Aspherization of some lens surfaces allows to reach sub-arcsecond images in the field of 3.0 in diameter.

V. Yu. Terebizh

2006-05-15

185

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

186

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

NASA Technical Reports Server (NTRS)

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

Collins, Nick

2009-01-01

187

BLIND DECONVOLUTION OF 3D DATA IN WIDE FIELD FLUORESCENCE MICROSCOPY Ferreol Soulez1  

E-print Network

illumination. On the resulting 2D image, structures are more or less defocalized according to their distanceBLIND DECONVOLUTION OF 3D DATA IN WIDE FIELD FLUORESCENCE MICROSCOPY Ferr´eol Soulez1 , Lo¨ic Denis for wide field fluorescence microscopy. The 3D PSF is modeled after a parametrized pupil function. The PSF

Boyer, Edmond

188

A Wide-Field Infrared Camera for the Palomar 200-inch Telescope  

E-print Network

A Wide-Field Infrared Camera for the Palomar 200-inch Telescope J. C. Wilsona, S. S. Eikenberrya, C of both large aperture telescopes and large format near-infrared (NIR) detectors are making wide-field NIR that provides the Palomar 200-inch telescope with such an imaging capability. WIRC features a field-of-view (FOV

Galis, Frietson

189

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

E-print Network

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 8m 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 2.2m with HAWK-I observations. We showed that we are able to achi...

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

2014-01-01

190

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

191

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

192

Brca1\\/p53 deficient mouse breast tumor hemodynamics during hyperoxic respiratory challenge monitored by a novel wide-field functional imaging (WiFI) system  

Microsoft Academic Search

Current imaging modalities allow precise visualization of tumors but do not enable quantitative characterization of the tumor metabolic state. Such quantitative information would enhance our understanding of tumor progression and response to treatment, and to our overall understanding of tumor biology. To address this problem, we have developed a wide-field functional imaging (WiFI) instrument which combines two optical imaging modalities,

Austin Moy; Jae G. Kim; Eva Y. H. P. Lee; Bruce Tromberg; Albert Cerussi; Bernard Choi

2009-01-01

193

Wide-field Multiband Photometry of Globular Cluster Systems in the Fornax Galaxy Cluster  

NASA Astrophysics Data System (ADS)

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 0 ~ 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 ~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; Sohn, Sangmo Tony; Kim, Sang Chul; Kim, Eunhyeuk; Chung, Chul; Lee, Sang-Yoon; Lee, Young-Wook

2013-01-01

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

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

NASA Technical Reports Server (NTRS)

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

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

1993-01-01

196

Preliminary Design of The Wide-Field Infrared Survey Explorer (WISE)  

E-print Network

The Wide-field Infrared Survey Explorer (WISE), a NASA MIDEX mission, will survey the entire sky in four bands from 3.3 to 23 microns with a sensitivity 1000 times greater than the IRAS survey. The WISE survey will extend the Two Micron All Sky Survey into the thermal infrared and will provide an important catalog for the James Webb Space Telescope. Using 1024x1024 HgCdTe and Si:As arrays at 3.3, 4.7, 12 and 23 microns, WISE will find the most luminous galaxies in the universe, the closest stars to the Sun, and it will detect most of the main belt asteroids larger than 3 km. The single WISE instrument consists of a 40 cm diamond-turned aluminum afocal telescope, a two-stage solid hydrogen cryostat, a scan mirror mechanism, and reimaging optics giving 5" resolution (full-width-half-maximum). The use of dichroics and beamsplitters allows four color images of a 47'x47' field of view to be taken every 8.8 seconds, synchronized with the orbital motion to provide total sky coverage with overlap between revolutions....

Mainzer, A K; Wright, E L; Liu, F; Irace, W; Heinrichsen, I; Cutri, R; Duval, V

2005-01-01

197

[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

198

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

199

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

200

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 < V_Hel<+6500 km/s. The primary data consists of auto-correlation spectra with an effective angular resolution of 49' FWHM. We detect 155 external galaxies in excess of 8 sigma in integrated HI flux density. Plausible optical associations are found within a 30' search radius for all but one of our HI detections in DSS images, although several are not previously cataloged or do not have published red-shift determinations. Twenty-three of our objects are detected in HI 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. We identify a handful of instances of significant positional offsets exceeding 10 kpc of unconfused optical galaxies with the associated HI centroid, possibly indicative of severe tidal distortions or uncataloged gas-rich companions. A possible trend is found for an excess of detected HI 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 HI 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.

Robert Braun; David Thilker; Rene Walterbos

2003-05-21

201

Wide Field Super-Resolution Surface Imaging through Plasmonic Structured Illumination Microscopy  

E-print Network

Wide Field Super-Resolution Surface Imaging through Plasmonic Structured Illumination Microscopy-resolution imaging technique, plasmonic structured illumination microscopy (PSIM), by combining tunable SP interference (SPI) with structured illumination microscopy (SIM). By replacing the laser interference fringes

California at San Diego, University of

202

Spatial and temporal heterogeneity in supercooled glycerol: Evidence from wide field single molecule imaging  

E-print Network

Spatial and temporal heterogeneity in supercooled glycerol: Evidence from wide field single; published online 30 December 2009 We quantify spatial and temporal heterogeneity in supercooled glycerol times of the molecules identified as heterogeneous relative to glycerol's structural relaxation time

Kaufman, Laura

203

A Wide-Field Survey of the Globular Cluster Systems of Giant Galaxies  

E-print Network

I present selected results from a wide-field CCD survey of the globular cluster systems of giant galaxies, including showing how measurements of the specific frequency of metal-poor globular clusters can constrain the redshift of their formation.

Katherine L. Rhode

2006-05-12

204

Th`ese d'Habilitation Photometric Calibration of Wide Field  

E-print Network

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 2 Stellar Calibration 37 2.1 Flux CalibrationTh`ese d'Habilitation Photometric Calibration of Wide Field Imagers On Light Emitting Diodes, Stars Instrumental Calibration 71 3.1 Metrology chain

Boyer, Edmond

205

The Future of Fiber-Optic Computer Networks  

Microsoft Academic Search

The author discusses research activities in the area of third-generation (all-optical) fiber-optic networks and where they are heading. Applications, the era of single unrepeated links, the characteristics of fiber paths in networks, forms of addressing, overall network throughput capacity, technologies, protocol layers, and making the communication layers invisible are discussed

Paul E. Green

1991-01-01

206

Outer density profiles of 19 Galactic globular clusters from deep and wide-field imaging  

Microsoft Academic Search

Using deep photometric data from Wide Field Camera at the Isaac Newton Telescope and Wide Field Imager at the ESO 2.2-m telescope we measure the outer number density profiles of 19 stellar clusters located in the inner region of the Milky Way halo (within a Galactocentric distance range of 10-30 kpc) in order to assess the impact of internal and

Julio A. Carballo-Bello; Mark Gieles; Antonio Sollima; Sergey Koposov; David Martínez-Delgado; Jorge Peñarrubia

2012-01-01

207

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

208

X-Ray Optics: Past, Present, and Future  

NASA Technical Reports Server (NTRS)

X-ray astronomy started with a small collimated proportional counter atop a rocket in the early 1960s. It was immediately recognized that focusing X-ray optics would drastically improve both source location accuracy and source detection sensitivity. In the past 5 decades, X-ray astronomy has made significant strides in achieving better angular resolution, large photon collection area, and better spectral and timing resolutions, culminating in the three currently operating X-ray observatories: Chandra, XMM/Newton, and Suzaku. In this talk I will give a brief history of X-ray optics, concentrating on the characteristics of the optics of these three observatories. Then I will discuss current X-ray mirror technologies being developed in several institutions. I will end with a discussion of the optics for the International X-ray Observatory that I have been developing at Goddard Space Flight Center.

Zhang, William W.

2010-01-01

209

Laser guide star adaptive optics: Present and future  

SciTech Connect

Feasibility demonstrations using one to two meter telescopes have confirmed the utility of laser beacons as wavefront references for adaptive optics systems. Laser beacon architectures suitable for the new generation of eight and ten meter telescopes are presently under study. This paper reviews the concept of laser guide star adaptive optics and the progress that has been made by groups around the world implementing such systems. A description of the laser guide star program at LLNL and some experimental results is also presented.

Olivier, S.S.; Max, C.E.

1993-03-01

210

The origin, history and future of fiber-optic interferometric acoustic sensors for US Navy applications  

Microsoft Academic Search

Fiber-optic interferometric acoustic sensors were first proposed for US Navy applications 36 years ago. This paper will review the origin, development and deployment of these sensors. Future applications will also be discussed.

James H. Cole; Joseph A. Bucaro; Clay K. Kirkendall; Anthony Dandridge

2011-01-01

211

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

212

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

NASA Astrophysics Data System (ADS)

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 of 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 resolution of 6-9 Å and, using a cross-correlation technique, we measured redshifts with a mean accuracy of ~45 km s-1. Results: We present redshift measurements for 6137 galaxies and their first analyses. Details of the spectroscopic observations are reported. The WINGS-SPE has ~30% overlap with previously published data sets, allowing us both to perform 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 triple 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 ? ?_v^4. Table 4, containing the complete redshift catalog, 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/495/707

Cava, A.; Bettoni, D.; Poggianti, B. M.; Couch, W. J.; Moles, M.; Varela, J.; Biviano, A.; D'Onofrio, M.; Dressler, A.; Fasano, G.; Fritz, J.; Kjærgaard, P.; Ramella, M.; Valentinuzzi, T.

2009-03-01

213

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

214

Discovery of two new Galactic candidate luminous blue variables with Wide-field Infrared Survey Explorer  

NASA Astrophysics Data System (ADS)

We report the discovery of two new Galactic candidate luminous blue variable (LBV) stars via detection of circular shells (typical of confirmed and candidate LBVs) and follow-up spectroscopy of their central stars. The shells were detected at 22 ?m in the archival data of the Mid-Infrared All Sky Survey carried out with the Wide-field Infrared Survey Explorer (WISE). Follow-up optical spectroscopy of the central stars of the shells conducted with the renewed Southern African Large Telescope (SALT) showed that their spectra are very similar to those of the well-known LBVs P Cygni and AG Car, and the recently discovered candidate LBV MN112, which implies the LBV classification for these stars as well. The LBV classification of both stars is supported by detection of their significant photometric variability: one of them brightened in the R and I bands by 0.68 ± 0.10 and 0.61 ± 0.04 mag, respectively, during the last 13-18 years, while the second one (known as Hen 3-1383) varies its B, V, R, I and Ks brightnesses by ?0.5-0.9 mag on time-scales from 10 d to decades. We also found significant changes in the spectrum of Hen 3-1383 on a time-scale of ?3 months, which provides additional support for the LBV classification of this star. Further spectrophotometric monitoring of both stars is required to firmly prove their LBV status. We discuss a connection between the location of massive stars in the field and their fast rotation, and suggest that the LBV activity of the newly discovered candidate LBVs might be directly related to their possible runaway status. a USNO B-1 (Monet et al. 2003); bDENIS; c2MASS; dSALT; ePROMPT.

Gvaramadze, V. V.; Kniazev, A. Y.; Miroshnichenko, A. S.; Berdnikov, L. N.; Langer, N.; Stringfellow, G. S.; Todt, H.; Hamann, W.-R.; Grebel, E. K.; Buckley, D.; Crause, L.; Crawford, S.; Gulbis, A.; Hettlage, C.; Hooper, E.; Husser, T.-O.; Kotze, P.; Loaring, N.; Nordsieck, K. H.; O'Donoghue, D.; Pickering, T.; Potter, S.; Romero Colmenero, E.; Vaisanen, P.; Williams, T.; Wolf, M.; Reichart, D. E.; Ivarsen, K. M.; Haislip, J. B.; Nysewander, M. C.; LaCluyze, A. P.

2012-04-01

215

Wide-field photometry of the Galactic globular cluster M22  

NASA Astrophysics Data System (ADS)

We present wide-field photometry of the Galactic globular cluster M22 in the B, V and I passbands for more than 186 000 stars. The study is complemented by the photometry in two narrow-band filters centred on H? and the adjacent continuum, and by infrared J, H and K magnitudes derived from the Two-Micron All-Sky Survey for ~2000 stars. Profiting from this huge data base, we completely characterized the evolved stellar sequences of the cluster by determining a variety of photometric parameters, including new photometric estimates of the mean metallicity, reddening and distance to the cluster. In particular, from our multiwavelength analysis, we re-examined the long-standing metallicity spread problem in M22. According to our data set, we conclude that most of the observed width of the red giant branch must be due to differential reddening, which amounts to a maximum of ?E(B-V) ~= 0.06, although the presence of a small metallicity spread cannot be completely ruled out. More specifically, the maximum metallicity spread allowed by our data is of the order of ?[Fe/H]~= 0.1-0.2 dex, i.e. not much more than that allowed by the photometric errors. Finally, we identified most of the known variable stars and peculiar objects in our field of view. In particular, we have found additional evidence supporting previous optical identifications of the central star of the planetary nebula IRAS 18333-2357, which is associated with M22.

Monaco, L.; Pancino, E.; Ferraro, F. R.; Bellazzini, M.

2004-04-01

216

Preliminary Design of The Wide-Field Infrared Survey Explorer (WISE)  

E-print Network

The Wide-field Infrared Survey Explorer (WISE), a NASA MIDEX mission, will survey the entire sky in four bands from 3.3 to 23 microns with a sensitivity 1000 times greater than the IRAS survey. The WISE survey will extend the Two Micron All Sky Survey into the thermal infrared and will provide an important catalog for the James Webb Space Telescope. Using 1024x1024 HgCdTe and Si:As arrays at 3.3, 4.7, 12 and 23 microns, WISE will find the most luminous galaxies in the universe, the closest stars to the Sun, and it will detect most of the main belt asteroids larger than 3 km. The single WISE instrument consists of a 40 cm diamond-turned aluminum afocal telescope, a two-stage solid hydrogen cryostat, a scan mirror mechanism, and reimaging optics giving 5" resolution (full-width-half-maximum). The use of dichroics and beamsplitters allows four color images of a 47'x47' field of view to be taken every 8.8 seconds, synchronized with the orbital motion to provide total sky coverage with overlap between revolutions. WISE will be placed into a Sun-synchronous polar orbit on a Delta 7320-10 launch vehicle. The WISE survey approach is simple and efficient. The three-axis-stabilized spacecraft rotates at a constant rate while the scan mirror freezes the telescope line of sight during each exposure. WISE is currently in its Preliminary Design Phase, with the mission Preliminary Design Review scheduled for July, 2005. WISE is scheduled to launch in mid 2009; the project web site can be found at www.wise.ssl.berkeley.edu.

A. K. Mainzer; P. Eisenhardt; E. L. Wright; F. Liu; W. Irace; I. Heinrichsen; R. Cutri; V. Duval

2005-08-10

217

A distributed optical grid network infrastructure for future easy-to-use innovative network services  

NASA Astrophysics Data System (ADS)

Extending the researches on wavelength switched optical networks (WSON), efficient integration of the novel optical packet switching network and wavelength switching-based optical circuit switching network technologies which offers both best-effort packet delivery and QoS guaranteed lightpath services has been being studied. In addition, researches on the optical-layer transparent data processing, such as all-optical wavelength multicasting, all-optical 3R regeneration, etc, are conducted simultaneously. It is believed that future innovative optical network services (INSes) would be built on these novel future-proof technologies, and foster colorful applications in the new generation networks. Before the wide applications of INS in different fields, there would be a foreseeable strong requirement for INS firstly posed by pioneer grid applications, e.g., e-science, e-government, and e-banking, etc, which would require the high-performance underlying networks. Our research here is motivated to glue the optical networks and grid applications by integrating lightpath, geographically distributed INS systems and grid resources (e.g., computers, storages, instruments, etc.), and finally offering an easy-to-use high performance networked grid computing environment-optical grid network (OGN) to user applications. In this paper, we introduce our research activities of a distributed optical grid network infrastructure (OGNI), and the creation of the future easy-to-use INS based on OGNI. The proposals have been validated through fieldtrial experiments over a developed WSON testbed.

Xu, Sugang; Harai, Hiroaki; Wada, Naoya

2011-11-01

218

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

219

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

220

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

221

Phase-diverse adaptive optics for future telescopes  

Microsoft Academic Search

Phase Diversity (PD) is a wavefront-sensing technology that offers certain advantages in an Adaptive-Optics (AO) system. Historically, PD has not been considered for use in AO applications because computations have been prohibitive. However, algorithmic and computational-hardware advances have recently allowed use of PD in AO applications. PD is an attractive candidate for AO applications for a variety of reasons. The

Richard G. Paxman; Brian J. Thelen; Ryan J. Murphy; Kurt W. Gleichman; James A. Georges III

2007-01-01

222

Wide field super-resolution surface imaging through plasmonic structured illumination microscopy.  

PubMed

We experimentally demonstrate a wide field surface plasmon (SP) assisted super-resolution imaging technique, plasmonic structured illumination microscopy (PSIM), by combining tunable SP interference (SPI) with structured illumination microscopy (SIM). By replacing the laser interference fringes in conventional SIM with SPI patterns, PSIM exhibits greatly enhanced resolving power thanks to the unique properties of SP waves. This PSIM technique is a wide field, surface super-resolution imaging technique with potential applications in the field of high-speed biomedical imaging. PMID:25014211

Wei, Feifei; Lu, Dylan; Shen, Hao; Wan, Weiwei; Ponsetto, Joseph Louis; Huang, Eric; Liu, Zhaowei

2014-08-13

223

High Resolution Observations using Adaptive Optics: Achievements and Future Needs  

E-print Network

Over the last few years, several interesting observations were obtained with the help of solar Adaptive Optics (AO). In this paper, few observations made using the solar AO are enlightened and briefly discussed. A list of disadvantages with the current AO system are presented. With telescopes larger than 1.5m are expected during the next decade, there is a need to develop the existing AO technologies for large aperture telescopes. Some aspects of this development are highlighted. Finally, the recent AO developments in India are also presented.

K. Sankarasubramanian; T. Rimmele

2008-01-21

224

Phase-diverse adaptive optics for future telescopes  

NASA Astrophysics Data System (ADS)

Phase Diversity (PD) is a wavefront-sensing technology that offers certain advantages in an Adaptive-Optics (AO) system. Historically, PD has not been considered for use in AO applications because computations have been prohibitive. However, algorithmic and computational-hardware advances have recently allowed use of PD in AO applications. PD is an attractive candidate for AO applications for a variety of reasons. The optical hardware required is simple to implement and eliminates non-common path errors. In addition, PD has also been shown to work well with extended scenes that are encountered, for example, when imaging low-contrast solar granulation. PD can estimate high-order continuous aberrations as well as wavefront discontinuities characteristic of segmented-aperture or sparse-aperture telescope designs. Furthermore, the fundamental information content in a PD data set is shown to be greater than that of the correlation Shack-Hartmann wavefront sensor for the limiting case of unresolved objects. These advantages coupled with recent laboratory results (extended-scene closed-loop AO with PD sampling at 100 Hz) highlight the maturation of not only the PD concept and algorithm but the technology as an emerging and viable wavefront sensor for use in AO applications.

Paxman, Richard G.; Thelen, Brian J.; Murphy, Ryan J.; Gleichman, Kurt W.; Georges, James A., III

2007-09-01

225

Nanosecond time-scale switching of permalloy thin film elements studied by wide-field time-resolved Kerr microscopy  

NASA Astrophysics Data System (ADS)

The switching of extended Ni81Fe19 thin film elements with a thickness of 50nm and various shapes (squared, rectangular, pointed) has been studied by time-resolved stroboscopic Kerr microscopy based on a conventional wide-field optical polarization microscope. The elements are deposited on coplanar strip-lines that generate field pulses driven by electronic pulse generators. Time resolution is obtained by imaging with a gated and intensified charge-coupled device camera. The opening can be varied from 250ps to continuous exposure, allowing the comparison of fast magnetization processes and quasistatic switching in slowly varying fields. The latter is typically characterized by the formation of a concertina domain pattern that irreversibly decays in a multidomain ground state by the abrupt motion of vortices and domain walls. After excitation with fast field pulses similar blocked patterns are formed. They dissolve by spatially inhomogeneous rotational processes involving cross-tie-wall-like domain boundaries.

Chumakov, Dmitry; McCord, Jeffrey; Schäfer, Rudolf; Schultz, Ludwig; Vinzelberg, Hartmut; Kaltofen, Rainer; Mönch, Ingolf

2005-01-01

226

Mathematical Design Optimization of Wide-Field X-ray Telescopes: Mirror Nodal Positions and Detector Tilts  

NASA Technical Reports Server (NTRS)

We describe a mathematical formalism for determining the mirror shell nodal positions and detector tilts that optimize the spatial resolution averaged over a field-of-view for a nested x-ray telescope, assuming known mirror segment surface prescriptions and known detector focal surface. The results are expressed in terms of ensemble averages over variable combinations of the ray positions and wavevectors in the flat focal plane intersecting the optical axis at the nominal on-axis focus, which can be determined by Monte-Carlo ray traces of the individual mirror shells. This work is part of our continuing efforts to provide analytical tools to aid in the design process for wide-field survey x-ray astronomy missions.

Elsner, Ronald; O'Dell, Stephen; Ramsey, Brian; Weisskopf, Martin

2011-01-01

227

PyWiFeS: a rapid data reduction pipeline for the Wide Field Spectrograph (WiFeS)  

NASA Astrophysics Data System (ADS)

We present PyWiFeS, a new Python-based data reduction pipeline for the Wide Field Spectrograph (WiFeS). PyWiFeS consists of a series of core data processing routines built on standard scientific Python packages commonly used in astronomical applications. Included in PyWiFeS is an implementation of a new global optical model of the spectrograph which provides wavelengths solutions accurate to ˜0.05 Å (RMS) across the entire detector. The core PyWiFeS package is designed to be scriptable to enable batch processing of large quantities of data, and we present a default format for handling of observation metadata and scripting of data reduction.

Childress, Michael J.; Vogt, Frédéric P. A.; Nielsen, Jon; Sharp, Robert G.

2014-02-01

228

KOALA: a wide-field 1000 element integral-field unit for the Anglo-Australian Telescope  

NASA Astrophysics Data System (ADS)

KOALA, the Kilofibre Optimised Astronomical Lenslet Array, is a wide-field, high efficiency integral field unit being designed for use with the bench mounted AAOmega spectrograph on the AAT. KOALA will have 1000 fibres in a rectangular array with a selectable field of view of either 1390 or 430 sq. arcseconds with a spatial sampling of 1.25" or 0.7" respectively. To achieve this KOALA will use a telecentric double lenslet array with interchangeable fore-optics. The IFU will feed AAOmega via a 31m fibre run. The efficiency of KOALA is expected to be ? 52% at 3700A and ? 66% at 6563°Å with a throughput of > 52% over the entire wavelength range.

Ellis, S. C.; Ireland, M.; Lawrence, J. S.; Tims, J.; Staszak, N.; Brzeski, J.; Parker, Q. A.; Sharp, R.; Bland-Hawthorn, J.; Case, S.; Colless, M.; Croom, S.; Couch, W.; De Marco, O.; Glazebrook, K.; Saunders, W.; Webster, R.; Zucker, D. B.

2012-09-01

229

Mathematical Design Optimization of Wide-Field X-ray Telescopes: Mirror Nodal Positions and Detector Tilts  

NASA Technical Reports Server (NTRS)

We describe a mathematical formalism for determining the mirror shell nodal positions and detector tilts that optimize the spatial resolution averaged over a field-of-view for a nested x-ray telescope, assuming known mirror segment surface prescriptions and known detector focal surface. The results are expressed in terms of ensemble averages over variable combinations of the ray positions and wave vectors in the flat focal plane intersecting the optical axis at the nominal on-axis focus, which can be determined by Monte-Carlo ray traces of the individual mirror shells. This work is part of our continuing efforts to provide analytical tools to aid in the design process for wide-field survey x-ray astronomy missions.

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

2011-01-01

230

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

231

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

232

Localized plasmon assisted structured illumination microscopy for wide-field high-speed dispersion-  

E-print Network

Localized plasmon assisted structured illumination microscopy for wide-field high-speed dispersion imaging method, i.e. Localized Plasmon assisted Structured Illumination Microscopy (LPSIM), is proposed microscopy (SIM),13­17 plasmonic structured illumination microscopy (PSIM),18 and others.19,20 Although

Wang, Deli

233

Wide-field fluorescence sectioning with hybrid speckle and uniform-illumination microscopy  

E-print Network

or structured illumination microscopies (see [2] and references therein). More recently, a strategyWide-field fluorescence sectioning with hybrid speckle and uniform-illumination microscopy Daryl. A possible strat- egy to speed up DSI microscopy is to use only a single speckle-illumination image

234

Continuous-wave self-pumped phase conjugator with wide field of view  

Microsoft Academic Search

A self-pumped phase conjugator is demonstrated that operates over a wide field of view, phase conjugates separate images without cross talk, and when pumped by one incident beam will self-oscillate with mirrors placed in all four quadrants. The phase conjugator uses a single crystal of BaTiO3.

Jack Feinberg

1983-01-01

235

Discrimination of wide-field images as a test of a peripheral-vision model  

E-print Network

Discrimination of wide-field images as a test of a peripheral-vision model Eli Peli Schepens Eye of images and scenes in a variety of experimental contexts.1­7 One such multiscale model of spatial vision vision model to versions of the same images that differed in con- trast. In the present study we used

Peli, Eli

236

Application of the wide-field shadowgraph technique to rotor wake visualization  

NASA Technical Reports Server (NTRS)

The wide field shadowgraph technique is reviewed along with its application to the visualization of rotor wakes. In particular, current experimental methods and data reduction requirements are discussed. Sample shadowgraphs are presented. These include shadowgraphs of model-scale helicopter main rotors and tilt rotors, and full scale tail rotors, both in hover and in forward flight.

Norman, Thomas R.; Light, Jeffrey S.

1989-01-01

237

114Exploring Power-Law Functions Using WISE Data! The Wide-field Infrared Survey Experiment  

E-print Network

, galaxies, asteroids and other objects that shine brightly in the infrared spectrum. The image to the left114Exploring Power-Law Functions Using WISE Data! The Wide-field Infrared Survey Experiment (WISE 'First Light' image near the bright star V482 Carinae seen to the right. Astronomers not only study

238

Focal plane instrumentation for the Wide-Field X-ray Telescope  

E-print Network

The three X-ray imaging focal planes of the Wide-Field X-ray Telescope (WFXT) Mission will each have a field of view up to 1 degree square, pixel pitch smaller than 1 arcsec, excellent X-ray detection efficiency and spectral ...

Bautz, Marshall W.

239

A Wide-Field Survey of the Globular Cluster Systems of Elliptical and Spiral Galaxies  

Microsoft Academic Search

We have undertaken a survey of the globular cluster (GC) systems of a large sample of elliptical and spiral galaxies, with the aim of using their observed properties to test models of galaxy formation. The survey combines wide-field, ground-based CCD imaging with archival Hubble Space Telescope data to determine the total numbers, spatial distributions and color distributions of GCs around

Katherine Louise Rhode

2003-01-01

240

Improved Infrared Focal Plane Arrays for HST\\/Wide Field Camera 3  

Microsoft Academic Search

Wide Field Camera 3 is a powerful UV\\/visible\\/near-IR imager currently in development for installation into the Hubble Space Telescope. The IR channel of the instrument covers the wavelength range from 800 to 1700nm and will provide HST with a powerful capability for studying high-redshift galaxies, high-redshift Type Ia supernova \\

R. A. Kimble; J. W. MacKenty; R. J. Hill; M. Robberto; G. Delo; R. Foltz; E. M. Malumuth; S. Reed; A. M. Russell; A. Waczynski; Y. Wen; D. Figer

2005-01-01

241

Star-Cluster Astrometry with Ground-Based Wide Field Imagers  

E-print Network

We show the astrometric potential of the Wide Field Imager at the focus of the MPI-ESO 2.2m Telescope. Currently, we are able to measure the position of a well-exposed star with a precision of $\\sim$4 mas/frame in each coordinate (under 0.8 arcsec seeing conditions). We present some preliminary results here.

L. R. Bedin; J. Anderson; G. Piotto; Y. Momany; R. S. Yadav

2005-03-30

242

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.

243

The Observer, October 2003 page 3 Wide-Field Imaging at Fresno State's Campus Observatory  

E-print Network

) and M8, the Lagoon Nebula (right), black-and-white negative, made with the ST-8 camera through the 70-mm it for beginning astro-imagers, and for wide-field imaging in general. Figure 1: M20, the Trifid Nebula (left

Ringwald, Frederick A.

244

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

245

Development of Wide-Field Imaging Camera for Zodiacal Light Observation  

Microsoft Academic Search

We have developed a wide-field imaging camera system, called WICZO, to monitor light of the night sky over extended period. Such monitoring is necessary for studying the morphology of interplanetary dust cloud and also the time and spatial variations of airglow emission. The system consists of an electric cooler, a CCD camera with ~60% quantum efficiency at 500nm, and a

S. M. Kwon; S. S. Hong; K. J. Shin

2004-01-01

246

Flight performance of an advanced CZT imaging detector in a balloon-borne wide-field hard X-ray telescope—ProtoEXIST1  

NASA Astrophysics Data System (ADS)

We successfully carried out the first high-altitude balloon flight of a wide-field hard X-ray coded-aperture telescope ProtoEXIST1, which was launched from the Columbia Scientific Balloon Facility at Ft. Sumner, New Mexico on October 9, 2009. ProtoEXIST1 is the first implementation of an advanced CdZnTe (CZT) imaging detector in our ongoing program to establish the technology required for next generation wide-field hard X-ray telescopes such as the High Energy Telescope (HET) in the Energetic X-ray Imaging Survey Telescope (EXIST). The CZT detector plane in ProtoEXIST1 consists of an 8×8 array of closely tiled 2 cm×2 cm×0.5 cm thick pixellated CZT crystals, each with 8×8 pixels, mounted on a set of readout electronics boards and covering a 256 cm2 active area with 2.5 mm pixels. A tungsten mask, mounted at 90 cm above the detector provides shadowgrams of X-ray sources in the 30-600 keV band for imaging, allowing a fully coded field of view of 9°×9° (and 19°×19° for 50% coding fraction) with an angular resolution of 20?. In order to reduce the background radiation, the detector is surrounded by semi-graded (Pb/Sn/Cu) passive shields on the four sides all the way to the mask. On the back side, a 26 cm×26 cm×2 cm CsI(Na) active shield provides signals to tag charged particle induced events as well as ?100keV background photons from below. The flight duration was only about 7.5 h due to strong winds (60 knots) at float altitude (38-39 km). Throughout the flight, the CZT detector performed excellently. The telescope observed Cyg X-1, a bright black hole binary system, for ˜1h at the end of the flight. Despite a few problems with the pointing and aspect systems that caused the telescope to track about 6.4° off the target, the analysis of the Cyg X-1 data revealed an X-ray source at 7.2? in the 30-100 keV energy band at the expected location from the optical images taken by the onboard daytime star camera. The success of this first flight is very encouraging for the future development of the advanced CZT imaging detectors (ProtoEXIST2, with 0.6 mm pixels), which will take advantage of the modularization architecture employed in ProtoEXIST1.

Hong, J.; Allen, B.; Grindlay, J.; Barthelemy, S.; Baker, R.; Garson, A.; Krawczynski, H.; Apple, J.; Cleveland, W. H.

2011-10-01

247

UVUDF: Ultraviolet Imaging of the Hubble Ultra Deep Field with Wide-Field Camera 3  

NASA Astrophysics Data System (ADS)

We present an overview of a 90 orbit Hubble Space Telescope treasury program to obtain near-ultraviolet imaging of the Hubble Ultra Deep Field using the Wide Field Camera 3 UVIS detector with the F225W, F275W, and F336W filters. This survey is designed to: (1) investigate the episode of peak star formation activity in galaxies at 1 < z < 2.5; (2) probe the evolution of massive galaxies by resolving sub-galactic units (clumps); (3) examine the escape fraction of ionizing radiation from galaxies at z ~ 2-3; (4) greatly improve the reliability of photometric redshift estimates; and (5) measure the star formation rate efficiency of neutral atomic-dominated hydrogen gas at z ~ 1-3. In this overview paper, we describe the survey details and data reduction challenges, including both the necessity of specialized calibrations and the effects of charge transfer inefficiency. We provide a stark demonstration of the effects of charge transfer inefficiency on resultant data products, which when uncorrected, result in uncertain photometry, elongation of morphology in the readout direction, and loss of faint sources far from the readout. We agree with the STScI recommendation that future UVIS observations that require very sensitive measurements use the instrument's capability to add background light through a "post-flash." Preliminary results on number counts of UV-selected galaxies and morphology of galaxies at z ~ 1 are presented. We find that the number density of UV dropouts at redshifts 1.7, 2.1, and 2.7 is largely consistent with the number predicted by published luminosity functions. We also confirm that the image mosaics have sufficient sensitivity and resolution to support the analysis of the evolution of star-forming clumps, reaching 28-29th magnitude depth at 5? in a 0.''2 radius aperture depending on filter and observing epoch. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are #12534.

Teplitz, Harry I.; Rafelski, Marc; Kurczynski, Peter; Bond, Nicholas A.; Grogin, Norman; Koekemoer, Anton M.; Atek, Hakim; Brown, Thomas M.; Coe, Dan; Colbert, James W.; Ferguson, Henry C.; Finkelstein, Steven L.; Gardner, Jonathan P.; Gawiser, Eric; Giavalisco, Mauro; Gronwall, Caryl; Hanish, Daniel J.; Lee, Kyoung-Soo; de Mello, Duilia F.; Ravindranath, Swara; Ryan, Russell E.; Siana, Brian D.; Scarlata, Claudia; Soto, Emmaris; Voyer, Elysse N.; Wolfe, Arthur M.

2013-12-01

248

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

249

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

E-print Network

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 cancelation, 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 cancelation schemes. We show that it is feasible to demonstrate such an effect with the {\\it Gingin High Optical Power Test Facility}, and it can eventually be implemented in future advanced GW detectors.

Farid Khalili; Stefan Danilishin; Helge Mueller-Ebhardt; Haixing Miao; Yanbei Chen; Chunnong Zhao

2010-10-06

250

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

NASA Astrophysics Data System (ADS)

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; Müller-Ebhardt, Helge; Miao, Haixing; Chen, Yanbei; Zhao, Chunnong

2011-03-01

251

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

252

Effects of spatial and spectral frequencies on wide-field functional imaging (wifi) characterization of preclinical breast cancer models  

NASA Astrophysics Data System (ADS)

A common strategy to study breast cancer is the use of the preclinical model. These models provide a physiologically relevant and controlled environment in which to study both response to novel treatments and the biology of the cancer. Preclinical models, including the spontaneous tumor model and mammary window chamber model, are very amenable to optical imaging and to this end, we have developed a wide-field functional imaging (WiFI) instrument that is perfectly suited to studying tumor metabolism in preclinical models. WiFI combines two optical imaging modalities, spatial frequency domain imaging (SFDI) and laser speckle imaging (LSI). Our current WiFI imaging protocol consists of multispectral imaging in the near infrared (650-980 nm) spectrum, over a wide (7 cm x 5 cm) field of view. Using SFDI, the spatially-resolved reflectance of sinusoidal patterns projected onto the tissue is assessed, and optical properties of the tissue are determined, which are then used to extract tissue chromophore concentrations in the form of oxy-, deoxy-, and total hemoglobin concentrations, and percentage of lipid and water. In the current study, we employ Monte Carlo simulations of SFDI light propagation in order to characterize the penetration depth of light in both the spontaneous tumor model and mammary window chamber model. Preliminary results suggest that different spatial frequency and wavelength combinations have different penetration depths, suggesting the potential depth sectioning capability of the SFDI component of WiFI.

Moy, Austin; Kim, Jae G.; Lee, Eva Y. H. P.; Choi, Bernard

2010-02-01

253

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

254

Segmented X-ray optics for future space telescopes  

NASA Astrophysics Data System (ADS)

Lightweight and high resolution mirrors are needed for future space-based X-ray telescopes to achieve advances in high-energy astrophysics. The slumped glass mirror technology in development at NASA GSFC aims to build X-ray mirror modules with an area to mass ratio of ~17 cm2/kg at 1 keV and a resolution of 10 arc-sec Half Power Diameter (HPD) or better at an affordable cost. As the technology nears the performance requirements, additional engineering effort is needed to ensure the modules are compatible with space-flight. This paper describes Flight Mirror Assembly (FMA) designs for several X-ray astrophysics missions studied by NASA and defines generic driving requirements and subsequent verification tests necessary to advance technology readiness for mission implementation. The requirement to perform X-ray testing in a horizontal beam, based on the orientation of existing facilities, is particularly burdensome on the mirror technology, necessitating mechanical over-constraint of the mirror segments and stiffening of the modules in order to prevent self-weight deformation errors from dominating the measured performance. This requirement, in turn, drives the mass and complexity of the system while limiting the testable angular resolution. Design options for a vertical X-ray test facility alleviating these issues are explored. An alternate mirror and module design using kinematic constraint of the mirror segments, enabled by a vertical test facility, is proposed. The kinematic mounting concept has significant advantages including potential for higher angular resolution, simplified mirror integration, and relaxed thermal requirements. However, it presents new challenges including low vibration modes and imperfections in kinematic constraint. Implementation concepts overcoming these challenges are described along with preliminary test and analysis results demonstrating the feasibility of kinematically mounting slumped glass mirror segments.

McClelland, R. S.

255

A Nulling Wide Field Imager for Exoplanets Detection and General Astrophysics  

E-print Network

We present a solution to obtain a high-resolution image of a wide field with the central source removed by destructive interference. The wide-field image is created by aperture synthesis with a rotating sparse array of telescopes in space. Nulling of the central source is achieved using a phase-mask coronagraph. The full (u,v) plane coverage delivered by the 60m, six 3-meter telescope array is particularly well-suited for the detection and characterization of exoplanets in the infrared (DARWIN and Terrestrial Planet Finder (TPF) missions) as well as for other generic science observations. Detection (S/N=10) of an Earth-like planet is achieved in less than 10 hours with a 1 micron bandwidth at 10 micron.

Olivier Guyon; Francois Roddier

2002-05-30

256

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

257

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

Microsoft Academic Search

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

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

1994-01-01

258

Cosmic Rays In Multi-Orbit Images With The HST Wide Field Planetary Camera 2  

Microsoft Academic Search

In the July 1994 PASP (Vol. 106, p. 798), we presented an optimized algorithm that removes cosmic rays (CR's) from multi-orbit HST Wide Field\\/Planetary Camera (WF\\/PC-1) images. The algorithm was shown to work best at clipping levels of =~ 2.0-2.5times sigma_ {Poisson} when 4--6 unshifted exposures are available, while for 6--12 exposures the optimal clipping level is =~ 1.8-2.0sigma_ {Poisson}.

Barbara E. Franklin; Rogier A. Windhorst

1994-01-01

259

The Kepler Mission: A wide-field transit search for terrestrial planets  

Microsoft Academic Search

The Kepler Mission is a NASA Discovery mission which will continuously monitor the brightness of at least 100,000 main sequence stars, to detect the transits of terrestrial and larger planets. It is scheduled to be launched in 2007 into an Earth-trailing heliocentric orbit. It is a wide-field photometer with a Schmidt-type telescope and array of 42 CCDs covering the 100

Gibor Basri; William J. Borucki; David Koch

2005-01-01

260

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

Microsoft Academic Search

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

Carl Maag; Jerry Millard; Mark Anderson

1990-01-01

261

The wide field imager for the 2.2-m MPG\\/ESO telescope: a preview  

Microsoft Academic Search

In November 1995, the La Silla 2000 working group of the Scientific Technical Committee (STC) as well as the Observing Programmes Committee (OPC) identified a very strong demand by the ESO community for wide-field imaging (0.5-2 degrees) capabilities (cf. Andersen, J. 1996: The Messenger, No. 83, p. 48). In all major areas of research, the primary driver was the identification

D. Baade; K. Meisenheimer; O. Iwert; J. Alonso; P. Amico; T. Augusteijn; J. Beletic; H. Bellemann; W. Benesch; H. Böhm; H. Böhnhardt; S. Deiries; B. Delabre; R. Donaldson; C. Dupuy; O. Franke; R. Gerdes; R. Gilmozzi; B. Grimm; N. Haddad; G. Hess; H. Klein; R. Lenzen; J.-L. Lizon; D. Mancini; N. Münch; G. Rahmer; J. Reyes; E. Robledo; A. Silber

1998-01-01

262

The Wide Field Cameras onboard the BeppoSAX X-ray Astronomy Satellite  

Microsoft Academic Search

The two Wide Field Cameras (WFCs) currently flying on the Italian\\/Dutch X-ray satellite BeppoSAX, image the X-ray sky in the energy range of 1.8 - 28 keV. The field of view is 20 degrees, the angular resolution is 5 arcmin and the energy resolution is 20% at 6 keV, while the source location accuracy will generally be better than one

R. Jager; W. A. Mels; A. C. Brinkman; M. Y. Galama; H. Goulooze; J. Heise; P. Lowes; J. M. Muller; A. Naber; A. Rook; R. Schuurhof; J. J. Schuurmans; G. Wiersma

1997-01-01

263

A new family of non--linear filters for background subtraction of wide--field surveys  

E-print Network

In this paper the definitions and the properties of a newle dedicated set of high-frequency filters based on smoothing-and-clipping are briefly described. New applications for reduction of wide--field 2048x2048 CCD spectral and direct images of a new deep survey KISS (KPNO International Spectral Survey) are also presented. The developed software is available both as a C subroutine and as an installed MIDAS environment command.

V. S. Shergin; A. Yu. Kniazev; V. A. Lipovetsky

1996-06-14

264

The AGN Content of the NOAO Deep Wide Field Survey at Milliarcsecond Resolution  

Microsoft Academic Search

We are using the NRAO Very Long Baseline Array (VLBA) at 5 GHz to observe compact FIRST sources stronger than 10 mJy in the NOAO Deep Wide-Field Survey (NDWFS). Our study of 206 sources at milliarcsecond resolution overcomes two limitations of past VLBI surveys for active galactic nuclei (AGN), namely biases introduced by targeting flat-spectrum sources stronger than 200 mJy,

T. A. Rector; J. M. Wrobel; G. B. Taylor; S. T. Myers; C. D. Fassnacht

2004-01-01

265

The AGN Content of the NOAO Deep Wide Field Survey at Milliarcsecond Resolution  

Microsoft Academic Search

We are using the NRAO Very Long Baseline Array (VLBA) at 5 GHz to observe compact FIRST sources stronger than 10 mJy in the NOAO Deep Wide-Field Survey (NDWFS). Our study of 206 sources at milliarcsecond resolution overcomes two limitations of past VLBI surveys for active galactic nuclei (AGN), namely biases introduced by targeting flat-spectrum sources stronger than 200 mJy,

T. A. Rector; J. M. Wrobel; G. B. Taylor; S. T. Myers; C. D. Fassnacht

2002-01-01

266

On the design of wide-field x-ray telescopes  

Microsoft Academic Search

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

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

2009-01-01

267

Hubble Space Telescope Wide Field Planetary Camera 2 Observations of HH 1-2  

Microsoft Academic Search

We present Hubble Space Telescope Wide Field Planetary Camera 2 images of the bipolar Herbig-Haro complex HH 1-2 in three emission lines (Halpha, [S ii], and [O iii]) and one continuum band (F702W). In addition to showing the complex morphology of these objects, the WFPC2 data allow us to resolve the cooling and recombination regions behind radiative shocks. This provides

J. Jeff Hester; Karl R. Stapelfeldt; Paul A. Scowen

1998-01-01

268

The 64 Mpixel wide field imager for the Wendelstein 2m Telescope: Design and Calibration  

E-print Network

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 (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...

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

2014-01-01

269

Wide-field imaging by leakage of surface plasmon-coupled fluorescence  

NASA Astrophysics Data System (ADS)

In this work we present a new imaging technique that combines advantages of wide-field surface plasmon (WFSP), leakage radiation (LR) and total internal reflection florescence (TIRF) microscopy methods. We demonstrate high-resolution non-scanning (wide-field) imaging of fluorescent samples using a LR configuration. We modified the glass-metal-sample arrangement to be imaged by adding a top thin film with a refractive index equal to or smaller than the glass. The top thin film is fabricated by spinning a diluted fluorescent compound (dye) over the original glass-metal-sample arrangement. Illumination from a low numerical aperture microscopic lens is used to excite incoherent fluorescent radiation in the top thin film. Leakage radiation due to plasmon-coupled fluorescence is collected by an oil-immersion microscope objective lens in direct contact with the glass side of the sample arrangement. The use of incoherent plasmon-coupled fluorescent radiation for sample illumination dispenses the need of a rotating diffuser in the proposed wide-field leakage plasmon-coupled fluorescence (WFLPCF) microscope. This also provides a way to obtain high resolution non-scanning images without the need of a spatial modulator.

Chesnutt, Catherine; Frisbie, Stephen; Grave-de-Peralta, Luis; Bernussi, Ayrton

2009-04-01

270

Wide-field four-channel fluorescence imager for biological applications  

NASA Astrophysics Data System (ADS)

A wide-field four-channel fluorescence imager has been developed. The instrument uses four expanded laser beams to image a large section (6 mm×9 mm). An object can be sequentially illuminated with any combination of 408-, 532-, 658-, and 784-nm lasers for arbitrary (down to 1 ms) exposure times for each laser. Just two notch filters block scattered light from all four lasers. The design approach described here offers great flexibility in treatment of objects, very good sensitivity, and a wide field of view at low cost. There appears to be no commercial instrument capable of simultaneous fluorescence imaging of a wide field of view with four-laser excitation. Some possible applications are following events such as flow and mixing in microchannel systems, the transmission of biological signals across a culture, and following simulations of biological membrane diffusion. It can also be used in DNA sequencing by synthesis to follow the progress of the photolytic removal of dye and terminator. Without utilizing its time resolution, it can be used to obtain four independent images of a single tissue section stained with four targeting agents, with each coupled to a different dye matching one of the lasers.

Thakur, Madhuri; Melnik, Dmitry; Barnett, Heather; Daly, Kevin; Moran, Christine H.; Chang, Wei-Shun; Link, Stephan; Bucher, Christopher Theodore; Kittrell, Carter; Curl, Robert

2010-03-01

271

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

272

Optical Tweezers and Optical Trapping Improved for Future Automated Micromanipulation and Characterization  

NASA Technical Reports Server (NTRS)

Optical trap arrays are being developed at the NASA Glenn Research Center for holding, manipulating, and optically interrogating arrays of nanotube sensors. The trap arrays, for example, might be used to arrange arrays of chemical sensors for insertion onto a chip in liquid, air, and vacuum environments. Neural-network-controlled spatial light modulators (SLMs) are to generate and control the trap positions and trap profiles in three dimensions.

Wrbanek, Susan Y.; Decker, Arthur J.

2005-01-01

273

Optical Packet and Burst Switching Technologies for the Future Photonic Internet  

NASA Astrophysics Data System (ADS)

This paper reviews advanced optical burst switching (OBS) and optical packet switching (OPS) technologies and discusses their roles in the future photonic Internet. Discussions include optoelectronic and optical systems technologies as well as systems integration into viable network elements (OBS and OPS routers). Optical label switching (OLS) offers a unified multiple-service platform with effective and agile utilization of the available optical bandwidth in support of voice, data, and multimedia services on the Internet Protocol. In particular, OLS routers with wavelength routing switching fabrics and parallel optical labeling allow forwarding of asynchronously arriving variable-length packets, bursts, and circuits. By exploiting contention resolution in wavelength, time, and space domains, the OLS routers can achieve high throughput without resorting to a store-and-forward method associated with large buffer requirements. Testbed demonstrations employing OLS edge routers show high-performance networking in support of multimedia and data communications applications over the photonic Internet with optical packets and bursts switched directly at the optical layer.

Ben Yoo, S. J.

2006-12-01

274

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

275

SIMULTANEOUS EXOPLANET CHARACTERIZATION AND DEEP WIDE-FIELD IMAGING WITH A DIFFRACTIVE PUPIL TELESCOPE  

SciTech Connect

High-precision astrometry can identify exoplanets and measure their orbits and masses while coronagraphic imaging enables detailed characterization of their physical properties and atmospheric compositions through spectroscopy. In a previous paper, we showed that a diffractive pupil telescope (DPT) in space can enable sub-{mu}as accuracy astrometric measurements from wide-field images by creating faint but sharp diffraction spikes around the bright target star. The DPT allows simultaneous astrometric measurement and coronagraphic imaging, and we discuss and quantify in this paper the scientific benefits of this combination for exoplanet science investigations: identification of exoplanets with increased sensitivity and robustness, and ability to measure planetary masses to high accuracy. We show how using both measurements to identify planets and measure their masses offers greater sensitivity and provides more reliable measurements than possible with separate missions, and therefore results in a large gain in mission efficiency. The combined measurements reliably identify potentially habitable planets in multiple systems with a few observations, while astrometry or imaging alone would require many measurements over a long time baseline. In addition, the combined measurement allows direct determination of stellar masses to percent-level accuracy, using planets as test particles. We also show that the DPT maintains the full sensitivity of the telescope for deep wide-field imaging, and is therefore compatible with simultaneous scientific observations unrelated to exoplanets. We conclude that astrometry, coronagraphy, and deep wide-field imaging can be performed simultaneously on a single telescope without significant negative impact on the performance of any of the three techniques.

Guyon, Olivier; Eisner, Josh A.; Angel, Roger; Woolf, Neville J. [Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States)] [Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States); Bendek, Eduardo A.; Milster, Thomas D. [College of Optical Sciences, University of Arizona, Tucson, AZ 85721 (United States)] [College of Optical Sciences, University of Arizona, Tucson, AZ 85721 (United States); Ammons, S. Mark [Lawrence Livermore National Laboratory, Physics Division L-210, 7000 East Avenue, Livermore, CA 94550 (United States)] [Lawrence Livermore National Laboratory, Physics Division L-210, 7000 East Avenue, Livermore, CA 94550 (United States); Shao, Michael; Shaklan, Stuart; Levine, Marie; Nemati, Bijan [Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States)] [Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Martinache, Frantz [National Astronomical Observatory of Japan, Subaru Telescope, Hilo, HI 96720 (United States)] [National Astronomical Observatory of Japan, Subaru Telescope, Hilo, HI 96720 (United States); Pitman, Joe [Exploration Sciences, P.O. Box 24, Pine, CO 80470 (United States)] [Exploration Sciences, P.O. Box 24, Pine, CO 80470 (United States); Woodruff, Robert A. [Lockheed Martin, 2081 Evergreen Avenue, Boulder, CO 80304 (United States)] [Lockheed Martin, 2081 Evergreen Avenue, Boulder, CO 80304 (United States); Belikov, Ruslan, E-mail: guyon@naoj.org [NASA Ames Research Center, Moffett Field, CA 94035 (United States)] [NASA Ames Research Center, Moffett Field, CA 94035 (United States)

2013-04-10

276

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

277

The TERAPIX Tool for the Reduction of Wide-Field Images  

NASA Astrophysics Data System (ADS)

TERAPIX (Traitement Élémentaire Réduction et Analyse des PIXels) is an astronomical data processing center located at IAP (Institut d'Astrophysique de Paris). TERAPIX is aimed to the processing of mosaics of wide-field images from CFH12K and MEGACAM at CFHT, WFI at ESO and OMEGACAM at VST: at present more than 2 Terabytes of disk space are available, as well as three COMPAQ workstations with EV5, EV6 and EV67 processors see http://www.terapix.iap.fr for more details

Radovich, M.; Mellier, Y.; Bertin, E.; Missonnier, G.; Didelon, P.; Morin, B.; Dantel-Fort, M.; McCracken, H.

278

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

279

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

280

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

281

All-Optical Regeneration for Ultra-Long Fiber Links and its Prospects for Future Applications with New Modulation  

E-print Network

All-Optical Regeneration for Ultra-Long Fiber Links and its Prospects for Future Applications of California, Davis, 95616 Email: sbyoo@ucdavis.edu Abstract: We will discuss all-optical regeneration-optical regeneration in ultra-long fiber links can potentially bring significant cost savings due to reduced power

Kolner, Brian H.

282

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

283

WSCLEAN: an implementation of a fast, generic wide-field imager for radio astronomy  

NASA Astrophysics Data System (ADS)

Astronomical wide-field imaging of interferometric radio data is computationally expensive, especially for the large data volumes created by modern non-coplanar many-element arrays. We present a new wide-field interferometric imager that uses the w-stacking algorithm and can make use of the w-snapshot algorithm. The performance dependences of CASA's w-projection and our new imager are analysed and analytical functions are derived that describe the required computing cost for both imagers. On data from the Murchison Widefield Array, we find our new method to be an order of magnitude faster than w-projection, as well as being capable of full-sky imaging at full resolution and with correct polarization correction. We predict the computing costs for several other arrays and estimate that our imager is a factor of 2-12 faster, depending on the array configuration. We estimate the computing cost for imaging the low-frequency Square Kilometre Array observations to be 60 PetaFLOPS with current techniques. We find that combining w-stacking with the w-snapshot algorithm does not significantly improve computing requirements over pure w-stacking. The source code of our new imager is publicly released.

Offringa, A. R.; McKinley, B.; Hurley-Walker, N.; Briggs, F. H.; Wayth, R. B.; Kaplan, D. L.; Bell, M. E.; Feng, L.; Neben, A. R.; Hughes, J. D.; Rhee, J.; Murphy, T.; Bhat, N. D. R.; Bernardi, G.; Bowman, J. D.; Cappallo, R. J.; Corey, B. E.; Deshpande, A. A.; Emrich, D.; Ewall-Wice, A.; Gaensler, B. M.; Goeke, R.; Greenhill, L. J.; Hazelton, B. J.; Hindson, L.; Johnston-Hollitt, M.; Jacobs, D. C.; Kasper, J. C.; Kratzenberg, E.; Lenc, E.; Lonsdale, C. J.; Lynch, M. J.; McWhirter, S. R.; Mitchell, D. A.; Morales, M. F.; Morgan, E.; Kudryavtseva, N.; Oberoi, D.; Ord, S. M.; Pindor, B.; Procopio, P.; Prabu, T.; Riding, J.; Roshi, D. A.; Shankar, N. Udaya; Srivani, K. S.; Subrahmanyan, R.; Tingay, S. J.; Waterson, M.; Webster, R. L.; Whitney, A. R.; Williams, A.; Williams, C. L.

2014-10-01

284

WPOL: a DSSD-based hard x-ray wide field imager and polarimeter  

NASA Astrophysics Data System (ADS)

WPOL (Wide field camera with POLarimetry) is a wide field camera which aims to monitor the X-ray/low gamma-ray sources and measures their polarimetric properties. This camera will be operated in space to trigger a main instrument in case of transient events (gamma-ray bursts, black hole binaries state transition, supernovae, …) and to map the Xray/ gamma-ray polarized sources of the Galaxy, which has never been done up to now. It will be proposed, as an accompanying instrument, in the context of the next medium mission ESA call (M4). The concept of the instrument is based upon a coded mask imaging with a detector unit composed of two planes of Silicon double sided stripped detectors (DSSD), a passive collimator and a tungsten mask. Mapping is done on the first plane through mask imaging and polarization is measured by studying Compton scattering events between the two planes. The source direction in the sky being known through the mask pattern projected on the detector plane, and the scattered photon direction being measured between the two planes, only the determination of the first energy deposit is needed to compute the whole Compton scattering kinetics and in particular, to determine the source photon energy

Laurent, P.; Bertoli, W.; Breelle, E.; Dolgorouky, Y.; Gouiffès, C.; Khalil, M.; Limousin, O.; Lebrun, F.; Rodriguez, J.

2014-07-01

285

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

286

Imaging design of the wide field x-ray monitor onboard the HETE satellite  

NASA Astrophysics Data System (ADS)

The High Energy Transient Experiment (HETE), to be launched in 1995, will study Gamma-Ray Bursts in an unprecendented wide wavelength range from Gamma and X-ray to UV wavelengths. The X-ray range (2 to 25 keV) will be covered by 2 perpendicularly oriented 1-dimensional coded aperture cameras. These instruments cover a wide field of view of 2 sr and thus have a relatively large potential to locate GRB's to a fraction of a degree, which is an order of magnitude better than BATSE. The imaging design of these coded aperture cameras relates to the design of the coded apertures and the decoding algorithm. The aperture pattern is to a large extent determined by the high background in this wide field application and the low number of pattern elements ((approximately)100) in each direction. The result is a random pattern with an open fraction of 33%. The onboard decoding algorithm is dedicated to the localization of a single point source.

Intzand, Jean J. M.; Fenimore, E. E.; Kawai, N.; Yoshida, A.; Matsuoka, M.; Yamauchi, M.

287

The design of the wide field monitor for the LOFT mission  

NASA Astrophysics Data System (ADS)

LOFT (Large Observatory For x-ray Timing) is one of the ESA M3 missions selected within the Cosmic Vision program in 2011 to carry out an assessment phase study and compete for a launch opportunity in 2022-2024. The phase-A studies of all M3 missions were completed at the end of 2013. LOFT is designed to carry on-board two instruments with sensitivity in the 2-50 keV range: a 10 m2 class Large Area Detector (LAD) with a <1° collimated FoV and a wide field monitor (WFM) making use of coded masks and providing an instantaneous coverage of more than 1/3 of the sky. The prime goal of the WFM will be to detect transient sources to be observed by the LAD. However, thanks to its unique combination of a wide field of view (FoV) and energy resolution (better than 500 eV), the WFM will be also an excellent monitoring instrument to study the long term variability of many classes of X-ray sources. The WFM consists of 10 independent and identical coded mask cameras arranged in 5 pairs to provide the desired sky coverage. We provide here an overview of the instrument design, configuration, and capabilities of the LOFT WFM. The compact and modular design of the WFM could easily make the instrument concept adaptable for other missions.

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

2014-07-01

288

Free-space optical communications in support of future manned space flight  

NASA Technical Reports Server (NTRS)

Four areas of research in optical communications in support of future manned space missions being carried out at Johnson Space Center are discussed. These are the Space Station Freedom proximity operations, direct LEO-to-ground communications, IR voice communications inside manned spacecraft, and deep space and lunar satellite operations. The background, requirements, and scenario for each of these areas of research are briefly described.

Stephens, Elaine M.

1990-01-01

289

Cryogenic Optical Performance of a Light-weight Mirror Assembly for Future Space Astronomical Telescopes: Optical Test Results and Thermal Optical Model  

NASA Technical Reports Server (NTRS)

A 40 cm diameter mirror assembly was interferometrically tested at room temperature down to 250 degrees Kelvin for thermal deformation. The 2.5 m radius of curvature spherical mirror assembly was constructed by low temperature fusing three abrasive waterjet core sections between two face sheets. The 93% lightweighted Corning ULE mirror assembly represents the current state of the art for future UV, optical, near IR space telescopes. During the multiple thermal test cycles, test results of interferometric test, thermal IR images of the front face were recorded in order to validate thermal optical model.

Eng, Ron; Arnold, William; Baker, Markus A.; Bevan, Ryan M.; Carpenter, James R.; Effinger, Michael R.; Gaddy, Darrell E.; Goode, Brian K.; Kegley, Jeffrey R.; Hogue, William D.; Siler, Richard D.; Smith, W. Scott; Stahl. H. Philip; Tucker, John M.; Wright, Ernest R.; Kirk, Charles S.; Hanson, Craig; Burdick, Gregory; Maffett, Steven

2013-01-01

290

Cryogenic Optical Performance of a Lightweighted Mirror Assembly for Future Space Astronomical Telescopes: Correlating Optical Test Results and Thermal Optical Model  

NASA Technical Reports Server (NTRS)

A 43cm diameter stacked core mirror demonstrator was interferometrically tested at room temperature down to 250 degrees Kelvin for thermal deformation. The 2.5m radius of curvature spherical mirror assembly was constructed by low temperature fusing three abrasive waterjet core sections between two CNC pocket milled face sheets. The 93% lightweighted Corning ULE® mirror assembly represents the current state of the art for future UV, optical, near IR space telescopes. During the multiple thermal test cycles, test results of interferometric test, thermal IR images of the front face were recorded in order to validate thermal optical model.

Eng, Ron; Arnold, William R.; Baker, Marcus A.; Bevan, Ryan M.; Burdick, Gregory; Effinger, Michael R.; Gaddy, Darrell E.; Goode, Brian K.; Hanson, Craig; Hogue, William D.; Kegley, Jeffrey R.; Kirk, Charlie; Maffett, Steven P.; Matthews, Gary W.; Siler, Richard D.; Smith, W. Scott; Stahl, H. Philip; Tucker, John M.; Wright, Ernest R.

2013-01-01

291

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

PubMed

Nanodiamonds containing high density ensembles of negatively charged nitrogen-vacancy (NV(-)) centers are promising fluorescent biomarkers due to their excellent photostability and biocompatibility. The NV(-) centers in the particles have a fluorescence lifetime of up to 20?ns, which distinctly differs from those (<10?ns) of cell and tissue autofluorescence, making it possible to achieve background-free detection in vivo by time gating. Here, we demonstrate the feasibility of using fluorescent nanodiamonds (FNDs) as optical labels for wide-field time-gated fluorescence imaging and flow cytometric analysis of cancer cells with a nanosecond intensified charge-coupled device (ICCD) as the detector. The combined technique has allowed us to acquire fluorescence images of FND-labeled HeLa cells in whole blood covered with a chicken breast of ~0.1-mm thickness at the single cell level, and to detect individual FND-labeled HeLa cells in blood flowing through a microfluidic device at a frame rate of 23?Hz, as well as to locate and trace FND-labeled lung cancer cells in the blood vessels of a mouse ear. It opens a new window for real-time imaging and tracking of transplanted cells (such as stem cells) in vivo. PMID:24994610

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

2014-01-01

292

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

293

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

294

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

295

The 2MASS Wide-Field T Dwarf Search. IV Unting out T dwarfs with Methane Imaging  

E-print Network

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 2MASS photometry. We show that these filters are effective in discriminating T dwarfs from other types of stars, and demonstrate this with Anglo-Australian Telescope observations using the IRIS2 imager. Methane imaging data and proper motions are presented for ten 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.

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

2005-08-05

296

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

297

The NOAA-9 Earth Radiation Budget Experiment Wide Field-of-View Data Set  

NASA Technical Reports Server (NTRS)

The Earth Radiation Budget Experiment (ERBE) consisted of wide field-of-view (WFOV) radiometers and scanning radiometers for measuring outgoing longwave radiation and solar radiation reflected from the Earth. These instruments were carried by the dedicated Earth Radiation Budget Satellite (ERBS) and by the NOAA-9 and -10 operational spacecraft. The WFOV radiometers provided data from which instantaneous fluxes at the top of the atmosphere (TOA) are computed by use of a numerical filter algorithm. Monthly mean fluxes over a 5-degree equal angle grid are computed from the instantaneous TOA fluxes. The WFOV radiometers aboard the NOAA-9 spacecraft operated from February 1985 through December 1992, at which time a failure of the shortwave radiometer ended the usable data after nearly 8 years. This paper examines the monthly mean products from that data set.

Bush, Kathryn A.; Smith, G. Louis; Young, David F.

1999-01-01

298

Wide-field endoscopic fluorescence imaging for gastrointestinal tumor detection with glucose analogue  

NASA Astrophysics Data System (ADS)

The lack of functional information and targeted imaging in conventional white-light endoscopy leads to a high miss-rate of gastrointestinal tumor. The combination of near-infrared fluorescence imaging and endoscopy presents a promising approach. Here we introduce a new endoscopy method employing a home-made flexible wide-field epi-fluorescence endoscope, that can be inserted through the biopsy channel of a gastrointestinal endoscope, with the glucose analogue 2- DeoxyGlucosone as the near-infrared fluorescent probe. System characterization indicates a good sensitivity and linearity over a large field of view. Its capability of tumor identification and location is demonstrated with in-vivo imaging of xenografted tumor model.

He, Yun; Qu, Yawei; Bai, Jing; Liu, Haifeng

2014-05-01

299

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

E-print Network

We employed the ESO MPI wide-field camera and obtained deep images in the VIc pass-bands in the region of the IC 2944/2948 complex (l ~ 294; b ~ -1), and complemented them with literature and archival data. We used this material to derive the photometric, spectroscopic and kinematic properties of the brightest (V 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 ...

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

2014-01-01

300

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

301

An optimal numerical filter for wide-field-of-view measurements of earth-emitted radiation  

NASA Technical Reports Server (NTRS)

A technique is described in which all data points along an arc of the orbit may be used in an optimal numerical filter for wide-field-of-view measurements of earth emitted radiation. The statistical filter design is derived whereby the filter is required to give a minimum variance estimate of the radiative exitance at discrete points along the ground track of the satellite. An equation for the optimal numerical filter is given by minimizing the estimate error variance equation with respect to the filter weights, resulting in a discrete form of the Wiener-Hopf equation. Finally, variances of the errors in the radiant exitance can be computed along the ground track and in the cross track directions.

Smith, G. L.; House, F. B.

1981-01-01

302

The Maunakea Spectroscopic Explorer: from wide field surveys to the TMT  

NASA Astrophysics Data System (ADS)

The Maunakea Spectroscopic Explorer (MSE) is planned to become the world's only fully dedicated 10m-class spectroscopic facility. It will operate at a range of spectral resolutions, from R~2000 to R>=20000, and obtain simultaneously data for more than 3000 sources over a wide (~1.5sq.deg) field of view. It will fill the gap between wide field imaging surveys and TMT, by being the key follow-up facility for surveys such as LSST and Euclid. It will identify from hundreds of thousands of possible targets those objects that should be fed into TMT. I will discuss the current status of MSE, its defining capabilities, its driving science, and the unique scientific synergies provided by MSE and TMT.

McConnachie, Alan

2014-07-01

303

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

304

Wide field-of-view microscope based on holographic focus grid illumination.  

PubMed

We have developed a new microscopy design that can achieve wide field-of-view (FOV) imaging and yet possesses resolution that is comparable to a conventional microscope. In our design, the sample is illuminated by a holographically projected light-spot grid. We acquire images by translating the sample across the grid and detecting the transmissions. We have built a prototype system with an FOV of 6 mm x 5 mm and acquisition time of 2.5 s. The resolution is fundamentally limited by the spot size--our demonstrated average FWHM spot diameter was 0.74 microm. We demonstrate the prototype by imaging a U.S. Air Force target and a lily anther. This technology is scalable and represents a cost-effective way to implement wide FOV microscopy systems. PMID:20596189

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

2010-07-01

305

Stellar Coronal EUV Emission Observed with the ROSAT Wide Field Camera  

NASA Astrophysics Data System (ADS)

The Wide Field Camera (WFC) on the ROSAT satellite conducted the first all-sky survey in the extreme ultraviolet (EUV) over the six month period beginning on 1990 July 30. Two survey filters were used peaking at 95 and 120 Angstroms . Many of the sources detected are coronal stars. We present detailed results from WFC survey data for a range of coronal stars, including a complete survey of the RS CVn systems in the Strassmeier catalog (40% detection rate), the EUV variability of the flare star EV Lac (including the largest flare seen by the WFC from a coronal source), the EUV rotation-activity relation for a homogeneous sample of single early K dwarfs, and WFC results forming part of the RIASS (ROSAT-IUE-All-Sky-Survey) campaign. This work is supported by NASA grant NAG 5-1792 to the University of Colorado.

Brown, A.; Bromage, G.; Schmitt, J.; Ambruster, C.; Linsky, J. L.

1992-12-01

306

Wide-field two-photon microscopy: features and advantages for biomedical applications  

NASA Astrophysics Data System (ADS)

We describe a simple fluorescence microscope based on wide-field two-photon excitation. While still taking advantage of some inherent properties of non-linear (two-photon) microscopy, such as increased penetration depth through tissue and reduced phototoxicity, this approach provides video frame rate imaging, can be easily coupled to fluorescence spectral and lifetime detection modules, and makes efficient use of the high average power currently available from ultrashort pulsed lasers. For a standard histopathology specimen, we were able to identify different structures based on spectral and fluorescence lifetime detection and analysis. We examined the use of 200fs and 2ps pulses from Spectra Physics MaiTai and Tsunami lasers, respectively, with average power ranging from 50mW to 500mW.

Wachsmann-Hogiu, S.; Hwang, J. Y.; Lindsley, E.; Farkas, D. L.

2007-02-01

307

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

308

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

NASA Astrophysics Data System (ADS)

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

1990-06-01

309

Interference visibility of the wide-field-of-view polarization interference imaging spectrometer (WPIIS)  

NASA Astrophysics Data System (ADS)

Wide-field-of-view polarization interference imaging spectrometer (WPIIS) is one kind of birefringent interferometers utilized for imaging and spectroscopy. WPIIS employs polarization components (the polarizer, analyzer, the field-widened Savart polariscope and an achromatic half wave plate (AHWP) sandwiched between the two Savart plates) for interferogram acquisition. To acquire excellent reconstructed spectrum, the whole system should ensure high fringe visibility. In this work, polarization deviation and retardation deviation of polarization components are considered into the interference visibility. The resultant visibility is investigated in detail. It is shown that polarization and retardation deviations would severely degrade the final spectrum estimations. The corresponding quantitative tolerances are also provided in which cases we can get attractive visibility higher than 0.97. This work would provide actual suggestions for system design, spectroscopic estimations and performance optimization of any system composed of polarization components.

Wu, Haiying; Zhang, Sanxi; Zhang, Chunmin

2014-12-01

310

Background Simulations of the Wide Field Imager of the ATHENA X-Ray Observatory  

E-print Network

The ATHENA X-ray Observatory-IXO is a planned multinational orbiting X-ray observatory with a focal length of 11.5m. ATHENA aims to perform pointed observations in an energy range from 0.1 keV to 15 keV with high sensitivity. For high spatial and timing resolution imaging and spectroscopic observations the 640x640 pixel^2 large DePFET-technology based Wide field Imager (WFI) focal plane detector, providing a field of view of 18 arcsec will be the main detector. Based on the actual mechanics, thermal and shielding design we present estimates for the WFI cosmic ray induced background obtained by the use of Monte-Carlo simulations and possible background reduction measures.

Hauf, Steffen; Pia, Maria Grazia; Hoffmann, Dieter H H; Lang, Philipp; Neff, Stephan; Stefanescu, Alexander; Strüder, Lothar

2011-01-01

311

Wide-field fluorescence lifetime imaging with multi-anode detectors.  

PubMed

Fluorescence lifetime imaging microscopy (FLIM) has become a powerful and widely used tool to monitor inter- and intramolecular dynamics of fluorophore-labeled proteins inside living cells.Here, we present recent achievements in the construction of a positional sensitive wide-field single-photon counting detector system to measure fluorescence lifetimes in the time domain and demonstrate its usage in FRET applications.The setup is based on a conventional fluorescence microscope equipped with synchronized short-pulse lasers that illuminate the entire field of view at minimal invasive intensities, thereby enabling long-term experiments of living cells. The system is capable to acquire single-photon counting images and measures directly the transfer rate of fast photophysical processes as, for instance, FRET, in which it can resolve complex fluorescence decay kinetics. PMID:24108639

Hartig, Roland; Prokazov, Yury; Turbin, Evgeny; Zuschratter, Werner

2014-01-01

312

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

313

Current status of the Hobby-Eberly Telescope wide field upgrade  

NASA Astrophysics Data System (ADS)

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

Hill, Gary J.; Booth, John A.; Cornell, Mark E.; Good, John M.; Gebhardt, Karl; Kriel, Herman J.; Lee, Hanshin; Leck, Ron; Moreira, Walter; MacQueen, Phillip J.; Perry, Dave M.; Rafal, Marc D.; Rafferty, Tom H.; Ramiller, Chuck; Savage, Richard D.; Taylor, Charles A.; Vattiat, Brian L.; Ramsey, Lawrence W.; Beno, Joseph H.; Beets, Timothy A.; Esguerra, Jorge D.; Häuser, Marco; Hayes, Richard J.; Heisler, James T.; Soukup, Ian M.; Zierer, Joseph J.; Worthington, Michael S.; Mollison, Nicholas T.; Wardell, Douglas R.; Wedeking, Gregory A.

2012-09-01

314

T80Cam: the wide field camera for the OAJ 83-cm telescope  

NASA Astrophysics Data System (ADS)

The Observatorio Astrofísico de Javalambre (OAJ) is a new astronomical facility located at the Sierra de Javalambre (Teruel, Spain) whose primary role will be to conduct all-sky astronomical surveys. The OAJ facility will have two wide-field telescopes: the JST/T250; a 2.55-m telescope with a 3° diameter field of view (FoV), and the JAST/T80; an 0.83-m telescope with a 2° diameter FoV. First light instrumentation is being designed to exploit the survey capabilities of the OAJ telescopes. This paper describes the T80Cam, a wide-field camera that will be installed at the Cassegrain focus of the JAST/T80. It is equipped with an STA 1600 backside illuminated detector. This is a 10.5k-by-10.5k, 9?m pixel, high efficiency CCD that is read from 16 ports simultaneously, allowing read times of ~20s with a typical read noise of 6 electrons (rms). This full wafer CCD covers a large fraction of the JAST/T80's FoV with a pixel scale of ~0.50"/pixel. T80Cam will observe in the wavelength range 330-1000nm through a set of 12 carefully optimized broad-, intermediate- and narrow-band filters. The camera is intended for surveys with the JAST/T80 telescope, starting with the planned J-PLUS (Javalambre Photometric Local Universe Survey), a multi-band photometric all-sky survey that will be completed in about 2 years and will reach AB˜ 23 mag (5? level) with the SDSS filters.

Marin-Franch, A.; Taylor, K.; Cepa, J.; Laporte, R.; Cenarro, A. J.; Chueca, S.; Cristobal-Hornillos, D.; Ederoclite, A.; Gruel, N.; Hernández-Fuertes, J.; López-Sainz, A.; Luis-Simoes, R.; Moles, M.; Rueda-Teruel, F.; Rueda-Teruel, S.; Varela, J.; Yanes-Díaz, A.; Benitez, N.; Dupke, R.; Fernández-Soto, A.; Mendes de Oliveira, C.; Sims, G.; Sodré, L.; Toerne, K.

2012-09-01

315

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

316

Report on the ESO workshop 'Wide-Field Spectroscopic Surveys' held at ESO Headquarters, Germany, 10-11 March 2009  

NASA Astrophysics Data System (ADS)

The wide-field imaging surveys to be conducted with ESO VISTA and VST telescopes and with the ESA Gaia satellite demand spectroscopic follow-up. Presentations and discussions on the role of wide-field spectroscopic surveys with ESO telescopes at this dedicated workshop are summarised. The instrument requirements for spectroscopic surveys of large-scale galaxy structure, fundamental cosmology, and the structure of the Milky Way and its neighbourhood are presented.

Melnick, Jorge; Mellier, Yannick; Pasquini, Luca; Leibundgut, Bruno

2009-06-01

317

Ray tracing simulations for the wide-field x-ray telescope of the Einstein Probe mission based on Geant4 and XRTG4  

NASA Astrophysics Data System (ADS)

Einstein Probe (EP) is a proposed small scientific satellite dedicated to time-domain astrophysics working in the soft X-ray band. It will discover transients and monitor variable objects in 0.5-4 keV, for which it will employ a very large instantaneous field-of-view (60° × 60°), along with moderate spatial resolution (FWHM ˜ 5 arcmin). Its wide-field imaging capability will be achieved by using established technology in novel lobster-eye optics. In this paper, we present Monte-Carlo simulations for the focusing capabilities of EP's Wide-field X-ray Telescope (WXT). The simulations are performed using Geant4 with an X-ray tracer which was developed by cosine (http://cosine.nl/) to trace X-rays. Our work is the first step toward building a comprehensive model with which the design of the X-ray optics and the ultimate sensitivity of the instrument can be optimized by simulating the X-ray tracing and radiation environment of the system, including the focal plane detector and the shielding at the same time.

Zhao, Donghua; Zhang, Chen; Yuan, Weimin; Willingale, Richard; Ling, Zhixing; Feng, Hua; Li, Hong; Ji, Jianfeng; Wang, Wenxin; Zhang, Shuangnan

2014-07-01

318

Wide field array calibration dependence on the stability of measured dose distributions  

SciTech Connect

Purpose: The aim of this work was to simulate the effect of dose distribution changes on detector array calibrations and to explore compensatory methods that are used during calibration measurements. Methods: The array calibration technique that was investigated is known as wide field (WF) calibration. Using this method, a linear array [y-axis (65 detectors) of the IC PROFILER (Sun Nuclear Corporation, Melbourne, FL)] is calibrated with three measurements ({alpha}, {theta}, and {lambda}); each measurement uses the same radiation field, which is larger than the array. For measurement configuration {theta}, the array is rotated by 180 deg. from its position in {alpha}; for {lambda}, the array is shifted by one detector from its position in {theta}. The relative detector sensitivities are then determined through ratios of detector readings at the same field locations (using {theta} and {lambda}). This method results in error propagation that is proportional to the number of detectors in the array. During the procedure, the calibration protocol operates under three postulates, which state that (a) the beam shape does not change between measurements; (b) the relative sensitivities of the detectors do not change; and (c) the scatter to the array does not change as the array is moved. The WF calibration's sensitivity to a postulate (a) violation was quantified by applying a sine shaped perturbation (of up to 0.1%) to {alpha}, {theta}, or {lambda}, and then determining the change relative to a baseline calibration. Postulate (a) violations were minimized by using a continuous beam and mechanized array movement during {theta} and {lambda}. A continuously on beam demonstrated more stable beam symmetry as compared to cycling the beam on and off between measurements. Additional side-scatter was also used to satisfy postulate (c). Results: Simulated symmetry perturbations of 0.1% to {theta} or {lambda} resulted in calibration errors of up to 2%; {alpha} was relatively immune to perturbation (<0.1% error). Wide field calibration error on a linear accelerator with similar symmetry variations was {+-}1.6%. Using a continuous beam during {theta} and {lambda} with additional side-scatter reduced the calibration error from {+-}1.6% to {+-}0.48%. Conclusions: This work increased the reproducibility of WF calibrations by limiting the effect of measurement perturbations primarily due to linear accelerator symmetry variations. The same technique would work for any array using WF calibration.

Simon, Thomas A.; Simon, William E.; Kahler, Darren; Li, Jonathan; Liu, Chihray [Department of Nuclear and Radiological Engineering, University of Florida, 202 Nuclear Science Building, Gainesville, Florida 32611-8300, Department of Radiation Oncology, Health Science Center, University of Florida, P.O. Box 100385, Gainesville, Florida 32610-0385, and Sun Nuclear Corporation, 425-A Pineda Court, Melbourne, Florida 32940 (United States); Sun Nuclear Corporation, 425-A Pineda Court, Melbourne, Florida 32940 (United States); Department of Radiation Oncology, Health Science Center, University of Florida, P.O. Box 100385, Gainesville, Florida 32610-0385 (United States)

2010-07-15

319

Mid-infrared Variability from the Spitzer Deep Wide-field Survey  

NASA Astrophysics Data System (ADS)

We use the multi-epoch, mid-infrared Spitzer Deep Wide-Field Survey to investigate the variability of objects in 8.1 deg2 of the NOAO Deep Wide Field Survey Boötes field. We perform a Difference Image Analysis of the four available epochs between 2004 and 2008, focusing on the deeper 3.6 and 4.5 ?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 (?12) exceeds that for all sources with the same magnitude by 2?. We then examine the mid-IR colors of the variable sources and match them with X-ray sources from the XBoötes survey, radio catalogs, 24 ?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 ?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 ? ? 0.5 at both 3.6 and 4.5 ?m, and an amplitude of S 0 ~= 0.1 mag on rest-frame timescales of 2 yr. The variability amplitude is higher for shorter rest-frame wavelengths and lower luminosities.

Koz?owski, Szymon; Kochanek, Christopher S.; Stern, Daniel; Ashby, Matthew L. N.; Assef, Roberto J.; Bock, J. J.; Borys, C.; Brand, K.; Brodwin, M.; Brown, M. J. I.; Cool, R.; Cooray, A.; Croft, S.; Dey, Arjun; Eisenhardt, P. R.; Gonzalez, A.; Gorjian, V.; Griffith, R.; Grogin, N.; Ivison, R.; Jacob, J.; Jannuzi, B. T.; Mainzer, A.; Moustakas, L.; Röttgering, H.; Seymour, N.; Smith, H. A.; Stanford, S. A.; Stauffer, J. R.; Sullivan, I. S.; van Breugel, W.; Willner, S. P.; Wright, E. L.

2010-06-01

320

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

321

Simulation of optical response of retroreflectors for future lunar laser ranging  

NASA Astrophysics Data System (ADS)

We numerically examined various retroreflectors as laser ranging targets for future missions to the Moon. The geometric conditions, such as the angle of incidence and velocity aberration, with lunar targets are much more restricted than those with most of the earth-orbiting artificial satellites. The numerical optical response simulation carried out in this study indicates that a single retroreflector with a diameter of 150-250 mm performs similar to the existing Apollo retroreflector arrays. Further, no dihedral angle is required for small retroreflectors with diameters below 150 mm for uncoated ones and below 100 mm for coated and hollow ones. Retroreflectors with larger diameters require dihedral angles of 0.20, 0.25, and 0.35 arcsec for coated, uncoated and hollow types, respectively. The objective of this fundamental study is to underlie the development of future laser ranging targets that are to be placed on the Moon.

Otsubo, Toshimichi; Kunimori, Hiroo; Noda, Hirotomo; Hanada, Hideo

2010-03-01

322

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

323

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

324

The Discovery of Y Dwarfs Using Data from the Wide-field Infrared Survey Explorer (WISE)  

E-print Network

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_2O and CH_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_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_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 J0722-0540 as the T9 spectral standard and tentatively assign WISEP J173835.52+273258.9 as the Y0 spect...

Cushing, Michael C; Gelino, Christopher R; Griffith, Roger L; Skrutskie, Michael F; Mainzer, Amanda K; Marsh, Kenneth A; Beichman, Charles A; Burgasser, Adam J; Prato, Lisa A; Simcoe, Robert A; Marley, Mark S; Saumon, D; Freedman, Richard S; Eisenhardt, Peter R; Wright, Edward L

2011-01-01

325

A TECHNIQUE FOR PRIMARY BEAM CALIBRATION OF DRIFT-SCANNING, WIDE-FIELD ANTENNA ELEMENTS  

SciTech Connect

We present a new technique for calibrating the primary beam of a wide-field, drift-scanning antenna element. Drift-scan observing is not compatible with standard beam calibration routines, and the situation is further complicated by difficult-to-parameterize beam shapes and, at low frequencies, the sparsity of accurate source spectra to use as calibrators. We overcome these challenges by building up an interrelated network of source 'crossing points'-locations where the primary beam is sampled by multiple sources. Using the single assumption that a beam has 180 Degree-Sign rotational symmetry, we can achieve significant beam coverage with only a few tens of sources. The resulting network of crossing points allows us to solve for both a beam model and source flux densities referenced to a single calibrator source, circumventing the need for a large sample of well-characterized calibrators. We illustrate the method with actual and simulated observations from the Precision Array for Probing the Epoch of Reionization.

Pober, Jonathan C.; Parsons, Aaron R. [Astronomy Department, University of California, Berkeley, CA (United States); Jacobs, Daniel C. [School of Earth and Space Exploration, Arizona State University, Tempe, AZ (United States); Aguirre, James E.; Moore, David F. [Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA (United States); Bradley, Richard F.; Parashare, Chaitali R. [Department of Electrical and Computer Engineering, University of Virginia, Charlottesville, VA (United States); Carilli, Chris L. [National Radio Astronomy Observatory, Socorro, NM (United States); Gugliucci, Nicole E. [Department of Astronomy, University of Virginia, Charlottesville, VA (United States)

2012-02-15

326

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

327

Living life on the edge - Wide-field VLBI at 90 cm!  

E-print Network

We report on a recent 90 cm wide-field VLBI survey of two 3.1 deg^2 fields using the VLBA, Westerbork and Jodrell Bank telescopes. In-beam calibration was used to calibrate each field, the process was simplified by imaging the calibrators in DIFMAP and transferring the calibration solutions to AIPS using the newly developed DIFMAP task - cordump. We detected and imaged 13 out of the 141 sources originally detected by the low resolution (54") WENSS survey of the same two fields. The sources were detected at 7-12 sigma levels above the image noise, had total flux densities ranging between 85-1640 mJy and were between 16'-58' from the phase centre of each field. This is the first systematic (and non-biased), deep, high resolution survey of the low frequency radio sky. These initial results suggest that new instruments such as LOFAR should detect many compact radio sources and that plans to extend these arrays to baselines of several thousand kilometres are warranted.

Emil Lenc; Mike A. Garrett; Olaf Wucknitz; James M. Anderson; Steven J. Tingay

2006-12-21

328

LAIWO: a new wide-field CCD camera for Wise Observatory  

NASA Astrophysics Data System (ADS)

LAIWO is a new CCD wide-field camera for the 40-inch Ritchey-Chretien telescope at Wise Observatory in Mitzpe Ramon/Israel. The telescope is identical to the 40-in. telescope at Las Campanas Observatory, Chile, which is described in [2]. LAIWO was designed and built at Max-Planck-Institute for Astronomy in Heidelberg, Germany. The scientific aim of the instrument is to detect Jupiter-sized extra-solar planets around I=14-15 magnitude stars with the transit method, which relies on the temporary drop in brightness of the parent star harboring the planet. LAIWO can observe a 1.4 x 1.4 degree field-of-view and has four CCDs with 4096*4096 pixels each The Fairchild Imaging CCDs have a pixel size of 15 microns. Since they are not 2-side buttable, they are arranged with spacings between the chips that is equal to the size of a single CCD minus a small overlap. The CCDs are cooled by liquid nitrogen to a temperature of about -100 °C. The four science CCDs and the guider CCD are mounted on a common cryogenic plate which can be adjusted in three degrees of freedom. Each of these detectors can also be adjusted independently by a similar mechanism. The instrument contains large shutter and filter mechanisms, both designed in a modular way for fast exchange and easy maintenance.

Baumeister, Harald; Afonso, Cristina; Marien, Karl-Heinz; Klein, Ralf

2006-06-01

329

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

E-print Network

We present a revised effective wavelength and photometric calibration for the Wide-field Infrared Survey Explorer (WISE) 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 micron to 22.8 micron, and the W4 AB magnitude of Vega should be revised from m = 6.59 to m = 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 micron. Of the three relative system response curve...

Brown, M J I; Cluver, M E

2014-01-01

330

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

331

Wide-field VLBA Observations of the Chandra Deep Field South  

E-print Network

Wide-field surveys are a commonly-used method for studying thousands of objects simultaneously, to investigate, e.g., the joint evolution of star-forming galaxies and active galactic nuclei. VLBI observations can yield valuable input to such studies because they are able to identify AGN. However, VLBI observations of large swaths of the sky are impractical using standard methods, because the fields of view of VLBI observations are of the order of 10" or less. We have embarked on a project to carry out Very Long Baseline Array (VLBA) observations of all 96 known radio sources in one of the best-studied areas in the sky, the Chandra Deep Field South (CDFS). The challenge was to develop methods which could significantly reduce the amount of observing (and post-processing) time. We have developed an extension to the DiFX software correlator which allows one to correlate hundreds of positions within the primary beams. This extension enabled us to target many sources, at full resolution and high sensitivity, using ...

Middelberg, Enno; Morgan, John; Rottmann, Helge; Alef, Walter; Tingay, Steven; Norris, Ray; Bach, Uwe; Brisken, Walter; Lenc, Emil

2010-01-01

332

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

333

The First Ultra-Cool Brown Dwarf Discovered by the Wide-field Infrared Survey Explorer  

E-print Network

We report the discovery of the first new ultra-cool brown dwarf 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 micron 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 brown dwarf is easily detected by WISE, with a signal-to-noise ratio of ~36 at 4.6 microns. Current estimates place it at a distance of 6 to 10 pc. This object represents the first in what will likely be hundreds of nearby brown dwarfs 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, ...

Mainzer, A; Skrutskie, M; Gelino, C R; Kirkpatrick, J Davy; Jarrett, T; Masci, F; Marley, M; Saumon, D; Wright, E; Beaton, R; Dietrich, M; Eisenhardt, P; Garnavich, P; Kuhn, O; Leisawitz, D; Marsh, K; McLean, I; Padgett, D; Rueff, K

2010-01-01

334

Electrolocation-based underwater obstacle avoidance using wide-field integration methods.  

PubMed

Weakly electric fish are capable of efficiently performing obstacle avoidance in dark and navigationally challenging aquatic environments using electrosensory information. This sensory modality enables extraction of relevant proximity information about surrounding obstacles by interpretation of perturbations induced to the fish's self-generated electric field. In this paper, reflexive obstacle avoidance is demonstrated by extracting relative proximity information using spatial decompositions of the perturbation signal, also called an electric image. Electrostatics equations were formulated for mathematically expressing electric images due to a straight tunnel to the electric field generated with a planar electro-sensor model. These equations were further used to design a wide-field integration based static output feedback controller. The controller was implemented in quasi-static simulations for environments with complicated geometries modelled using finite element methods to demonstrate sense and avoid behaviours. The simulation results were confirmed by performing experiments using a computer operated gantry system in environments lined with either conductive or non-conductive objects acting as global stimuli to the field of the electro-sensor. The proposed approach is computationally inexpensive and readily implementable, making underwater autonomous navigation in real-time feasible. PMID:24451219

Dimble, Kedar D; Faddy, James M; Humbert, J Sean

2014-03-01

335

Toward Epoch of Reionization Measurements with Wide-Field Radio Observations  

E-print Network

This paper explores the potential for statistical epoch of reionization (EOR) measurements using wide field radio observations. New developments in low frequency radio instrumentation and signal processing allow very sensitive EOR measurements, and the analysis techniques enabled by these advances offer natural ways of separating the EOR signal from the residual foreground emission. This paper introduces the enabling technologies and proposes an analysis technique designed to make optimal use of the capabilities of next generation low frequency radio arrays. The observations we propose can directly observe the power spectrum of the EOR using relatively short observations, and are significantly more sensitive than other techniques which have been discussed in the literature. For example, in the absence of foreground contamination the measurements we propose would produce five 3-sigma power spectrum points in 100 hours of observation with only 4 MHz bandwidth with LOFAR for simple models of the high redshift 21cm emission. The challenge of residual foreground removal may be addressed by the symmetries in the three-dimensional (two spatial frequencies and radiofrequency) radio interferometric data. These symmetries naturally separate the EOR signal from most classes of residual un-subtracted foreground contamination, including all foreground continuum sources and radio line emission from the Milky Way.

Miguel F. Morales; Jacqueline Hewitt

2003-12-17

336

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

337

Atmospheric Characterization of 5 Hot Jupiters with Wide Field Camera 3 on the Hubble Space Telescope  

E-print Network

We probe the structure and composition of the atmospheres of 5 hot Jupiter exoplanets using the Hubble Space Telescope Wide Field Camera 3 (WFC3) instrument. We use the G141 grism (1.1-1.7 $\\mu$m) to study TrES-2b, TrES-4b, and CoRoT-1b in transit, TrES-3b in secondary eclipse, and WASP-4b in both. This wavelength region includes a predicted absorption feature from water at 1.4 $\\mu$m, which we expect to be nondegenerate with the other molecules that are likely to be abundant for hydrocarbon-poor (e.g. solar composition) hot Jupiter atmospheres. We divide our wavelength regions into 10 bins. For each bin we produce a spectrophotometric light curve spanning the time of transit and/or eclipse. We correct these light curves for instrumental systematics without reference to an instrument model. For our transmission spectra, our mean $1-\\sigma$ precision per bin corresponds to variations of 2.1, 2.8, and 3.0 atmospheric scale heights for TrES-2b, TrES-4b, and CoRoT-1b, respectively. We find featureless spectra for...

Ranjan, Sukrit; Désert, Jean-Michel; Madhusudhan, Nikku; Deming, Drake; Wilkins, Ashlee; Mandell, Avi M

2014-01-01

338

Single plane illumination module and micro-capillary approach for a wide-field microscope.  

PubMed

A module for light sheet or single plane illumination microscopy (SPIM) is described which is easily adapted to an inverted wide-field microscope and optimized for 3-dimensional cell cultures, e.g., multi-cellular tumor spheroids (MCTS). The SPIM excitation module shapes and deflects the light such that the sample is illuminated by a light sheet perpendicular to the detection path of the microscope. The system is characterized by use of a rectangular capillary for holding (and in an advanced version also by a micro-capillary approach for rotating) the samples, by synchronous adjustment of the illuminating light sheet and the objective lens used for fluorescence detection as well as by adaptation of a microfluidic system for application of fluorescent dyes, pharmaceutical agents or drugs in small quantities. A protocol for working with this system is given, and some technical details are reported. Representative results include (1) measurements of the uptake of a cytostatic drug (doxorubicin) and its partial conversion to a degradation product, (2) redox measurements by use of a genetically encoded glutathione sensor upon addition of an oxidizing agent, and (3) initiation and labeling of cell necrosis upon inhibition of the mitochondrial respiratory chain. Differences and advantages of the present SPIM module in comparison with existing systems are discussed. PMID:25146321

Bruns, Thomas; Schickinger, Sarah; Schneckenburger, Herbert

2014-01-01

339

New observational techniques and analysis tools for wide field CCD surveys and high resolution astrometry  

E-print Network

(Abridged) In the first part of this thesis, a general methodology for applying image deconvolution to wide-field CCD imagery. Results show that wavelet-based deconvolution can increase limiting magnitude up to 0.6 mag and improve limiting resolution 1 pixel with respect to original image with no astrometric accuracy degradation. In the second part, a new observational technique based on CCD fast drift scanning has been proposed for lunar occultations (LO) and speckle interferometry. This enables all kind of professional and high-end amateur observatories to perform such kind of observations. For LO, 16 new binaries up to 2mas of projected separation were detected and stellar diameters measurements in the 7 mas regime were obtained with that CCD and IR subarray based techniques. A new wavelet-based LO reduction pipeline was implemented. For speckle, CCD fast drift scanning technique was validated with the observation of four binary systems with well determined orbits. The results of separation, position angle and magnitude difference are in accordance with published measurements. A new approach for calibrating speckle transfer function from the binary power spectrum itself has been introduced. It does not require point source observations, which gives a more effective use of observation time.

O. Fors

2006-04-06

340

Calibration of HST wide field camera for quantitative analysis of faint galaxy images  

NASA Technical Reports Server (NTRS)

We present the methods adopted to optimize the calibration of images obtained with the Hubble Space Telescope (HST) Wide Field Camera (WFC) (1991-1993). Our main goal is to improve quantitative measurement of faint images, with special emphasis on the faint (I approximately 20-24 mag) stars and galaxies observed as a part of the Medium-Deep Survey. Several modifications to the standard calibration procedures have been introduced, including improved bias and dark images, and a new supersky flatfield obtained by combining a large number of relatively object-free Medium-Deep Survey exposures of random fields. The supersky flat has a pixel-to-pixel rms error of about 2.0% in F555W and of 2.4% in F785LP; large-scale variations are smaller than 1% rms. Overall, our modifications improve the quality of faint images with respect to the standard calibration by about a factor of five in photometric accuracy and about 0.3 mag in sensitivity, corresponding to about a factor of two in observing time. The relevant calibration images have been made available to the scientific community.

Ratnatunga, Kavan U.; Griffiths, Richard E.; Casertano, Stefano; Neuschaefer, Lyman W.; Wyckoff, Eric W.

1994-01-01

341

EXOPLANETS FROM THE ARCTIC: THE FIRST WIDE-FIELD SURVEY AT 80 Degree-Sign N  

SciTech Connect

Located within 10 Degree-Sign of the North Pole, northern Ellesmere Island offers continuous darkness in the winter months. This capability can greatly enhance the detection efficiency of planetary transit surveys and other time domain astronomy programs. We deployed two wide-field cameras at 80 Degree-Sign N, near Eureka, Nunavut, for a 152 hr observing campaign in 2012 February. The 16 megapixel camera systems were based on commercial f/1.2 lenses with 70 mm and 42 mm apertures, and they continuously imaged 504 and 1295 deg{sup 2}, respectively. In total, the cameras took over 44,000 images and produced better than 1% precision light curves for approximately 10,000 stars. We describe a new high-speed astrometric and photometric data reduction pipeline designed for the systems, test several methods for the precision flat fielding of images from very-wide-angle cameras, and evaluate the cameras' image qualities. We achieved a scintillation-limited photometric precision of 1%-2% in each 10 s exposure. Binning the short exposures into 10 minute chunks provided a photometric stability of 2-3 mmag, sufficient for the detection of transiting exoplanets around the bright stars targeted by our survey. We estimate that the cameras, when operated over the full Arctic winter, will be capable of discovering several transiting exoplanets around bright (m{sub V} < 9.5) stars.

Law, Nicholas M.; Sivanandam, Suresh [Dunlap Institute for Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, Ontario M5S 3H4 (Canada); Carlberg, Raymond; Salbi, Pegah; Ngan, Wai-Hin Wayne; Kerzendorf, Wolfgang [Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, Ontario M5S 3H4 (Canada); Ahmadi, Aida [University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4 (Canada); Steinbring, Eric; Murowinski, Richard, E-mail: law@di.utoronto.ca [National Science Infrastructure, National Research Council Canada, Victoria, British Columbia, V9E 2E7 (Canada)

2013-03-15

342

Automatic vessel segmentation in wide-field retina images of infants with retinopathy of prematurity.  

PubMed

The earliest signs of Retinopathy of Prematurity (ROP) are tortuosity and dilation of retinal vessels. Such vascular changes are considered of primary importance for the diagnosis and the follow-up of the disease. However, a widely accepted computerized system for their quantitative measurement is still missing. Images taken from a preterm baby's eye are often low-contrast, noisy, and blurred. Algorithms that have been successfully applied to analyze adult retinal images do not work well in ROP images. We propose here a novel method for the automatic extraction of vessel centerline in wide-field ROP retinal images, based on a sparse tracking scheme. After a set of seed points is identified all over the image, vessels are traced by connecting those seeds by means of minimum cost paths, whose weights depend on similarity features and alignment evaluated by a custom line operator. The performance of the method was assessed on a dataset of 20 images acquired with the RetCam fundus camera. A sensitivity of 0.78 and a false detection rate of 0.15 were obtained with respect to manual ground truth reference. PMID:22255205

Poletti, Enea; Fiorin, Diego; Grisan, Enrico; Ruggeri, Alfredo

2011-01-01

343

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

344

The DECam NEO Survey: A sensitive, wide-field search for near-Earth asteroids  

NASA Astrophysics Data System (ADS)

We report preliminary results from a survey for near-Earth asteroids with the Dark Energy Camera. DECam is a facility-class 520 Megapixel wide-field imager on the 4m Blanco telescope at Cerro Tololo Inter-american Observatory. It has a 3.2 square degree field of view, and a focal plane consisting of 62 2Kx4K red-optimized CCDs. In spite of its large number of pixels, DECam reads out in less than 30 seconds, making it possible to cover a large area of sky efficiently. Compared to the largest aperture of the currently most productive NEO searches, the Blanco has an aperture that is several times larger and a comparable field of view. Our goal is to measure the size distribution of NEOs well below 140m, and we have been allocated 30 nights through the NOAO Survey program to achieve it. Here we report on results from the first 10 nights of our survey.

Allen, Lori; Trilling, David; Valdes, Frank; Fuentes, Cesar; James, David; Herrera, David; Rajagopal, Jayadev; Burt, Brian; Axelrod, Tim

2014-11-01

345

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

346

The First Ultra-cool Brown Dwarf Discovered by the Wide-field Infrared Survey Explorer  

NASA Astrophysics Data System (ADS)

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 ?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 ~36 at 4.6 ?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.; Skrutskie, M.; Gelino, C. R.; Kirkpatrick, J. Davy; Jarrett, T.; Masci, F.; Marley, Mark S.; Saumon, D.; Wright, E.; Beaton, R.; Dietrich, M.; Eisenhardt, P.; Garnavich, P.; Kuhn, O.; Leisawitz, D.; Marsh, K.; McLean, I.; Padgett, D.; Rueff, K.

2011-01-01

347

Exoplanets from the Arctic: The First Wide-Field Survey at 80 Degrees North  

E-print Network

Located within 10 degrees 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 degrees North, near Eureka, Nunavut, for a 152-hour observing campaign in February 2012. The 16-megapixel-camera systems were based on commercial f/1.2 lenses with 70mm and 42mm apertures, and they continuously imaged 504 and 1,295 square degrees 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 10s exposure. Binning th...

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

2012-01-01

348

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

349

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

350

First flight of ProtoEXIST: High Resolution, Wide-Field, Hard X-ray Imaging  

NASA Astrophysics Data System (ADS)

The ProtoEXIST program had its first balloon flight from Ft. Sumner, NM, Oct. 9, 2009. The first generation hard X-ray (20 -600 keV) wide-field (20 x 20 deg) imager, ProtoEXIST1, is a 16 x 16cm array of 2 x 2 x 0.5cm Cd-Zn-Te (CZT) detectors, each with an 8 x 8 array of 2.5mm pixels, and close-tiled (0.6mm gaps) into a continuous array with all readout electronics "vertically integrated" below. The detector plane is shielded and images the sky through a coded aperture mask, constructed from laminating etched Tungsten sheets, and enabling imaging with 18arcmin resolution. The detector and telescope and newly refurbished Harvard-MSFC gondola performed well on this short (6h) flight, obtaining an image of a bright source (Cyg X-1) in a relatively short exposure. Details of the instrument, associated gondola and control systems, and the development program now underway to build and fly ProtoEXIST2, a comparable imaging area but with 4X smaller pixel size (0.6mm) as needed for the proposed EXIST satellite mission, will be presented.

Grindlay, Jonathan; Barthelmy, Scott; Ramsey, Brian

351

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

352

Parallax beyond a Kiloparsec from Spatially Scanning the Wide Field Camera 3 on the Hubble Space Telescope  

NASA Astrophysics Data System (ADS)

We use a newly developed observing mode on the Hubble Space Telescope (HST) and Wide Field Camera 3, spatial scanning, to increase source sampling a thousand-fold and measure changes in source positions to a precision of 20-40 ?as, more than an order of magnitude better than attainable in pointed observations. This observing mode can usefully measure the parallaxes of bright stars at distances of up to 5 kpc, a factor of 10 farther than achieved thus far with HST. The technique should also provide a unique crosscheck of future parallax measurements from Gaia. Long-period classical Cepheid variable stars in the Milky Way, nearly all of which reside beyond 1 kpc, are especially compelling targets for parallax measurements from scanning, as they may be used to anchor a determination of the Hubble constant to ~1%. We illustrate the method by measuring to high precision the parallax of a classical Cepheid, SY Aurigae, at a distance of more than 2 kpc, using five epochs of spatial-scan data obtained at intervals of six months. Rapid spatial scans also enable photometric measurements of bright Milky Way Cepheids—which would otherwise saturate even in the shortest possible pointed observations—on the same flux scale as extragalactic Cepheids, which is a necessity for reducing a leading source of systematic error in the Hubble constant. We demonstrate this capability with photometric measurements of SY Aur on the same system used for Cepheids in Type Ia supernova host galaxies. While the technique and results presented here are preliminary, an ongoing program with HST is collecting such parallax measurements for another 18 Cepheids to produce a better anchor for the distance scale. 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.; Casertano, Stefano; Anderson, Jay; MacKenty, John; Filippenko, Alexei V.

2014-04-01

353

Wide-field, surface-sensitive four-wave mixing microscopy of nanostructures  

E-print Network

, however, to extend the ver- satility of FWM techniques to the research area of mo- lecules and structures techniques to surface-specific spectroscopy and chemical sensing, especially in the area of microscopy. One/163305-08$15.00/0 © 2012 Optical Society of America 1 June 2012 / Vol. 51, No. 16 / APPLIED OPTICS 3305 #12;of molecules

354

MIT Lincoln Laboratory has demonstrated the first digital, wide field-of-view  

E-print Network

for the Defense Advanced Research Projects Agency's (DARPA) Space Surveillance Telescope (SST), a new, very wide is a worldwide network of radars and optical telescopes that provides tracking and custody of resident space objects. Ground-based optical telescope sites are the backbone of U.S. surveillance of so-called deep-space

355

Prenatal determinants of optic nerve hypoplasia: review of suggested correlates and future focus.  

PubMed

Optic nerve hypoplasia (ONH), a congenital malformation characterized by an underdeveloped optic nerve, is a seemingly epidemic cause of childhood blindness and visual impairment with associated lifelong morbidity. Although the prenatal determinants of ONH are unknown, early case reports have led to a longstanding speculation that risky health behaviors (e.g., prenatal use of recreational drugs, alcohol) are a likely culprit. There has yet to be a systematic review of the epidemiology of ONH to assess the common prenatal features that may help focus research efforts in the identification of likely prenatal correlates. A review of the past 50 years of epidemiologic research was conducted to examine the prenatal features linked with ONH and provide direction for future research. There are select prominent prenatal features associated with ONH: young maternal age and primiparity. Commonly implicated prenatal exposures (recreational or pharmaceutical drugs, viral infection, etc.) were rare or uncommon in large cohort studies of ONH and therefore unlikely to be major contributors to ONH. Familial cases and gene mutations are rare. The preponderance of young mothers and primiparity among cases of ONH is striking, although the significance is unclear. Recent research suggests a potential role for prenatal nutrition, weight gain, and factors of deprivation. With the rapidly increasing prevalence of ONH, future research should focus on investigating the relevance of young maternal age and primiparity and exploring the recently suggested etiologic correlates in epidemic clusters of ONH. PMID:24160732

Garcia-Filion, Pamela; Borchert, Mark

2013-01-01

356

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

357

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

358

Wide Field Hard X-ray Survey Telescope: ProtoEXIST1  

E-print Network

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.

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

2007-09-17

359

Improved Infrared Focal Plane Arrays for HST/Wide Field Camera 3  

NASA Astrophysics Data System (ADS)

Wide Field Camera 3 is a powerful UV/visible/near-IR imager currently in development for installation into the Hubble Space Telescope. The IR channel of the instrument covers the wavelength range from 800 to 1700nm and will provide HST with a powerful capability for studying high-redshift galaxies, high-redshift Type Ia supernova "standard candles", star formation regions, and planetary atmospheres. At the heart of the IR channel is a custom HgCdTe focal plane array (1024 x 1024 pixels) developed by Rockwell Science Center. A high-quality array has been packaged for flight and has demonstrated good performance in thermal-vacuum test. However, as described in the accompanying poster by Hill et al., we have discovered a radiation-induced luminescence phenomenon in the CdZnTe substrates on which the HgCdTe detection layers are grown; in the orbital radiation environment, the resulting background could potentially be strong enough to affect the sensitivity of WFC3 observations. Fortunately, Rockwell is now capable of manufacturing high-quality HgCdTe arrays with the offending substrate removed. Hence, the WFC3 program is currently procuring new substrate-removed arrays to eliminate the radiation-induced background risk. Testing of the new arrays demonstrates that they exhibit greatly improved quantum efficiency performance vs. the original flight device. We report here on the performance of the new IR arrays in development for WFC3, present the sensitivity improvement that can be anticipated for the instrument, and describe the processing flow for getting a new flight array packaged and integrated for launch.

Kimble, R. A.; MacKenty, J. W.; Hill, R. J.; Robberto, M.; Delo, G.; Foltz, R.; Malumuth, E. M.; Reed, S.; Russell, A. M.; Waczynski, A.; Wen, Y.; Figer, D.; WFC3 Team

2005-12-01

360

Wide-field kinematics of globular clusters in the Leo I group  

E-print Network

We present wide-field spectroscopy of globular clusters around the Leo I group galaxies NGC 3379 and NGC 3384 using the FLAMES multi-fibre instrument at the VLT. We obtain accurate radial velocities for 42 globular clusters (GCs) in total, 30 for GCs around the elliptical NGC 3379, eight around the lenticular NGC 3384, and four which may be associated with either galaxy. These data are notable for their large radial range extending from 0'7 to 14'5 (2 to 42 kpc) from the centre of NGC 3379, and small velocity uncertainties of about 10 km/s. We combine our sample of 30 radial velocities for globular clusters around NGC 3379 with 8 additional GC velocities from the literature, and find a projected velocity dispersion of 175(+24/-22) km/s at R 5'. These velocity dispersions are consistent with a dark matter halo around NGC 3379 with a concentration in the range expected from a LCDM cosmological model and a total mass of ~ 6 x 10^11 Msun. Such a model is also consistent with the stellar velocity dispersion at small radii and the rotation of the HI ring at large radii, and has a M/L_B that increases by a factor of five from several kpc to 100 kpc. Our velocity dispersion for the globular cluster system of NGC 3379 is somewhat higher than that found for the planetary nebulae (PNe) in the inner region covered by the PN data, and we discuss possible reasons for this difference. For NGC 3384, we find the GC system has a rotation signature broadly similar to that seen in other kinematic probes of this SB0 galaxy. This suggests that significant rotation may not be unusual in the GC systems of disc galaxies.

G. Bergond; S. E. Zepf; A. J. Romanowsky; R. M. Sharples; K. L. Rhode

2005-11-16

361

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

362

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

363

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

364

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

365

A new x-ray optics laboratory (XROL) at the ALS: mission, arrangement, metrology capabilities, performance, and future plans  

NASA Astrophysics Data System (ADS)

The X-Ray Optics Laboratory (XROL) at the Advanced Light Source (ALS), a unique optical metrology lab, has been recently moved to a new, dedicated clean-room facility that provides improved environmental and instrumental conditions vitally required for high accuracy metrology with state-of-the-art X-ray optics. Besides the ALS, the XROL serves several DOE labs that lack dedicated on-site optical metrology capabilities, including the Linac Coherent Light Source (LCLS) at SLAC and LBNL's Center for X-Ray Optics (CXRO). The major role of XROL is to proactively support the development and optimal beamline use of x-ray optics. The application of different instruments available in the lab enables separate, often complementary, investigations and addresses of different potential sources of error affecting beamline performance. At the beamline, all the perturbations combine to produce a cumulative effect on the performance of the optic that makes it difficult to optimize the optic's operational performance. Ex situ metrology allows us to address the majority of the problems before the installation of the optic at a beamline, and to provide feedback on design and guidelines for the best usage of optics. We will review the ALS XROL mission, lab design and arrangement, ex situ metrology capabilities and performance, as well as the future plans for instrumentation upgrades. The discussion will be illustrated with the results of a broad spectrum of measurements of x-ray optics and optical systems performed at the XROL.

Yashchuk, Valeriy V.; Artemiev, Nikolay A.; Lacey, Ian; McKinney, Wayne R.; Padmore, Howard A.

2014-09-01

366

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

367

Systems, computer-implemented methods, and tangible computer-readable storage media for wide-field interferometry  

NASA Technical Reports Server (NTRS)

Disclosed herein are systems, computer-implemented methods, and tangible computer-readable storage media for wide field imaging interferometry. The method includes for each point in a two dimensional detector array over a field of view of an image: gathering a first interferogram from a first detector and a second interferogram from a second detector, modulating a path-length for a signal from an image associated with the first interferogram in the first detector, overlaying first data from the modulated first detector and second data from the second detector, and tracking the modulating at every point in a two dimensional detector array comprising the first detector and the second detector over a field of view for the image. The method then generates a wide-field data cube based on the overlaid first data and second data for each point. The method can generate an image from the wide-field data cube.

Lyon, Richard G. (Inventor); Leisawitz, David T. (Inventor); Rinehart, Stephen A. (Inventor); Memarsadeghi, Nargess (Inventor)

2012-01-01

368

Fluidic zoom-lens-on-a-chip with wide field-of-view tuning range  

Microsoft Academic Search

Integrated fluidic zoom-lens-on-a-chip with 5-mm lens aperture and less than 18-mm optical system physical length was demonstrated. The device was fabricated using standard microfabrication process. The zooming capability was achieved via focal length tuning instead of varying the lens distance. Zoom lens, telephoto, and reverse telephoto optical systems can be functionally integrated into one system on a chip without any

De-Ying Zhang; Nicole Justis; Yu-Hwa Lo

2004-01-01

369

Axial resolution for two-photon wide-field illumination microscopy and microfabrication  

Microsoft Academic Search

For the last two decades, multiphoton excitation microscopy\\/microfabrication based on laser scanning\\/writing techniques has been popular in the life science as well as photonics. Due to the slow scanning\\/writing nature, these applications are very limited to the production of prototypes, although its submicron optical resolution and intrinsic 3D optical sectioning capability are very attractive for creating 3D structures. In this

Daekeun Kim; Peter So

2008-01-01

370

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

PubMed

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

2010-05-01

371

DEEP, WIDE-FIELD CCD PHOTOMETRY FOR THE OPEN CLUSTER NGC 3532  

SciTech Connect

We present the results of a deep, wide-field CCD survey for the open cluster NGC 3532. Our new BV(RI){sub c} photometry effectively covers a one square degree area and reaches an unprecedented depth of V {approx} 21 to reveal that NGC 3532 is a rich open cluster that harbors a large number of faint, low-mass stars. We employ a number of methods to reduce the impact of field star contamination in the cluster color-magnitude diagrams (CMDs), including supplementing our photometry with JHK{sub s} data from the 2MASS catalog. These efforts allow us to define a robust sample of candidate main-sequence stars suitable for a purely empirical determination of the cluster's parameters by comparing them to the well-established Hyades main sequence. Our results confirm previous findings that NGC 3532 lies fairly near to the Sun [(m - M){sub 0} = 8.46 {+-} 0.05; 492{sup +12}{sub -11} pc] and has an extremely low reddening for its location near the Galactic plane [E(B - V) = 0.028 {+-} 0.006]. Moreover, an age of {approx}300 Myr has been derived for the cluster by fitting a set of overshooting isochrones to the well-populated upper main sequence. This new photometry also extends faint enough to reach the cluster white dwarf sequence, as confirmed by our photometric recovery of eight spectroscopically identified members of the cluster. Using the location of these eight members, along with the latest theoretical cooling tracks, we have identified {approx}30 additional white dwarf stars in the [V, (B - V)] CMD that have a high probability of belonging to NGC 3532. Reassuringly, the age we derive from fitting white dwarf isochrones to the locus of these stars, 300 {+-} 100 Myr, is consistent with the age derived from the turnoff. Our analysis of the photometry also includes an estimation of the binary star fraction as well as a determination of the cluster's luminosity and mass functions.

Clem, James L.; Landolt, Arlo U. [Department of Physics and Astronomy, Louisiana State University, Baton Rouge, LA 70803-4001 (United States); Hoard, D. W.; Wachter, Stefanie, E-mail: jclem@phys.lsu.edu, E-mail: landolt@phys.lsu.edu, E-mail: hoard@ipac.caltech.edu, E-mail: wachter@ipac.caltech.edu [Spitzer Science Center, California Institute of Technology, 1200 E. California Blvd., MC 220-6, Pasadena, CA 91125 (United States)

2011-04-15

372

Measuring Metallicities with Hubble Space Telescope/Wide-Field Camera 3 Photometry  

NASA Astrophysics Data System (ADS)

We quantified and calibrated the metallicity and temperature sensitivities of colors derived from nine Wide-Field Camera 3 filters on board the Hubble Space Telescope using Dartmouth isochrones and Kurucz atmosphere models. The theoretical isochrone colors were tested and calibrated against observations of five well studied galactic clusters, M92, NGC 6752, NGC 104, NGC 5927, and NGC 6791, all of which have spectroscopically determined metallicities spanning -2.30 < [Fe/H] <+0.4. We found empirical corrections to the Dartmouth isochrone grid for each of the following color-magnitude diagrams (CMDs): (F555W-F814W, F814W), (F336W-F555W, F814W), (F390M-F555W, F814W), and (F390W-F555W, F814W). Using empirical corrections, we tested the accuracy and spread of the photometric metallicities assigned from CMDs and color-color diagrams (which are necessary to break the age-metallicity degeneracy). Testing three color-color diagrams [(F336W-F555W),(F390M-F555W),(F390W-F555W), versus (F555W-F814W)], we found the colors (F390M-F555W) and (F390W-F555W) to be the best suited to measure photometric metallicities. The color (F390W-F555W) requires much less integration time, but generally produces wider metallicity distributions and, at very low metallicity, the metallicity distribution function (MDF) from (F390W-F555W) is ~60% wider than that from (F390M-F555W). Using the calibrated isochrones, we recovered the overall cluster metallicity to within ~0.1 dex in [Fe/H] when using CMDs (i.e., when the distance, reddening, and ages are approximately known). The measured MDF from color-color diagrams shows that this method measures metallicities of stellar clusters of unknown age and metallicity with an accuracy of ~0.2-0.5 dex using F336W-F555W, ~0.15-0.25 dex using F390M-F555W, and ~0.2-0.4 dex with F390W-F555W, with the larger uncertainty pertaining to the lowest metallicity range. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with program 11729 and 11664.

Ross, Teresa L.; Holtzman, Jon A.; Anthony-Twarog, Barbara J.; Bond, Howard E.; Twarog, Bruce; Saha, Abhijit; Walker, Alistair

2014-01-01

373

The WSRT wide-field HI survey: II. Local Group features  

E-print Network

We have used the WSRT to carry out an unbiased wide-field survey of HI emission features, achieving an RMS sensitivity of about 18 mJy/Beam at a velocity resolution of 17 km/s over 1800 deg^2. In this paper we present our HI detections at negative velocities which could be distinguished from the Galactic foreground. Fully 29% of the entire survey area has high velocity HI emission with N_HI exceeding our 3 sigma limit of about 1.5x10^17cm^-2 over 30 km/s. A faint population of discrete HVCs is detected in the immediate vicinity of M31 which spans a large fraction of the M31 rotation velocity. This class of features is confined to about 12 deg (160 kpc) projected radius of M31 and appears to be physically associated. We detect a diffuse northern extension of the Magellanic Stream (MS) from at least Dec=+20 to +40 deg., which then loops back toward the south. Recent numerical simulations had predicted just such an MS extension corresponding to the apo-galacticon portion of the LMC/SMC orbit at a distance of 125 kpc. A faint bridge of HI emission appears to join the systemic velocities of M31 with that of M33 and continues beyond M31 to the north-west. This may be the first detection of HI associated with the warm-hot intergalactic medium (WHIM). The distribution of peculiar velocity HI associated with M31 can be described by a projected exponential of 25 kpc scale-length and 5x10^17cm^-2 peak column density. We present the distribution function of N_HI in the extended M31 environment, which agrees well with the low red-shift QSO absorption line data over the range log(N_HI)=17.2 to 21.9. Our data extend this comparison about two orders of magnitude lower than previously possible and provide the first image of the Lyman limit absorption system associated with an L* galaxy. (abridged)

Robert Braun; David Thilker

2003-12-12

374

Bright z ~ 3 Lyman break galaxies in deep wide field surveys  

NASA Astrophysics Data System (ADS)

In my thesis I investigate the luminous z ˜ 3 Lyman break galaxies in deep wide field surveys. In the first part of the thesis, I use the LBT/LUCIFER to observe a lensed high-redshift star-forming galaxy (J0900+2234) at z = 2.03. With the high S/N near-IR spectroscopic observations, I reveal the detailed physical properties of this high-redshift galaxy, including SFR, metallicity, dust extinction, dynamical mass, and electron number density. In the second part of the thesis, I select a large sample of LBGs at z ˜ 3 from our new LBT Bootes field survey, and study the bright end luminosity function (LF), stellar mass function (SMF) and clustering properties of bright LBGs (1L* < L < 2.5L*). Together with other LF and SMF measurements, the evolution of LF and SMF can be well described by continuously rising star formation history model. Using the clustering measurements in this work and other works, a tight relation between the average host galaxy halo mass and the galaxy star formation rate is found, which can be interpreted as arising from cold flow accretion. The relation also suggests that the cosmic star formation efficiency is about 5%-20% of the total cold flow mass. This cosmic star formation efficiency does not evolve with redshift (from z ˜ 5 to z ˜ 3), hosting dark matter halo mass (1011 -- 1013 M? ), or galaxy luminosity (from 0.3L* to 3L* ). In the third and fourth parts, with the spectroscopic follow-up observations of the bright LBGs, I establish a sample of spectroscopically-confirmed ultraluminous LBGs (ULBGs) in NOAO Boo¨tes field. With this new ULBG sample, the rest-frame UV LF of LBG at M1700A = -23.0 was measured for the first time. I find that the ULBGs have larger outflow velocity, broader Lyalpha emission and ISM absorption line profiles, and more prominent C IV P-Cygni profile. This profile may imply a top-heavy IMF in these ULBGs. The ULBGs have larger stellar mass and SFR, but smaller dust extinction than the typical L* LBGs at z ˜ 2 -- 3. We proposed two evolutionary scenarios, pre-burst and post-burst. The properties of the ULBGs, especially the morphologies, prefer the pre-starburst scenario. Further high spatial resolution HST imaging and IFU spectroscopic observations will allow us to distinguish these two scenarios.

Bian, Fuyan

375

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

376

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

377

Predicting the number of giant arcs expected in the next-generation wide-field surveys from space  

NASA Astrophysics Data System (ADS)

In this paper, we estimate the number of gravitational arcs detectable in a wide-field survey such as that which will be operated by the Euclid space mission, assuming a ? cold dark matter cosmology. We use the publicly available code MOKA to obtain realistic deflection angle maps of mock gravitational lenses. The maps are processed by a ray-tracing code to estimate the strong lensing cross-sections of each lens. Our procedure involves (1) the generation of a light-cone which is populated with lenses drawn from a theoretical mass function, (2) the modelling of each single lens using a triaxial halo with a Navarro-Frenk-White density profile and theoretical concentration-mass relation, including substructures, (3) the determination of the lensing cross-section as a function of redshift for each lens in the light-cone and (4) the simulation of mock observations to characterize the redshift distribution of sources that will be detectable in the Euclid images. We focus on the so-called giant arcs, i.e. gravitational arcs characterized by large length-to-width ratios (l/w > 5, 7.5 and 10). We quantify the arc detectability at different significances above the level of the background. Performing 128 different realizations of a 15 000 deg2 survey, we find that the number of arcs detectable at 1? above the local background will be 8912-73+79, 2914-25+38 and 1275-15+22 for l/w ? 5, 7.5 and 10, respectively. The expected arc numbers decrease to 2409-28+24, 790-12+10 and 346-6+6 for a detection limit at 3? above the background level. From our analysis, we find that most of the lenses which contribute to the lensing optical depth are located at redshifts 0.4 < zl < 0.7 and that the 50 per cent of the arcs are images of sources at zs > 3. This is the first step towards the full characterization of the population of strong lenses that will be observed by Euclid. Given these results, we conclude that Euclid is a powerful instrument for strong lensing related science, which will be useful for several applications, ranging from arc and Einstein ring statistics to the measurement of the matter content in the cluster cores.

Boldrin, Michele; Giocoli, Carlo; Meneghetti, Massimo; Moscardini, Lauro

2012-12-01

378

Wide Field\\/Planetary Camera (WF\\/PC) contamination control assessment  

Microsoft Academic Search

The major concern of this study was the formation of a haze on the transmissive optics when exposed to a vacuum environment. The phenomena was determined to be a result of molecular transport from a low outgassing structural adhesive. Detailed analysis, both chemical and analytical, were conducted to assess the formation of the haze. Results of the study are given

C. Maag; J. Millard; M. Anderson

1988-01-01

379

Adaptive mesh optimization and nonrigid motion recovery based image registration for wide-field-of-view ultrasound imaging  

Microsoft Academic Search

Wide field of view (WFOV) imaging mode obtains an ultrasound image over an area much larger than the real time window normally available. As the probe is moved over the region of interest, new image frames are combined with prior frames to form a panorama image. Image registration techniques are used to recover the probe motion, eliminating the need for

Chaowei Tan; Bo Wang; Paul Liu; Dong Liu

2008-01-01

380

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

381

Wide Field/Planetary Camera (WF/PC) contamination control assessment  

NASA Astrophysics Data System (ADS)

The major concern of this study was the formation of a haze on the transmissive optics when exposed to a vacuum environment. The phenomena was determined to be a result of molecular transport from a low outgassing structural adhesive. Detailed analysis, both chemical and analytical, were conducted to assess the formation of the haze. Results of the study are given as well as information on clean-up and problem elimination.

Maag, C.; Millard, J.; Anderson, M.

382

Wide Field/Planetary Camera (WF/PC) contamination control assessment  

NASA Technical Reports Server (NTRS)

The major concern of this study was the formation of a haze on the transmissive optics when exposed to a vacuum environment. The phenomena was determined to be a result of molecular transport from a low outgassing structural adhesive. Detailed analysis, both chemical and analytical, were conducted to assess the formation of the haze. Results of the study are given as well as information on clean-up and problem elimination.

Maag, C.; Millard, J.; Anderson, M.

1988-01-01

383

The Dawn of Wide-Field Sunyaev-Zel'dovich Cluster Surveys: Efficient Optical Follow-Up  

E-print Network

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 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 2.7 Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 3 Stellar Locus

Weitz, David

384

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

385

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

386

A new low cost wide-field illumination method for photooxidation of intracellular fluorescent markers.  

PubMed

Analyzing cell morphology is crucial in the fields of cell biology and neuroscience. One of the main methods for evaluating cell morphology is by using intracellular fluorescent markers, including various commercially available dyes and genetically encoded fluorescent proteins. These markers can be used as free radical sources in photooxidation reactions, which in the presence of diaminobenzidine (DAB) forms an opaque and electron-dense precipitate that remains localized within the cellular and organelle membranes. This method confers many methodological advantages for the investigator, including absence of photo-bleaching, high visual contrast and the possibility of correlating optical imaging with electron microscopy. However, current photooxidation techniques require the continuous use of fluorescent or confocal microscopes, which wastes valuable mercury lamp lifetime and limits the conversion process to a few cells at a time. We developed a low cost optical apparatus for performing photooxidation reactions and propose a new procedure that solves these methodological restrictions. Our "photooxidizer" consists of a high power light emitting diode (LED) associated with a custom aluminum and acrylic case and a microchip-controlled current source. We demonstrate the efficacy of our method by converting intracellular DiI in samples of developing rat neocortex and post-mortem human retina. DiI crystals were inserted in the tissue and allowed to diffuse for 20 days. The samples were then processed with the new photooxidation technique and analyzed under optical microscopy. The results show that our protocols can unveil the fine morphology of neurons in detail. Cellular structures such as axons, dendrites and spine-like appendages were well defined. In addition to its low cost, simplicity and reliability, our method precludes the use of microscope lamps for photooxidation and allows the processing of many labeled cells simultaneously in relatively large tissue samples with high efficacy. PMID:23441199

da Silva Filho, Manoel; Santos, Daniel Valle Vasconcelos; Costa, Kauê Machado

2013-01-01

387

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

NASA Technical Reports Server (NTRS)

IRAC focal plane detector technology was developed and studies of alternate focal plane configurations were supported. While any of the alternate focal planes under consideration would have a major impact on the Infrared Array Camera, it was possible to proceed with detector development and optical analysis research based on the proposed design since, to a large degree, the studies undertaken are generic to any SIRTF imaging instrument. Development of the proposed instrument was also important in a situation in which none of the alternate configurations has received the approval of the Science Working Group.

Fazio, G. G.

1986-01-01

388

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

389

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

390

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

E-print Network

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

2014-01-01

391

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

392

Hubble Space Telescope Wide Field Planetary Camera 2 Observations of HH 1-2  

NASA Astrophysics Data System (ADS)

We present Hubble Space Telescope Wide Field Planetary Camera 2 images of the bipolar Herbig-Haro complex HH 1-2 in three emission lines (H?, [S ii], and [O iii]) and one continuum band (F702W). In addition to showing the complex morphology of these objects, the WFPC2 data allow us to resolve the cooling and recombination regions behind radiative shocks. This provides important diagnostics for the properties of the shocks present, including information about the direction of shock propagation and the postshock cooling length. The HH 1 jet can be interpreted as a series of bow shocks, consistent with models of the propagation of a pulsed jet. Evidence is seen both of the interaction of the jet with its surroundings and of internal shocks between knots. Large knot complexes are spaced with a period of around 15 yr, while internal structure within these complexes have characteristic separations corresponding to about 3.5 yr. Two knots at the base of the HH 1 jet point away from the main jet and do not line up with the outflow source at VLA 1. These may be associated with an outflow from a third source within the VLA 1/2 region. The HH 1 complex consists of multiple bow shocks that, at least in part, trace variations in jet direction with time. The misalignment between the direction of the visible HH 1 jet and the jet currently reaching the HH 1 bow shock are direct evidence of such variations. Arches on the west side of HH 1 are smooth, faint, display high excitation, and have well-resolved postshock cooling regions. Shoulders on the east side of HH 1 are bright, low excitation, and fragmented. This asymmetry is the result of a significant difference in the density and velocity of preshock material on either side of HH 1 and can be understood if the HH 1 jet is currently striking the edge of its own outflow cavity. The HH 1 knot F bow shock shows a gap in the [O iii] at its apex where the shock is fast enough to ionize beyond O^++ and the cooling time is long enough for material to flow out of the region before cooling. A nested double bow shock structure at this location may be the result of an incoming knot in a clumpy jet that is just overtaking its decelerated predecessor. Features located between VLA 1 and the HH 1 bow shock probably arise as a broader wind from VLA 1 encounters structure along the wall of the outflow cavity. HH 2 has an extremely complex structure, but on a feature-by-feature basis much of the physical structure of HH 2 can be understood, leading to a consistent overall description of the object. The HH 2 jet is currently encountering dense ambient gas. The working surface of the jet is seen as bright, high-ionization emission in the central region of the complex. This emission shows a clumpy appearance due largely to the short cooling lengths behind shocks driven into dense material. The larger bow shock accompanying the jet working surface can be traced as well. Flanking the working surface are several locations where a momentum-driven shell is fragmenting as a result of hydrodynamic and thermal instabilities that arise as it, too, runs into dense ambient material. The dense obstacle being encountered by HH 2 is localized. Fossil bow shocks and ``splatter'' from the jet can be observed moving around this obstacle on either side of HH 2, giving the object its ``indented'' appearance. As in HH 1, a broader wind accompanies the HH 2 jet. Interaction of this wind with ambient material is responsible for a number of features in HH 2, including the knot seen farthest from the outflow source. Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555.

Hester, J. Jeff; Stapelfeldt, Karl R.; Scowen, Paul A.

1998-07-01

393

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

394

Wide FastCam: a wide field imaging camera for the TCS  

NASA Astrophysics Data System (ADS)

The FastCam instrument, jointly developed by the IAC and the UPCT, allows, in real-time, acquisition, selection and storage of images with a resolution that reaches the diffraction limit of medium-sized telescopes. FastCam incorporates a specially designed software package to analyze series of tens of thousands of images in parallel with the data acquisition at the telescope. This instrument, well tested and used, has lead to another instrument with slightly different characteristics: Wide FastCam. Although it uses the same software for data acquisition, this time the objective does not look for lucky imaging but fast observations (some frames per second) in a much larger field of view. Wide FastCam consists of a 1k x 1k EMCCD detector and different optics offering a ~8 arcmin FOV. IDOM collaborated with IAC in the design of a high stability optical bench for the implementation of FastCam at the Telescopio Carlos Sánchez (TCS) and is currently collaborating in the implementation of Wide FastCam at the same telescope.

Murga, Gaizka; Oscoz, Alejandro; López, Roberto; Campo, Ramón; Etxegarai, Urtats; Pallé, Enric

2014-08-01

395

Computational intelligence in photonics technology and optical networks: A survey and future perspectives  

Microsoft Academic Search

The continuous growth of broadband communications, multimedia services and Internet is absolutely related to the deployment and operation of optical networks. Despite optical fibers’ enormous physical bandwidth the development of optical networks for today’s advanced, reliable and guaranteed-type services, require an efficient management of the bandwidth together with an orthological and careful use of optical components given their high manufacturing

Christos Riziotis; Athanasios V. Vasilakos

2007-01-01

396

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

E-print Network

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; Ma, Bin; Zhao, Cheng; Hu, Yi; Liu, Qiang

2014-01-01

397

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

398

Unique integration and test philosophy for the Wide-field Infrared Survey Explorer flight system  

NASA Astrophysics Data System (ADS)

The WISE observatory contains solid hydrogen to achieve cooling, which precludes many of the "test as you fly" (TAYF) methods for the integration and test of the WISE flight system due to the hazardous nature of the solid hydrogen. Additionally, there is reluctance to remove the optical cover after integration to the spacecraft due to increased risk. This paper discusses the WISE approach to verification and validation (V&V) given these constraints. As payloads increase in size and complexity more missions will necessarily deviate from the TAYF approach. The WISE system combines full testing of the instrument while the fight system uses an interment simulator for many of the flight system environmental tests. The test planning, simulator design, and the analyses which indicate why this would be a low-risk V&V approach for the WISE mission are discussed.

Howard, Joan F.; Shannon, Mark; Taylor, Nicholas; Liu, FengChuan; Abid, Mohamed; Heinrichsen, Ingolf

2008-07-01

399

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

400

A Wide-Field HI Study of the NGC 1566 Group  

E-print Network

We report on neutral hydrogen observations of a ~ 5.5 x 5.5 degree field around the NGC 1566 galaxy group with the multibeam narrow-band system on the 64-m Parkes telescope. We detected thirteen HI sources in the field, including two galaxies not previously known to be members of the group, bringing the total number of confirmed galaxies in this group to 26. Each of the HI galaxies can be associated with an optically catalogued galaxy. No 'intergalactic HI clouds' were found to an HI mass limit of ~ 3.5 x 10^8 Msun. We have estimated the expected HI content of the late-type galaxies in this group and find the total detected HI is consistent with our expectations. However, while no global HI deficiency is inferred for this group, two galaxies exhibit individual HI deficiencies. Further observations are needed to determine the gas removal mechanisms in these galaxies.

Virginia A. Kilborn; Baerbel S. Koribalski; Duncan A. Forbes; David G. Barnes; Ruth C. Musgrave

2004-09-30

401

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

402

Wide Field Planetary Camera 2 Observations of Leo A: A Predominantly Young Galaxy within the Local Group  

Microsoft Academic Search

The unprecedented detail of the Wide Field Planetary Camera 2 (WFPC2) color-magnitude diagrams (CMDs) of the resolved stellar population of Leo A presented here allows us to determine a new distance and an accurate star formation history for this extremely metal-poor Local Group dwarf irregular galaxy. From the position of the red clump, the helium-burning blue loops, and the tip

Eline Tolstoy; J. S. Gallagher; A. A. Cole; J. G. Hoessel; A. Saha; R. C. Dohm-Palmer; E. D. Skillman; Mario Mateo; D. Hurley-Keller

1998-01-01

403

I 5S: Wide-Field Light Microscopy with 100-nm-Scale Resolution in Three Dimensions  

Microsoft Academic Search

A new type of wide-field fluorescence microscopy is described, which produces 100-nm-scale spatial resolution in all three dimensions, by using structured illumination in a microscope that has two opposing objective lenses. Illumination light is split by a grating and a beam splitter into six mutually coherent beams, three of which enter the specimen through each objective lens. The resulting illumination

Lin Shao; Berith Isaac; Satoru Uzawa; David A. Agard; John W. Sedat; Mats G. L. Gustafsson

2008-01-01

404

The SuperWASP wide-field exoplanetary transit survey: candidates from fields 23 h < RA < 03 h  

Microsoft Academic Search

Photometric transit surveys promise to complement the currently known sample of extra-solar planets (ESPs) by providing additional information on the planets and especially their radii. Here, we present ESP candidates from one such survey called, the Wide Angle Search for Planets (WASP) obtained with the SuperWASP wide-field imaging system. Observations were taken with SuperWASP North located in La Palma during

D. J. Christian; D. L. Pollacco; I. Skillen; F. P. Keenan; W. I. Clarkson; A. Collier Cameron; S. R. Kane; T. A. Lister; R. G. West; B. Enoch; A. Evans; A. Fitzsimmons; C. A. Haswell; C. Hellier; S. T. Hodgkin; K. Horne; J. Irwin; A. J. Norton; J. Osborne; R. Ryans; P. J. Wheatley; D. M. Wilson

2006-01-01

405

Erratum: The Super WASP wide-field exoplanetary transit survey: candidates from fields 23 h < RA < 03 h  

Microsoft Academic Search

Photometric transit surveys promise to complement the currently known sample of extra-solar planets by providing additional information on the planets and especially their radii. Here we present extra-solar planet (ESP) candidates from one such survey called, the Wide Angle Search for Planets (WASP) obtained with the SuperWASP wide-field imaging system. Observations were taken with SuperWASP-North located in La Palma during

D. J. Christian; D. L. Pollacco; I. Skillen; F. P. Keenan; W. I. Clarkson; A. Collier Cameron; S. R. Kane; T. A. Lister; R. G. West; B. Enoch; A. Evans; A. Fitzsimmons; C. A. Haswell; C. Hellier; S. T. Hodgkin; K. Horne; J. Irwin; A. J. Norton; J. Osborne; R. Ryans; P. J. Wheatley; D. M. Wilson

2007-01-01

406

Confirmation of the Compactness of a z = 1.91 Quiescent Galaxy with Hubble Space Telescope's Wide Field Camera 3  

Microsoft Academic Search

We present very deep Wide Field Camera 3 (WFC3) photometry of a massive, compact galaxy located in the Hubble Ultra Deep Field. This quiescent galaxy has a spectroscopic redshift z = 1.91 and has been identified as an extremely compact galaxy by Daddi et al. We use new H F160W imaging data obtained with Hubble Space Telescope\\/WFC3 to measure the

Daniel Szomoru; Marijn Franx; Pieter G. van Dokkum; Michele Trenti; Garth D. Illingworth; Ivo Labbé; Rychard J. Bouwens; Pascal A. Oesch; C. Marcella Carollo

2010-01-01

407

Power cable fault management with fiber optic distributed sensors: future technological trends  

NASA Astrophysics Data System (ADS)

This paper presents an analysis of fiber distributed sensors applied to power cable fault management, and proposes a more suitable solution for the future. In tomorrow's fast-paced deregulated environment, exploiting new technologies for competitive advantage has become a major incentive in the power business delivery. In power lines, the main parameters that need real time checking are temperature, partial discharges, and mechanical forces. If unchecked, these parameters can seriously damage the insulation system of high-voltage power apparatus and them reduce their life expectancy. This paper deals with these three parameters and presents today's state-of-the-art. The first part analyzes the current situation by pointing out the most commonly used technique for temperature measureme