Mr. Samuel L. Crawford Profile

Samuel L. Crawford

Senior Engineer at Jet Propulsion Lab

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Author

Publications (18)

Proceedings Article | 26 September 2013 Paper

Starshade optical edge modeling, requirements, and laboratory tests

Stefan Martin, Stuart Shaklan, Samuel Crawford, Siu-Chun Lee, Behrouz Khayatian, Daniel Hoppe, Eric Cady, P. Douglas Lisman

Proceedings Volume 8864, 88641A (2013) https://doi.org/10.1117/12.2024188

KEYWORDS: Telescopes, Sun, Space telescopes, Exoplanets, Diffraction, Stars, Scattering, Reflector telescopes, Sensors, Polarization

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Proceedings Article | 26 September 2013 Paper

Precision near-infrared radial velocity instrumentation II: noncircular core fiber scrambler

Peter Plavchan, M. Bottom, P. Gao, J. Wallace, B. Mennesson, D. Ciardi, S. Crawford, S. Lin, C. Beichman, C. Brinkworth, J. Johnson, C. Davison, R. White, G. Anglada-Escude, K. von Braun, G. Vasisht, L. Prato, S. Kane, A. Tanner, B. Walp, S. Mills

Proceedings Volume 8864, 88640G (2013) https://doi.org/10.1117/12.2023696

KEYWORDS: Mirrors, Spectrographs, Calibration, Cameras, Telescopes, Stars, Visible radiation, Velocity measurements, Planets, K band

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We have built and commissioned a prototype agitated non-circular core ber scrambler for precision spectroscopic radial velocity measurements in the near-infrared H band. We have collected the rst on-sky performance and modal noise tests of these novel bers in the near-infrared at H and K bands using the CSHELL spectrograph at the NASA InfraRed Telescope Facility (IRTF). We discuss the design behind our novel reverse injection of a red laser for co-alignment of star-light with the ber tip via a corneWe have built and commissioned a prototype agitated non-circular core fiber scrambler for precision spectroscopic radial velocity measurements in the near-infrared H band. We have collected the first on-sky performance and modal noise tests of these novel fibers in the near-infrared at H and K bands using the CSHELL spectrograph at the NASA InfraRed Telescope Facility (IRTF). We discuss the design behind our novel reverse injection of a red laser for co-alignment of star-light with the fiber tip via a corner cube and visible camera. We summarize the practical details involved in the construction of the fiber scrambler, and the mechanical agitation of the fiber at the telescope. We present radial velocity measurements of a bright standard star taken with and without the fiber scrambler to quantify the relative improvement in the obtainable blaze function stability, the line spread function stability, and the resulting radial velocity precision. We assess the feasibility of applying this illumination stabilization technique to the next generation of near-infrared spectrographs such as iSHELL on IRTF and an upgraded NIRSPEC at Keck. Our results may also be applied in the visible for smaller core diameter fibers where Fiber modal noise is a significant factor, such as behind an adaptive optics system or on a small < 1 meter class telescope such as is being pursued by the MINERVA and LCOGT collaborations.r cube and visible camera. We summarize the practical details involved in the construction of the ber scrambler, and the mechanical agitation of the ber at the telescope. We present radial velocity measurements of a bright standard star taken with and without the ber scrambler to quantify the relative improvement in the obtainable blaze function stability, the line spread function stability, and the resulting radial velocity precision. We assess the feasibility of applying this illumination stabilization technique to the next generation of near-infrared spectrographs such as iSHELL on IRTF and an upgraded NIRSPEC at Keck. Our results may also be applied in the visible for smaller core diameter bers where ber modal noise is a signi cant factor, such as behind an adaptive optics system or on a small < 1 meter class telescope such as is being pursued by the MINERVA and LCOGT collaborations.

Proceedings Article | 26 September 2013 Paper

Precision near-infrared radial velocity instrumentation I: absorption gas cells

Peter Plavchan, G. Anglada-Escude, R. White, P. Gao, C. Davison, S. Mills, C. Beichman, C. Brinkworth, J. Johnson, M. Bottom, D. Ciardi, K. Wallace, B. Mennesson, K. von Braun, G. Vasisht, L. Prato, S. Kane, A. Tanner, B. Walp, S. Crawford, S. Lin

Proceedings Volume 8864, 88641J (2013) https://doi.org/10.1117/12.2023690

KEYWORDS: Data modeling, Methane, Calibration, Absorption, Spectrographs, Stars, Planets, Exoplanets, Velocity measurements, Satellites

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Proceedings Article | 13 September 2012 Paper

A phase-shifting Zernike wavefront sensor for the Palomar P3K adaptive optics system

J. Kent Wallace, Sam Crawford, Frank Loya, James Moore

Proceedings Volume 8447, 84472K (2012) https://doi.org/10.1117/12.927041

KEYWORDS: Wavefront sensors, Adaptive optics, Cameras, Phase shifts, Mirrors, Telescopes, Capillaries, Space telescopes, Wavefronts, Reflectivity

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Proceedings Article | 28 July 2008 Paper

Keck Interferometer nuller update

M. M. Colavita, E. Serabyn, A. J. Booth, S. L. Crawford, J. I. Garcia-Gathright, E. R. Ligon, B. L. Mennesson, C. G. Paine, P. L. Wizinowich, S. Ragland, E. C. Appleby, B. C. Berkey, A. Cooper, W. Dahl, J. T. Gathright, M. A. Hrynevych, D. W. Medeiros, D. Morrison, T. Panteleeva, B. Smith, K. R. Summers, K. Tsubota, C. Tyau, E. Wetherell, J. M. Woillez, R. L. Akeson, R. Millan-Gabet, C. Felizardo, C. D. Koresko, J. S. Herstein

Proceedings Volume 7013, 70130A (2008) https://doi.org/10.1117/12.789476

KEYWORDS: Nulling interferometry, Signal to noise ratio, Interferometers, Cameras, Calibration, Stars, Telescopes, Phase shift keying, K band, Modulation

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Proceedings Article | 28 July 2008 Paper

Recent progress at the Keck Interferometer: operations and V2 science

S. Ragland, P. Wizinowich, R. Akeson, M. Colavita, E. Appleby, B. Berkey, A. Booth, A. Cooper, S. Crawford, W. Dahl, C. Felizardo, J. Garcia-Gathright, J. Herstein, M. Hrynevych, C. Koresko, R. Ligon, D. Medeiros, B. Mennesson, R. Millan-Gabet, D. Morrison, C. Paine, B. Parvin, T. Panteleeva, E. Serabyn, B. Smith, K. Summers, K. Tsubota, C. Tyau, E. Wetherell, J. Woillez

Proceedings Volume 7013, 70130B (2008) https://doi.org/10.1117/12.788070

KEYWORDS: Nulling interferometry, Stars, Cameras, Telescopes, Interferometers, Adaptive optics, Visibility, Mirrors, L band, Cryogenics

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Proceedings Article | 28 June 2006 Paper

Science observations with the Keck Interferometer Nuller

E. Serabyn, A. Booth, M. Colavita, S. Crawford, J. Garcia, J. Gathright, M. Hrynevych, C. Koresko, R. Ligon, B. Mennesson, T. Panteleeva, S. Ragland, K. Summers, W. Traub, K. Tsubota, E. Wetherell, P. Wizinowich, J. Woillez

Proceedings Volume 6268, 626815 (2006) https://doi.org/10.1117/12.672621

KEYWORDS: Nulling interferometry, Stars, Interferometers, Visibility, Remote sensing, Adaptive optics, Cameras, Keck Observatory, K band, Data modeling

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Proceedings Article | 28 June 2006 Paper

Design and performance of the Keck angle tracker

S. Crawford, S. Ragland, A. Booth, M. Colavita, E. Hovland

Proceedings Volume 6268, 62683W (2006) https://doi.org/10.1117/12.672063

KEYWORDS: Mirrors, Telescopes, Interferometers, Staring arrays, Wavefronts, Adaptive optics, Stars, Prisms, Keck Observatory, Nulling interferometry

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Proceedings Article | 15 September 2005 Paper

Final laboratory integration and test of the Keck Interferometer nuller

S. Crawford, M. Colavita, J. Garcia, E. Ligon, B. Mennesson, C. Paine, E. Serabyn, R. Smythe, M. Swain, G. Vasisht

Proceedings Volume 5905, 59050U (2005) https://doi.org/10.1117/12.619131

KEYWORDS: Nulling interferometry, Interferometers, Mid-IR, Cameras, Beam splitters, Sensors, Stars, Exoplanets, Planets, Colorimetry

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Proceedings Article | 15 September 2005 Paper

The Keck interferometer nuller (KIN): configuration, measurement approach, and first results

E. Serabyn, E. Appleby, J. Bell, A. Booth, J. Chin, M. Colavita, S. Crawford, M. Creech-Eakman, W. Dahl, J. Fanson, J. Garcia, J. Gathright, E. Hovland, M. Hrynevych, C. Koresko, R. Ligon, B. Mennesson, J. Moore, D. Palmer, T. Panteleeva, C. Paine, S. Ragland, L. Reder, T. Saloga, R. Smythe, C. Tyau, K. Tsubota, G. Vasisht, E. Wetherell, P. Wizinowich, J. Woillez

Proceedings Volume 5905, 59050T (2005) https://doi.org/10.1117/12.618228

KEYWORDS: Nulling interferometry, Metrology, Beam splitters, Near infrared, Cameras, Stars, Mirrors, Interferometers, K band, Keck Observatory

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Proceedings Article | 20 October 2004 Paper

The Keck interferometer nuller: system architecture and laboratory performance

Eugene Serabyn, Andrew Booth, M. Colavita, Michelle Creech-Eakman, Samuel Crawford, Jean Garcia, Richard Johnson, Erik Hovland, C. Koresko, Edgar Ligon, Stefan Martin, Bertrand Mennesson, James Moore, Dean Palmer, Christopher Paine, Michael Shao, Mark Swain, Robert Smythe, Gautam Vasisht

Proceedings Volume 5491, (2004) https://doi.org/10.1117/12.552195

KEYWORDS: Nulling interferometry, Beam splitters, Metrology, Interferometers, Cameras, Stars, Mid-IR, Keck Observatory, Interferometry, Signal detection

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Proceedings Article | 19 November 2003 Paper

Mid-infrared nuller for Terrestrial Planet Finder: design, progress, and results

Stefan Martin, Robert Gappinger, Frank Loya, Bertrand Mennesson, Samuel Crawford, Eugene Serabyn

Proceedings Volume 5170, (2003) https://doi.org/10.1117/12.521312

KEYWORDS: Nulling interferometry, Mirrors, Beam splitters, Sensors, Control systems, Gas lasers, Planets, Polarization, Carbon monoxide, Stars

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Proceedings Article | 21 February 2003 Paper

Tabletop mid-infrared nulling testbed for the Keck interferometer and the Terrestrial Planet Finder

Christopher Koresko, Bertrand Mennesson, Samuel Crawford, Michelle Creech-Eakman, J. Kent Wallace, Eugene Serabyn

Proceedings Volume 4838, (2003) https://doi.org/10.1117/12.458017

KEYWORDS: Nulling interferometry, Sensors, Signal detection, Beam splitters, Interferometers, Mid-IR, Mirrors, Thermography, Light sources, Modulation

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Proceedings Article | 11 September 1998 Paper

UnISIS: a laser-guided adaptive optics system for the Mt. Wilson 2.5-m telescope

Laird Thompson, Richard Castle, Scott Teare, Peter McCullough, Samuel Crawford

Proceedings Volume 3353, (1998) https://doi.org/10.1117/12.321707

KEYWORDS: Laser guide stars, Sensors, Wavefronts, Adaptive optics, Mirrors, Telescopes, Stars, Deformable mirrors, Cameras, Laser optics

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Proceedings Article | 24 July 1998 Paper

Aperture synthesis imaging with the Keck Interferometer

Gautam Vasisht, Andrew Boden, M. Mark Colavita, Samuel Crawford, Michael Shao, Paul Swanson, Gerard van Belle, J. Kent Wallace, James Walker, Peter Wizinowich

Proceedings Volume 3350, (1998) https://doi.org/10.1117/12.317097

KEYWORDS: Interferometers, Telescopes, Stars, Sensors, Adaptive optics, Synthetic apertures, Astronomy, Interferometry, Atmospheric optics, Spatial resolution

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Proceedings Article | 24 July 1998 Paper

Keck Interferometer

M. Mark Colavita, Andrew Boden, Samuel Crawford, Aden Meinel, Michael Shao, Paul Swanson, Gerard van Belle, Gautam Vasisht, James Walker, J. Kent Wallace, Peter Wizinowich

Proceedings Volume 3350, (1998) https://doi.org/10.1117/12.317145

KEYWORDS: Stars, Interferometers, Telescopes, Planets, Mirrors, Nulling interferometry, Space telescopes, Sensors, Adaptive optics, Infrared radiation

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Proceedings Article | 26 June 1995 Paper

System-wide design issues for the stellar interferometer technology experiment (SITE)

David Miller, Samuel Crawford, T. Tupper Hyde, Brett Masters, Edward Crawley, Gary Blackwood, M. Mark Colavita, Jeffrey Yu, Michael Shao, Robert Laskin

Proceedings Volume 2477, (1995) https://doi.org/10.1117/12.212998

KEYWORDS: Interferometers, Sensors, Stars, Wavefronts, Space operations, Optical benches, Control systems, Aerospace engineering, Visibility, Spatial resolution

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Proceedings Article | 13 September 1994 Paper

Stellar interferometer tracking experiment (SITE): a precursor mission for multiple-aperture interferometry in space

Samuel Crawford, David Miller, Michael Shao

Proceedings Volume 2209, (1994) https://doi.org/10.1117/12.185264

KEYWORDS: Interferometers, Sensors, Mirrors, Beam splitters, Spatial resolution, Visibility, Photons, Space telescopes, UV optics, Computer aided design

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Showing 5 of 18 publications

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