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NIRCAM image simulations for NGST wavefront sensing

Sivaramakrishnan, Anand and Makidon, Russell B. and Figer, Donald F. and Jedrzejewski, Robert I. and Bushouse, Howard A. and Krist, John E. and Stockman, H. S. and Hodge, Philip E. and Dencheva, Nadezhda M. and Rauscher, Bernard J. and Laidler, Victoria G. and Ohara, Catherine and Redding, David C. and Im, Myungshin and Offenberg, Joel D. (2003) NIRCAM image simulations for NGST wavefront sensing. In: IR Space Telescopes and Instruments. Proceedings of SPIE. No.4850. Society of Photo-optical Instrumentation Engineers (SPIE) , Bellingham, WA, pp. 388-397. ISBN 9780819446299.

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The Next Generation Space Telescope (NGST) will be a segmented, deployable, infrared-optimized 6.5m space telescope. Its active primary segments will be aligned, co-phased, and then fine-tuned in order to deliver image quality sufficient for the telescope's intended scientific goals. Wavefront sensing used to drive this tuning will come from the analysis of focussed and defocussed images taken with its near-IR science camera, NIRCAM. There is a pressing need to verify that this will be possible with the near-IR detectors that are still under development for NGST. We create simulated NIRCAM images to test the maintenance phase of this plan. Our simulations incorporate Poisson and electronics read noise, and are designed to be able to include various detector and electronics non-linearities. We present our first such simulation, using known or predicted properties of HAWAII HgCdTe focal plane array detectors. Detector effects characterized by the Independent Detector Testing Laboratory will be included as they become available. Simulating InSb detectors can also be done within this framework in future. We generate Point-Spread Functions (PSF's) for a segmented aperture geometry with various wavefront aberrations, and convolve this with typical galaxy backgrounds and stellar foregrounds. We then simulate up-the-ramp (MULTIACCUM in HST parlance) exposures with cosmic ray hits. We pass these images through the HST NICMOS `CALNICA' calibration task to filter out cosmic ray hits. The final images are to be fed to wavefront sensing software, in order to find the ranges of exposure times, filter bandpass, defocus, and calibration star magnitude required to keep the NGST image within its specifications.

Item Type:Book Section
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URLURL TypeDescription
Bushouse, Howard A.0000-0001-6664-7585
Im, Myungshin0000-0002-8537-6714
Additional Information:© 2003 Society of Photo-optical Instrumentation Engineers (SPIE). We acknowledge useful discussions with Eddie Bergeron, Perry Greenfield, Todd Miller, Megan Sosey, and Rick White.
Group:Infrared Processing and Analysis Center (IPAC)
Subject Keywords:NGST wavefront sensing and control, FPA detector simulation, cosmic ray removal, intra-pixel sensitivity
Series Name:Proceedings of SPIE
Issue or Number:4850
Record Number:CaltechAUTHORS:20190116-095426520
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Official Citation:Anand Sivaramakrishnan, Russell B. Makidon, Donald Frank Figer, Robert Ian Jedrzejewski, Howard A. Bushouse, John E. Krist, H.S. Peter Stockman, Philip Hodge, Nadezhda M. Dencheva, Bernard J. Rauscher, Victoria G. Laidler, Catherine Mayumi Ohara, David C. Redding, Myungshin Im, Joel D. Offenberg, "NIRCAM image simulations for NGST wavefront sensing," Proc. SPIE 4850, IR Space Telescopes and Instruments, (5 March 2003); doi: 10.1117/12.461933
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:92313
Deposited By: Tony Diaz
Deposited On:18 Jan 2019 03:52
Last Modified:16 Nov 2021 03:49

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