NIRCAM image simulations for NGST wavefront sensing

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

doi:10.1117/12.461933

5 March 2003 NIRCAM image simulations for NGST wavefront sensing

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

Author Affiliations +

Proceedings Volume 4850, IR Space Telescopes and Instruments; (2003) https://doi.org/10.1117/12.461933
Event: Astronomical Telescopes and Instrumentation, 2002, Waikoloa, Hawai'i, United States

Abstract

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.

Citation Download 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, and Joel D. Offenberg "NIRCAM image simulations for NGST wavefront sensing", Proc. SPIE 4850, IR Space Telescopes and Instruments, (5 March 2003); https://doi.org/10.1117/12.461933

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available