Refinement of the Spitzer Space Telescope Pointing History Based on Image Registration Corrections from Multiple Data Channels
Abstract
Position reconstruction for images acquired by the Infrared Array Camera (IRAC), one of the science instruments onboard the Spitzer Space Telescope, is a multistep procedure that is part of the routine processing done at the Spitzer Science Center (SSC). The IRAC instrument simultaneously images two different sky footprints, each with two independent infrared passbands (channels). The accuracy of the initial Spitzer pointing reconstruction is typically slightly better than 1". The well‐known technique of position matching imaged point sources to even more accurate star catalogs to refine the pointing further is implemented for SSC processing of IRAC data as well. Beyond that, the optimal processing of redundant pointing information from multiple instrument channels to yield an even better solution is also performed at the SSC. Our multichannel data processing approach is particularly beneficial when the star‐catalog matches are sparse in one channel but copious in others. A thorough review of the algorithm as implemented for the Spitzer mission reveals that the mathematical formalism can be fairly easily generalized for application to other astronomy missions. The computation of pointing uncertainties, the interpolation of pointing corrections and their uncertainties between measurements, and the estimation of random‐walk deviations from linearity are special areas of importance when implementing the method. After performing the operations described in this paper on the initial Spitzer pointing, the uncertainty in the observatory pointing history file is reduced 10–15 fold.
Additional Information
© 2007 The Astronomical Society of the Pacific. Received 2007 June 27; accepted 2007 September 12; published 2007 December 3. This work is based in part on archival data obtained with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA. Support for this work was provided by an award issued by JPL/Caltech.Attached Files
Published - MCCpasp07.pdf
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Additional details
- Eprint ID
- 17449
- Resolver ID
- CaltechAUTHORS:20100211-082830369
- NASA/JPL/Caltech
- Created
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2010-02-12Created from EPrint's datestamp field
- Updated
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2021-11-08Created from EPrint's last_modified field
- Caltech groups
- Infrared Processing and Analysis Center (IPAC)