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Proceedings Paper

The COS calibration pipeline and verification process
Author(s): Mary Elizabeth Kaiser; Philip E. Hodge; Charles Keyes; David Sahnow; Thomas Ake; Alessandra Aloisi; Stephane Béland; Rosa Diaz; Scott Friedman; Cynthia Froning; Parviz Ghavamian; James Green; Jason McPhate; Cristina Oliveira; Steve Osterman; Steve Penton; Brittany Shaw; Erik Wilkinson
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Paper Abstract

The Cosmic Origins Spectrograph,1 COS, will be installed in the Hubble Space Telescope (HST) during the next servicing mission. This will be the most sensitive ultraviolet spectrograph ever flown aboard the HST. The calibration pipeline (CALCOS), written in Python, has been developed by the Space Telescope Science Institute (STScI) to support the calibration of HST/COS data. As with other HST pipelines, CALCOS uses an association table to specify the data files to be included, and employs header keywords to specify the calibration steps to be performed and the reference files to be used. CALCOS is designed with a common underlying structure for processing far ultraviolet (FUV) and near ultraviolet (NUV) channels which, respectively, use a cross delay line and a Multi Anode Microchannel Array (MAMA) detector. The pipeline basics and channel dependent specifics are presented. The generation and application of the current reference files, derived from ground-based calibration data, is described, along with the pipeline verification process and results. The CALCOS calibration includes pulse-height filtering and geometric correction for the FUV channel; flat-field, deadtime, and Doppler correction for both channels. Methods for obtaining an accurate wavelength calibra-tion using the on-board spectral line lamp are described. The instrument sensitivity is applied to the background corrected spectrum to produce the final flux calibrated spectrum.

Paper Details

Date Published: 23 July 2008
PDF: 13 pages
Proc. SPIE 7014, Ground-based and Airborne Instrumentation for Astronomy II, 70146G (23 July 2008); doi: 10.1117/12.790239
Show Author Affiliations
Mary Elizabeth Kaiser, Space Telescope Science Institute (United States)
Johns Hopkins Univ. (United States)
Philip E. Hodge, Space Telescope Science Institute (United States)
Charles Keyes, Space Telescope Science Institute (United States)
David Sahnow, Space Telescope Science Institute (United States)
Johns Hopkins Univ. (United States)
Thomas Ake, Space Telescope Science Institute (United States)
Alessandra Aloisi, Space Telescope Science Institute (United States)
Stephane Béland, Ctr. for Astrophysics and Space Astronomy, Univ. of Colorado, Boulder (United States)
Rosa Diaz, Space Telescope Science Institute (United States)
Scott Friedman, Space Telescope Science Institute (United States)
Cynthia Froning, Ctr. for Astrophysics and Space Astronomy, Univ. of Colorado, Boulder (United States)
Parviz Ghavamian, Space Telescope Science Institute (United States)
James Green, Ctr. for Astrophysics and Space Astronomy, Univ. of Colorado, Boulder (United States)
Jason McPhate, Space Sciences Lab.,Univ. of California, Berkeley (United States)
Cristina Oliveira, Space Telescope Science Institute (United States)
Johns Hopkins Univ. (United States)
Steve Osterman, Ctr. for Astrophysics and Space Astronomy, Univ. of Colorado, Boulder (United States)
Steve Penton, Ctr. for Astrophysics and Space Astronomy, Univ. of Colorado, Boulder (United States)
Brittany Shaw, Space Telescope Science Institute (United States)
Erik Wilkinson, Ball Aerospace and Technologies Corp. (United States)


Published in SPIE Proceedings Vol. 7014:
Ground-based and Airborne Instrumentation for Astronomy II
Ian S. McLean; Mark M. Casali, Editor(s)

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