Calibration of HST WF/PC for quantitative analysis of faint images

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Session 113 -- HST, UIT and UV Instruments, UV Processing and Archives
Display presentation, Saturday, January 15, 9:30-6:45, Salons I/II Room (Crystal Gateway)

[113.04] Calibration of HST WF/PC for quantitative analysis of faint images

E. W. Wyckoff, K. U. Ratnatunga, R. E. Griffiths, S. Casertano, L. W. Neuschaefer (Johns Hopkins University)

We discuss the procedures adopted to optimize the calibration of the Hubble Space Telescope Wide Field Camera and to improve quantitative measurement of faint images. We use exposures of random sky fields that were taken in parallel mode when another detector was being used on a primary target extending two or more orbits. The observations are part of the Medium-Deep Survey, which will generate an object catalog that is useful for statistical studies in both Galactic and extra-galactic astronomy. We present improved flatfields for use with the F555W and F785LP filters. The flatfields constructed by creating a skyflat from all suitable WFC data taken between August 1992 and July 1993 allow for a single zero-point for all 4-CCDs and achieve a rms error of order 2\%.

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