ST-ECF Instrument Science Report

POA/FOS - 2001 - 03
POA Analysis of FOS Flat Fields

P. Bristow, A. Alexov, F. Kerber & M. R. Rosa
December 2001

Abstract
The derivation and use of flats fields in the calibration pipeline was,
from the start, identified as an area for the POA project to examine.
The original motivation was the possibility that a more physical model
could be applied to decouple the contributions from the photocathode and
the diode array respectively. However, it was found that the implications
of the GIMP and Y-base corrections made the re-derivation of the flats
essential regardless of other considerations. This report discusses first
the investigation of possible areas of improvement and then gives details
of the modifications made to the FOS blue side flat fields as used by the
poa_calfos pipeline.

Key words:  Data Reduction, Calibration, Space Telescope. Faint Object
Spectrograph, Flat Fields, Data Archive