Instrument Science Report STIS 97-07Pre-Launch NUV MAMA Flats

A full set of flat field calibration files for the NUV MAMA has been generated from pre-flight laboratory data. An iterative technique with 12 passes through each raw flat data image is used to separate the illuminating lamp signature from the high frequency struc-ture of the MAMA flat itself. The set of flats consists of one wavelength independent P-flat that corrects for the high frequency pixel-to-pixel sensitivity variations and 63 L-flats that correct for the lower frequency, wavelength dependent variations. The S/N of the counting statistics of the P-flat is over 300 per MAMA resolution element (2x2 lores pixels.) On-orbit tests are required to confirm the validity of the ground based flats for the reduction of flight data. 1