AAS 200th meeting, Albuquerque, NM, June 2002
Session 62. HST Instrumentation
Display, Wednesday, June 5, 2002, 10:00am-7:00pm, SW Exhibit Hall

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[62.10] Improvements to STIS Pipeline Calibration

R.I. Diaz-Miller, J. Kim-Quijano, J. Valenti, C.R. Proffitt (Space Telescope Science Institute), D. Lindler (Advanced Computer Concepts, Inc.)

In the last few months a number of improvements to the STIS pipeline calibration have been developed and implemented.

We have released new low order flat files for use with G140L observations. These flats should reduce variations of the extracted flux with position from 12% to 2%.

To better reflect the change with time in the overall shape of the NUV MAMA dark current, new dark reference files were created for different epochs. Furthermore, since the true NUV dark current at any given time is a complicated function of the recent temperature history of the detector, an improved algorithm for scaling the NUV darks has also been implemented in the pipeline. Combining the revised scaling formula and the new dark files can result in significant improvements in the dark subtraction, and can largely eliminate the bright edges that often appear in dark limited NUV observations.

Each month, echelle spectra are offset slightly to prevent localized overuse of the MAMA detectors. This offset shifts the wavelength scale and the echelle blaze function by different amounts. Pipeline enhancements will account for this effect, improving agreement where orders overlap.


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Bulletin of the American Astronomical Society, 34
© 2002. The American Astronomical Soceity.