FOS Closeout Calibration: Sensitivity Reference File Update and Delivery (30-Jan-1998)

An updated set of AIS sensitivity reference files and tables has been delivered. The new calibration derives from the FOS Closeout Calibration analysis.

• POST-COSTAR: The new files incorporate the results of standard star observations taken over the entire post-COSTAR period (as opposed to the 1994-95 period covered in the previous calibration set). Additionally, all standard star observations have been flatfield corrected with the FOS Closeout Flatfields appropriate to each individual observing epoch. Time-dependent sensitivity changes continue to be tracked for FOS/RD G190H and G160L only. Aperture-throughputs for 0.1-PAIR and the barred apertures have now been incorporated so that these apertures can be flux-calibrated by normal running of CALFOS.
• PRE-COSTAR: As for the post-COSTAR case, aperture-throughputs for 0.1-PAIR and the barred apertures have been incorporated so that these apertures can be flux-calibrated by normal running of CALFOS. No changes to the pre-COSTAR sensitivities have been introduced, however.

The FOS chapters in Volume II of the third edition of the HST Data Handbook provide a complete discussion of the limitations of FOS flux calibration with these reference files. A full description of the new calibration will be presented in forthcoming FOS ISR CAL/FOS-157.

The accompanying table lists the best set of FOS sensitivity files and tables. All of these files are available through StarView or via anonymous ftp from

ftp.stsci.edu/cdbs/cdbs2/yref

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30 January 1998

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