17.7	Cycle 10 Calibration

The STIS Cycle 10 calibration plan was in turn very similar to the Cycle 9 calibration program. Supported modes continued to be monitored for items such as sensitivity changes, flat-field evolution, dispersion solutions, and evolution of charge transfer efficiency of the CCD detector.

In addition to monitoring instrument health and safety and maintaining the overall calibration of STIS supported modes at the accuracies as established during Cycles 7 through 9, a few new calibration programs were added for Cycle 10, with the following goals.

1:	To obtain exposures of primary spectrophotometric standard stars in every single supported spectroscopic mode of STIS, including the echelle and first-order medium-resolution modes;

2:	To characterize the effect of the presence of bright stars outside the field of view of the STIS CCD on the amount of scattered light;

3:	To further improve PSF characterization for the CCD in imaging and coronagraphic mode as a function of source color;

4:	To finalize the accurate determination of the throughput curve of the Long-Pass filter used for CCD imaging;

5:	To monitor the throughput curves of the broad-band and medium-band imaging filters used with the MAMA’s and the CCD;

6:

To characterize STIS spectroscopic performance at the recently defined, “pseudo-apertures” located near row 900 of the CCD (see Section 7.3.8) that have been defined to ameliorate losses due to the decreasing charge transfer efficiency of the CCD with time. Spectroscopic sensitivity, PSFs, and LSFs will be measured at the pseudo-apertures using all supported long slits.

The results of all the Cycle 9 calibration programs are presented in the close-out report STIS ISR 2004-06.