|STIS Instrument Handbook for Cycle 25|
17.7 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;
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.