Determine the stability of the spectrograph portion of STIS, for the CCD modes. This program samples the variations in each mode during changes in the thermal environment of the telescope. Each spectroscopic mode is sampled over time periods of 1 orbit on 5 separate occasions. If the variations with temperature are significantly different for the two modes studies, then a request will be made to monitor other CCD modes. This test will show the required frequency of readouts.
Goals are dependent on any additional wave- length accuracy needed by the observer.