... Cycle 23 STIS Instrument Handbook . ... Space Telescope Imaging Spectrograph Instrument Handbook for Cycle 23 > Chapter 2: Special Considerationsfor Cycle 23 > 2.2 Summary of STIS Performance Changes Since 2004 . 2.2 . Summary of STIS Performance Changes Since 2004 . While in most respects the performance of STIS after its repair during SM4 is similar to its performance prior to the 2004 failure, there are some important differences. ... Changes in CCD Read Noise? CCD Dark Current? ...