Version 5.1 of this Handbook includes an update of STIS operations in Chapter 2 and minor, but significant changes to the discussion of sky backgrounds and the Exposure Time Calculator in Chapter 6. In particular, the ETC will now assume low, average, and high backgrounds corresponding to apparent V-band magnitudes per square arcsec of 23.3, 22.7, and 22.1, respectively, and better representing the actual ranges commonly encountered. The associated discussion of zodiacal and Earthshine contributions to the background have been modified for consistency.
|
Space Telescope Science Institute http://www.stsci.edu Voice: (410) 338-1082 help@stsci.edu |