This report describes an effort to obtain calibration information for the digital data from the geosynchronous satellite visual sensors. The visual sensor calibration differs for each satellite, and sensitivity may decay over period of several years. In addition, changes in the NOAA-NESS sensor compatibility table at times affect overall sensor calibration. Tables of calibration factors are presented for GOES-1 and GOES-2, and SMS-1 and SMS-2, for March 1978 through August 1980. Simple, constant calibrations are adequate for less demanding applications such as distinguishing clouds from land or water. Where more precision is necessary, such as identifying haze, one must allow for variations in calibration factors, as presented in the tables.