Abstract

On Friday 11th October 1991, after one month of outgassing, SUSIM commenced observing the sun near the maximum of activity in cycle 22. Since then, scans of spectral irradiance from 115 to 410 nm have been collected dally with 1 nm and 5 nm resolution, and weekly with 0.15 nm resolution. During the first week of solar observing, SUSIM’s responsivity was calibrated by each of four on-board deuterium lamps. Subsequent calibrations at monthly intervals will provide long term tracking of responsivity changes, enabling real solar variability during the descending phase of the solar cycle to be separated from instrumental degradation effects.

© 1991 Optical Society of America