The SOLar-STellar Irradiance Comparison Experiment (SOLSTICE) measures the irradiances of a set of standard early-type stars. It measures the irradiance from the sun using the same optics, and the ratio of these irradiances can be used to create a long-term measurement of solar variability in the ultraviolet.
The absolute irradiance of the sun measured by SOLSTICE is based on transfer of the pre-flight calibration from SURF to the stars. The calibration is maintained by repeat measurements of the ensemble of standard stars at selected wavelengths over the course of the mission. This poster will describe the process of converting individual solar and stellar observations into a reliable record of solar variability.