Observation planning to better track Solar instrument degradation

Solar observations are intrinsically harsh to optics and detectors. Space measurements in particular expose the spacecraft and payload to charged particles and UV radiation which causes changes in the transmission profile of windows and optics. These affect the absolute accuracy of the measurements over time. Astronomical observations typically rely on standard stars and calibration sources to track and correct changes in the instrument. This method was used with the SORCE-SOLSTICE instrument during its 17 year Solar Spectral Irradiance (SSI) measurement record covering more than 9 orders of magnitudes in brightness between stellar and Solar observations. Other instruments are designed with multiple identical channels which are used at various cadence to track degradation differentially. We present the advantages and issues discovered with each method and the benefits of following a constant and regular observation plan to improve the accuracy of the degradation corrections.