The ground calibration of SIM consists of a number of component level activities that are combined to produce the SIM measurement equations, the flow diagram for this process is shown on the left. These activities include:
- Measurement of the SIM ESR optical efficiency at the NIST SIRCUS facility. This is an ongoing calibration activity that is conducted with SIM flight spare components.
- Establish the instrument’s wavelength scale using atomic lines of mercury and a Schott BG-20 glass filter that has it wavelength scale tied to the wavelength scale of the National Solar Observatory’s Fourier transform spectrometer at Kitt Peak Observatory.
- The transmission of the prism glass as a function of wavelength and polarization.
- Measurement of the spectrometer’s instrument function with a wavelength stabilized laser and ray tracing models.