6.1	Imaging Spectrograph Characterization and Calibration
The imaging spectrograph (ISG) will have to be characterized in terms of the sensitivity of the instrument to light of different wavelengths and in terms of the effect that the optics have on the path light of various wavelengths and at various angles of incidence takes through the instrument.  The sensitivity of the instrument as a function of wavelength will be acccomplished using the monochromator available through the ISAS optics laboratory.  This instrument generates monochromatic light with a spectral purity of *** and with a spectral resolution of ***. Theoretical paths through the instrument may be modelled using ray-tracing software owned by SCI-TEC.  Investigation of the effect that angle of incidence will have on the path of light through the instrument, using the actual instrument, may be accomplished with novel modifications to the existing monochromator. However, such an approach may not be possible and therfore testing of this aspect of the instrument response may have to be done at a third party facility.

The method of inversion used will cause the data collected from the ISG to be self-calibrating.  By taking the ratio of the initial intensity of a star and the subsequent intensity measured along a different optical path an absolute calibration of the instrument is unnecessary.