There will be several state-of-the-art spectrometers in operation on the NASA Polar Orbiting Platform (NPOP-1) as part of the Earth observing system (Eos). The moderate resolution imaging spectrometer (MODIS) will consist of two imaging spectroradiometric instruments, one nadir viewing (MODIS-N) and the other tiltable (MODIS-T), for ocean observation and land bidirectional reflectance studies. The moderate resolution imaging spectrometer-tilt (MODIS-T) instrument is presently being constructed for flight on the EOS. It is an imaging spectrometer utilizing a grating type, reflecting Schmidt optical design that must provide a 1.1 km cross-track swath and a +/- 50 deg forward and aft tilt capability. The instrument is required to cover the wavelength range from 400 to 880 nm in approximately 15 nm steps with less than 2.3 instrument induced polarization. The absolute radiometric accuracy must be at least 5 over the full dynamic range of the instrument.
Thomas J. Magner,
"Moderate-resolution imaging spectrometer-tilt baseline concept", Proc. SPIE 1492, Earth and Atmospheric Remote Sensing, (1 September 1991); doi: 10.1117/12.45855; https://doi.org/10.1117/12.45855