Comparison of thermal emission spectroscopic measurements of the lunar surface - 1968-1990

Four sets of spectra of resolved locations on the lunar surface obtained by Earth-based telescopes since 1968 are compared. The results obtained show that there is good consistency among the datasets within limits of signal-to-noise, and that ranges of overlap in wavelength and major spectral differences due to both the Christiansen emission peak and reststrahlen bands can be detected in remote measurements of the moon in the thermal infrared wavelength region. The conclusion of Goetz (1968) that only minor differences exist on the lunar surface in the region of thermal emission is found to be incorrect. Direct comparison of the four highest quality spectroscopic experiments in the region of thermal emission from 7 to 14 microns, which collected spectra of spatially resolved locations on the lunar surface, shows that this wavelength region reveals major spectral differences among lunar locations.