Lunar reflectivity from Extreme Ultraviolet Explorer imaging and spectroscopy of the full Moon

We present new imaging and spectroscopic observations obtained with the Extreme Ultraviolet Explorer (EUVE). Our 200 A image shows high contrast (33%) anti complete albedo reversal, i.e., contrast is reversed relative to the Moon in visible light. The high contrast at 200 A suggests the potential of the EUV spectral region for surface compositional studies. The 600 A image is surprisingly bland (< 3% contrast). We derive surface reflectivities (geometric albedos) of individual surface regions for the first time with values of 0.11-0.15% at 200 Angstrom, and 2.5% at. 600 Angstrom. Reflectivities derived from the medium- (MW) and long-wavelength (LW) spectra (140-380 Angstrom and 280-760 Angstrom) show that lunar reflectivity decreases by a factor of approximately 60 over the 700 to 150 Angstrom range. Our data further suggest that the Moon's brightness vs phase may behave differently than at longer wavelengths, and that sur face fluorescence may contribute to the observed EUV brightness.