Holt, Henry E.; Jordan, J. A.; http://viaf.org/viaf/94939284 (U.S. Geological Survey, Center of Astrogeology, 1972-01)
The Apollo 16 gnomon was photometrically calibrated at the Manned Spacecraft Center, Texas during December 2-3, 1971. The principal objective of the photometric calibrations is to permit the measurement of photometric ...