president of the Astronomical Society of the Pacific. In 1956, he used the 60" reflector at the Mount Wilson Observatory to observe a peculiar obscuration on part of the floor of Alphonsus crater, which brought him worldwide notice. (This is a class of events now called a transient lunar phenomenon.) During 1958, he reached mandatory retirement age, and was officially retired on March 31 and was succeeded by Clarence H. Cleminshaw, who had been associate director of the observatory. However, he remained active during his retirement, writing several books on astronomy and performing consulting services. He also served as Director Emeritus for the Griffith Observatory. Awards and honors Fellow of the Royal Astronomical Society. Guggenheim Fellowship scholarship, 1929–1930. Honorary doctorate, Monmouth College, 1941. G. Bruce Blair Award, 1958. Pendray Aerospace Literature Award, 1965. The crater Alter on the Moon is named after him. Selected works Alter, Dinsmore. Application of Marvin's Periodocrite to Rainfall Periodicity. Lawrence, Kan: University of Kansas, 1920. Alter, Dinsmore. "A Critical Test of the Planetary Hypothesis of Sun Spots," Monthly Weather Review, 1929, April. Alter, Dinsmore, & Clarence H. Cleminshaw, "Palomar observatory", Los Angeles, Griffith Observatory. Alter, Dinsmore. Introduction to Practical Astronomy, New York, Crowell, 1933. Alter, Dinsmore. Introduction to the Moon, Los Angeles, Griffith Observatory, 1958. Alter, Dinsmore. Pictorial Guide to the Moon, London, Arthur Barker Ltd., 1963. Alter, Dinsmore. Lunar Atlas, North American Aviation, 1964. Alter, Dinsmore, Clarence H. Cleminshaw, and John G. Phillips, Pictorial astronomy, New York, Crowell, 1974. References External links Inconsistent Moonby Joseph H. Jackson, produced for "Analog", October 1964. Mr. Pitt's Telescope: A Short History of the 27-Inch Reflector at the University of Kansasby D. J. Bord, 1980. 1888 births 1968 deaths Westminster College (Pennsylvania) alumni University of Pittsburgh alumni University of Alabama faculty UC Berkeley College of Letters and Science alumni University of Kansas faculty California Institute of Technology faculty People from Colfax, Washington American astronomers People from Los Angeles United States Army officers Military personnel from California