Loyal Blaine Aldrich

Loyal Blaine Aldrich (November 20, 1884 – February 11, 1965) was an American astrophysicist and astronomer of the Smithsonian Institution. Upon graduation from the University of Wisconsin in 1907, Aldrich became a Smithsonian Astrophysical Observatory assistant to Charles Greeley Abbot. The observatory conducted astrophysical research on solar radiation and the amount of energy from the Sun that strikes the outer edge of the Earth's atmosphere. Abbot became director of the observatory in 1907 and established solar observing stations in the United States, South America, and Africa to carry out research on solar radiation. Aldrich became director of the observatory from 1942 to 1955. Harvard University astronomy department chairman Fred Lawrence Whipple became director of the observatory when Aldrich retired.

Studies Aldrich assisted Abbott's mapping of the infrared solar spectrum and carried out systematic studies of variation in solar radiation, its relation to the sunspot cycle, and its effect on weather variation. He also studied the nature of atmospheric transmission and absorption and assisted Abbot perfecting various standardised instruments now widely used for measuring the Sun's heat. New evidence on the intensity of solar radiation outside the atmosphere (1915 with Abbot & Frederick E. Fowle) The pyranometer : an instrument for measuring sky radiation (1916 with Abbot) On the use of the pyranometer (1916 with Abbot) On the distribution of radiation over the sun's disk and new evidences of the solar variability (1916 with Abbot & Fowle) The Smithsonian eclipse expedition of June 8, 1918 (1919) The reflecting power of clouds (1919) The melikeron - an approximately black-body pyranometer (1922) The distribution of energy in the spectra of the sun and stars (1923 with Abbot & Fowle) A study of body radiation (1928) An improved water-flow pyrheliometer and the standard scale of solar radiation (1932 with Abbot) Supplementary notes on body radiation (1932) The standard scale of solar radiation (1934 with Abbot) Smithsonian pyrheliometry and the Andean volcanic eruptions of April 1932 (1944) The solar constant and sunspot numbers (1945) Smithsonian pyrheliometry and the standard scale of solar radiation (1948 with Abbot) Energy spectra of some of the brighter stars (1948 with Abbot) The Abbot silver-disk pyrheliometer (1949) Note on Fowle's spectroscopic method for the determination of aqueous vapor in the atmosphere (1949)