Carl A. Wirtanen

Carl Alvar Wirtanen ( born November 11, 1910 in Kenosha, (Wisconsin, USA); † 7 March 1990 in Santa Cruz ( California)) was an American astronomer.

Wirtanen studied astronomy, physics and mathematics at the University of Virginia. In 1939, he earned his master's degree, and was initially continued at McCormick Observatory of the University of Virginia operates. From 1941 to 1978 he was an employee of the Lick Observatory of the University of California at Mt Hamilton ( California), during which he participated with a break during World War II to research on ballistics. Wirtanen was at the Lick Observatory observer and research assistant, and supported several large observational programs.

Wirtanen discovered five comets, one of which is probably the most famous of the periodic comet 46P/Wirtanen, and eight asteroids. Together with Charles Donald Shane, then director of Lick Observatory, he created a count of about 1 million galaxies in the northern night sky ( Shane - Wirtanen galaxy count). In a set of 1246 photographic plates that had been originally obtained for the study of proper motions of stars, they counted with the simplest means the galaxies in 1.6 million boxes of 10 × 10 arcmin size and so gained an idea of ​​the large-scale distribution of galaxies in the universe.