Heinrich Friedrich Siedentopf (December 1, 1906–November 28, 1963) was a German astronomer and physicist.
He was born in Hannover. In 1930 he became an assistant to Heinrich Vogt, then joined the national observatory in Heidelberg. Between 1940–46 he was a Professor of Astronomy at the University of Jena, and director of the observatory. In 1949 he was a professor at the University of Tübingen,[1] where he later died of a heart attack.
Professor Siedentopf published a total of 146 papers and a textbook. He studied cosmology, stellar convection,[2] photometry and the Zodiacal light.[3] In 1934 he developed an adjustable iris for the Stetson-Schilt photometer, allowing the observer to adjust the light level directed at the astronomical plate.[4][5]
Siedentopf crater on the Moon[6] and the main belt asteroid 5375 Siedentopf were named after him.