Henry E. Holt (27 September 1929 - 5 May 2019)^[2] was an American astronomer and prolific discoverer of minor planets and comets, who has worked as a planetary geologist at the United States Geological Survey and Northern Arizona University.^[3]

In the 1960s he studied the photometric properties of the lunar surface as part of the Surveyor and Apollo programs.^[3]

Between 1989 and 1993, he has discovered nearly 700 minor planets, and ranks among the Top 30 discoverers in MPC's list.^[1] His discoveries including the potentially hazardous asteroid 4581 Asclepius, the numbered asteroid that has made the closest approach to Earth at the time,^[3] as well as the near-Earth asteroid 4544 Xanthus, and the main-belt asteroid 6312 Robheinlein, which he named after famous science fiction author, Robert Heinlein.^[4] He is also a co-discoverer of the three periodic comets 121P/Shoemaker-Holt, 127P/Holt–Olmstead (discovered with C. Michelle Olmstead), and 128P/Shoemaker-Holt.^[5]

The Mars-crossing asteroid 4435 Holt was named in his honor.^[3] The official naming citation was published by the Minor Planet Center on 30 January 1991 (M.P.C. 17656).^[6]

Minor planet 4582 Hank is named after his son, Henry Reid Holt. ^[7]

Henry Holt made some of his discoveries in collaboration with: ^A Norman G. Thomas, ^B David Levy, ^C Jeffery A. Brown, ^D , and Carolyn Shoemaker

• List of minor planet discoverers § H. E. Holt