| next_p=June 8, 2059[3][4]
}}23P/Brorsen–Metcalf is a periodic comet with an orbital period of 70 years. It fits the classical definition of a Halley-type comet with (20 years < period < 200 years).[ It was first discovered by Theodor Brorsen at the Altona Observatory on July 20, 1847, and again by Kaspar Schweizer (Moscow) on August 11, 1847. It was predicted that it would reappear between 1919 and 1922.]
On August 21, 1919, the comet was recovered by Joel Hastings Metcalf (Camp Idlewild, Vermont, United States) as 8th magnitude. Additional discoveries were made by Edward Barnard (Yerkes Observatory, Wisconsin, United States) on August 22, Michel Giacobini (Paris, France), Ostrovlev (Theodosia, Crimea) and Selavanov (Saint Petersburg). By the end of September 1919 it was confirmed as being the same as Brorsen's comet.
References
1. ^1 {{cite web |author=Horizons output |url=http://ssd.jpl.nasa.gov/horizons.cgi?find_body=1&body_group=sb&sstr=23P |title=Observer Table for Comet 23P/Brorsen-Metcalf (1989) |accessdate=February 19, 2012}} (Observer Location:@sun)
2. ^1 {{cite web |date=2005-11-09 |title=23P/Brorsen-Metcalf |publisher=Seiichi Yoshida's Comet Catalog |author=Seiichi Yoshida |url=http://www.aerith.net/comet/catalog/0023P/index.html |accessdate=February 19, 2012}}