18D/Perrine–Mrkos is a periodic comet in the Solar System, originally discovered by the American-Argentine astronomer Charles Dillon Perrine (Lick Observatory, California, United States) on December 9, 1896. For some time it was thought to be a fragment of Biela's Comet. It was considered lost after the 1909 appearance, but was rediscovered by the Czech astronomer Antonín Mrkos (Skalnate Pleso Observatory, Slovakia) on October 19, 1955, using ordinary binoculars, it was later confirmed as 18D by Leland E. Cunningham (Leuschner Observatory, University of California, Berkeley). The comet was last observed during the 1968 perihelion passage when it passed from the Earth. The comet has not been observed during the following perihelion passages: 1975 Aug. 2 1982 May 16 1989 Feb. 28 1995 Dec. 6 2002 Sept.10 2009 Apr. 17 2017 Feb. 26 The next predicted perihelion passage would be on 2025-Jan-01 but the comet is currently considered lost as it has not been seen since Jan 1969. References External links Orbital simulation from JPL (Java) / Horizons Ephemeris 18D at Kronk's Cometography 18D at Kazuo Kinoshita's Comets 18D at Seiichi Yoshida's Comet Catalog NK 835 18D/Perrine-Mrkos – Syuichi Nakano (2002) Periodic comets 018P 0018 Lost comets 18961209 19551019