| Discovery | |
|---|---|
| Discovered by | J.-L. Pons |
| Discovery date | February 23, 1818 |
| Designations | |
| 1818 D1, 1873 V1, 1928 W1, 1956 S1 | |
| Orbital characteristics | |
| Epoch | July 18, 2011 |
| Observation arc | 84 years (1928-2012) |
| Number of observations | 392[2] |
| Aphelion | 17.660 AU |
| Perihelion | 0.748 AU |
| Semi-major axis | 9.204 AU |
| Eccentricity | 0.919 |
| Orbital period | 27.9 yr 27y 10m 2d (perihelion to perihelion) |
| Inclination | 28.96° |
| Last perihelion | August 3, 2011[1][2] February 20, 1984[1] |
| Next perihelion | May 27, 2039[1][2][3] |
Comet Crommelin, also known as Comet Pons-Coggia-Winnecke-Forbes, is a periodic comet with an orbital period of almost 28 years. It fits the classical definition of a Halley-type comet with (20 years < period < 200 years). It is named after the British astronomer Andrew C. D. Crommelin who calculated its orbit in 1930. It is one of only four comets not named after their discoverer(s), the other three being Comets Halley, Encke, and Lexell. It next comes to perihelion (closest approach to the Sun) around May 27, 2039 when it will be near a maximum near-perihelion distance from Earth.