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) in late May/early June 2039. The first observation was by Jean-Louis Pons ( Marseille, France) on February 23, 1818, he followed the comet until February 27 but was prevented further by bad weather. Johann Franz Encke attempted to calculate the orbit but was left with very large errors. In 1872, John R. Hind produced a rough orbital calculation and observed it was close to that of

Comet Biela Biela's Comet or Comet Biela (official designation: 3D/Biela) was a periodic Jupiter-family comet first recorded in 1772 by Montaigne and Messier and finally identified as periodic in 1826 by Wilhelm von Biela. It was subsequently observed to ...

, based on these observations, Edmund Weiss later speculated it may have been part of Biela's comet. The next observation was on November 10, 1873, by Jérôme E. Coggia ( Marseille, France), and again on November 11 by Friedrich A. T. Winnecke (

Strasbourg Strasbourg (, , ; german: Straßburg ; gsw, label=Bas Rhin Alsatian, Strossburi , gsw, label=Haut Rhin Alsatian, Strossburig ) is the prefecture and largest city of the Grand Est region of eastern France and the official seat of the Eu ...

, France), but it was lost by November 16. Weiss and Hind took up the calculations and tried to match it again with the 1818 appearance. A third discovery was by Alexander F. I. Forbes ( Cape Town, South Africa) on November 19, 1928, and confirmed by Harry E. Wood (

Union Observatory Union Observatory also known as Johannesburg Observatory ( 078) is a defunct astronomical observatory in Johannesburg, South Africa that was operated between 1903 and 1971. It is located on Observatory Ridge, the city's highest point at 1,808 met ...

, South Africa) on November 21. It was Crommelin who eventually established the orbit and finally linked the 1818 (Pons) and 1873 (Coggia-Winnecke) comets to it ''(also see

Lost comet A lost comet is one which was not detected during its most recent perihelion passage. This generally happens when data is insufficient to reliably calculate the comet's location or if the solar elongation is unfavorable near perihelion passage. T ...

)''. On its latest return, 27P/Crommelin was recovered on May 12, 2011, at apparent magnitude 18.7 and peaked at magnitude 10.7 at perihelion on August 3.

References

External links

Orbital simulation
from JPL (Java)
Horizons Ephemeris

27P/Crommelin
at the

Minor Planet Center The Minor Planet Center (MPC) is the official body for observing and reporting on minor planets under the auspices of the International Astronomical Union (IAU). Founded in 1947, it operates at the Smithsonian Astrophysical Observatory. Function ...

's Database
27P at Kronk's Cometography

Lightcurve
* 27P as seen by 10
GRAS-04
o
2011-05-30
(60 sec x 8) * 27P as seen by 20" RCOS o
2011-07-10
(30 sec x 12; Joseph Brimacombe) Periodic comets Halley-type comets 0027 027P Comets in 2011 18180223 {{comet-stub