27P/Crommelin

Observational history

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, 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, 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 19 November 1928, and confirmed by Harry E. Wood (Union Observatory, 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).

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. 27P/Crommelin was last observed in January 2012, and passed about 1.5 AU from Saturn on 11 July 2015.

The next perihelion will be on 27 May 2039. Near perihelion the comet will be 0.74 AU from the Sun and 1.73 AU from Earth. This is about as far from Earth as the comet can get during perihelion.

On 22 December 2120, it will pass 0.297 AU from Earth.

References

Notes

Citations

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