Comets - 186P/Garradd - 0186P
Type Periodic Perihelion Date 21 May 2019 Perihelion Distance (q) 4.4 Aphelion Distance (Q) 5.6 Period (Years)   11.1 Eccentricity (e)   0.12 Inclination (i)   28.5 Click for NASA orbit diagram
Hills Observatory: 1 January 2013 to 6 May 2018
G. J. Garradd (Siding Spring Observatory, New South Wales, Australia) discovered this comet on images obtained on 2007 January 25 using the 0.5-m Uppsala Schmidt and a CCD camera. The three images indicated a magnitude of 18.0-18.3. In late February, M. Meyer (Germany) announced that he had found three prediscovery images on Siding Spring Observatory Digital Sky Survey images from 1975 and 1996. He had been slightly adjusting the early orbits that were calculated when he found an image of the comet on a plate exposed on 1996 February 26. The magnitude was given as 17.8. The orbit improvement brought about by this position then enabled Meyer to locate the comet on images exposed on 1975 May 31 and June 3. The magnitude on these images was given as 15.5. In linking all of these positions, G. V. Williams (Central Bureau for Astronomical Telegrams) found that comet images reported on IAU Circular No. 3247 (1978 Jul. 25) by R. D. Eberst also belonged to this comet. The images were also exposed at Siding Spring Observatory, using the 1.2-m UK Schmidt, on 1977 July 18 and 19. The magnitude was given as 18, while a tail extended about 3'. Although it usually reaches 17.5 mag at best, the comet was unexpectedly bright at 15.5 mag in 1975 May and June. It seems to have been a temporary outburst, as the comet returned to its normal brightness in 1977 July at 18 mag. This comet is similar to 111P/Helin-Roman-Crockett; large perihelion distance, almost circular orbit, and a record of unexpected brightening in temporary outburst. Date 10x10 mag Error Kphot mag Coma ' 02-May-16 19.49 0.21 19.2 0.2 22-Jan-18 18.62 0.05 18.0 0.2 14-Feb-18 18.28 0.08 16.9 0.3 21-Feb-18 18.20 0.05 18.0 0.2 11-Mar-18 18.01 0.03 17.6 0.2