110P/Hartley
Comet Hartley 3 is a periodic comet with a six-year orbit around the Sun. It is one of ten comets discovered by Australian astronomer, Malcolm Hartley.
Observational history
Discovery
The comet appeared as a weak trail at magnitude 16.5 on the edge of its discovery plates, which were taken from the UK Schmidt Telescope of the Siding Spring Observatory. By 22 February, Hartley confirmed his discovery using the same telescope, and found a tail about 10 arcminutes in length. From the Palomar Observatory, both Carolyn and Eugene Shoemaker found two precovery images of the comet about 4.8 hours before its official discovery. By then, it was determined that Hartley's find is definitely a short-period comet.Follow-up observations
Six observatories around the globe made observations of Hartley 3 in March 1988, including those made by Tsutomu Seki, Robert H. McNaught, James V. Scotti, and David H. Levy. By April 1988, revised orbital calculations by Brian G. Marsden indicated that the comet completes an elliptical orbit once every 6.85 years.Hartley 3 was successfully recovered by James V. Scotti using the Spacewatch telescope of the Kitt Peak Observatory on 23 June 1993.