IAU Circular nr.9071, issued on 2009, Sep. 10, announces the discovery of a new comet by R. H. McNaught, named C/2009 R1 (McNAUGHT). It was found on Sep. 09 in the course of the Siding Spring Survey with the 0.5-m Uppsala Schmidt telescope. Pre-discovery Uppsala Schmidt images taken by G. J. Garradd and McNaught on July 20, Aug. 1, and 18 have been identified by T. Spahr and B. G. Marsden in astrometry submitted to the Minor Planet Center.
After posting on the Minor Planet Center's 'NEOCP' webpage, other observers have noted the cometary appearance of this 17.5 magnitude object.
We have been able to confirm this object remotely, through the GRAS network, using a scope located in Mayhill (NM): on 2009, September 10.2, co-adding of 20 unfiltered exposures, 120 seconds each, obtained by means of a 0.25-m, f/3.4 reflector + CCD, show a coma of diameter about 12" with a hint of elongation toward p.a. 65 deg.
Our image is available here:
The preliminary orbit for comet C/2009 R1 (McNAUGHT) indicates perihelion on Jul. 02, 2010, at about 0.4 AU: http://www.cfa.harvard.edu/mpec/K09/K09R33.html
This comet may reach magnitude 5 at the end of June 2010, but the elongation will be very small (only 18 degree on June 27, 2010) and so the observing conditions.
This is the comet discovery number 51 for Robert McNaught.
UPDATE MAY 30, 2010
Please see our last post about this comet:
by Ernesto Guido & Giovanni Sostero