IAUC nr.9214, issued on 2011, June 06, announces the discovery of a new comet (discovery magnitude 16.3) by Robert H. McNaught through the 0.5-m Uppsala Schmidt + CCD at Siding Spring, on images obtained on 2011, June 3.7. The new comet has been designated C/2011 L3 (McNAUGHT).
After posting on the Minor Planet Center's 'NEOCP' webpage, this object has been found by several CCD astrometrists to show cometary appearance. We performed some follow-up measurements of this object while it was still listed in the NEOCP. Stacking of 30 unfiltered exposures, 60-sec each, obtained remotely on 2011, June 05.4 from the GRAS Observatory (near Mayhill, NM) through a 0.25-m, f/3.4 reflector + CCD, shows that this object is a comet: strong central condensation and coma nearly 25-arcsec in diameter elongated toward PA 230.
Our confirming image (click for a bigger version):
M.P.E.C. 2011-L28 assignes the following preliminary orbital elements to comet C/2011 L3: T Aug. 10.35; e= 1.0; Peri. = 27.63; q = 1.92 AU; Incl. = 87.09
IAUC nr.9212 & IAUC nr.9213 issued on June 06, 2011 reports the discovery by R. H. McNaught of 2 more comets: C/2011 L1 (MCNAUGHT) & C/2011 L2 (MCNAUGHT). So, according to COCD webpage, C/2011 L3 is the 62th comet discovery for Robert H. McNaught.
by Ernesto Guido & Giovanni Sostero