IAU circular No. 9146, issued on 2010, May 13, announces the discovery by R. S. McMillan of a new comet on May 12, 2010, with the Spacewatch 0.9-m f/3 reflector at Kitt Peak. After posting on the Minor Planet Center's NEOCP webpage, many observers have commented on the cometary appearance of this 17.5 magnitude object, designated C/2010 J3 (MCMILLAN).
We have been able to confirm this object remotely, through a 0.18-m refractor, f/7.3 + CCD at Tzec Maun Observatory near Mayhill, NM, U.S.A.: on 2010, May 12.4, co-adding of 10 unfiltered exposures, 180-seconds each, show a compact coma about 12" in diameter, with a sharp central condensation; broad tail nearly 20" long toward PA 265 deg.
Our confirming image:
The first and preliminary parabolic orbit for comet C/2010 J3 (MCMILLAN) indicates perihelion Sept. 28, 2010, at about 2.2 AU.
by G. Sostero, E. Guido, L. Donato