C/2011 Y3 (Boattini) was discovered by Andrea Boattini on 2011, Dec. 25.24 with the 1.5-m f/2 reflector + CCD from Mount Lemmon Sky Survey (part of the Catalina Sky Survey). He described the comet as being very diffuse with central condensation: four 30-s exposures show a 6″ coma and a wide fan-shaped tail about 30″ long in p.a. 240-245 deg.
It was subsequently placed on the NEO Confirmation Page, where other observatories (including me at 204, H. Sato from I89-Nerpio, R. Holmes et al. from H21-ARI, P. Bacci et al. from 104-San Marcello Pistoiese, A. Novichonok et al. from C32-TAU station of Ka-Dar Observatory, R. Ligustri from H06-RAS and J. Lacruz from J87-La Canada) confirmed its cometary appearance.
I observed it less than 18 hours after the discovery: conditions were good so it was quite easy to confirm it as a comet. I measured a very diffuse 10″ coma and a broad tail at least 25″ long in p.a. around 250 deg.
Results were published in CBET 2959 (subscription required) and astrometry, together with preliminary parabolic orbital elements, in MPEC 2011-Y50.
This marks the 21st comet discovery for Andrea Boattini!
Here is the image: