2011 AH5 was discovered by Steve Larson (during the course of the Catalina Sky Survey) on 2011, Jan. 08.34 with the 0.68-m Schmidt on Mt.Bigelow.
From our site the first clear night after its discovery was yesterday (between 11 and 12 of January) and it was on my target list. On that night there was also a request from Lance Benner of NASA radar team, because they planned to observe it with Goldstone the following day.
At the time of the image, 2011 AH5 was moving at 53″/min in constellation Canes Venatici at magnitude 17.9 R, heading toward closest approach to the Earth on Jan. 13 around 09 UTC, at a distance of 0.0086 AU (less than 1.3 million Km or 3.3 LD). From the H value its diameter should be around 20-40m.
Let’s wait for some images from the radar guys!
"G.V.Schiaparelli" Astronomical Observatory 
According to the IAU, the designation of comet Larson is 2011 A1, not 2011 AH5.
Dear Jean, in fact my observation refers to NEO 2011 AH5, not P/2011 A1 (Larson).