TITLE: GCN CIRCULAR NUMBER: 4420 SUBJECT: GRB 051221B: Optical Observations with Kuiper 1.54m DATE: 05/12/30 21:41:55 GMT FROM: Peter A. Milne at Super-LOTIS P.A.Milne (Steward Obs), on behalf of the Super-LOTIS GRB team reports: We observed the field of GRB 051221B (SWIFT-BAT trigger 173904) on Dec. 21, 2005, starting at UT=02:35:53 (06:32:33 after the burst) with the 61" Kuiper telescope at Mt. Bigelow, AZ. We obtained 11 x 300-sec R-band images. Observing conditions were considered good. The field was subsequently observed the next night starting at UT=01:33:50. We obtained 7 x 300 second images in the R-band on the second night. Inspection of a subtraction image produced from co-added images reveals no fading source at the location of the candidate optical counterpart reported by Halpern & Tyagi (GCN 4381). The limiting magnitude of the co-added image taken on the first night is roughly 23.0 magnitude. This message may be cited.