TITLE: GCN CIRCULAR NUMBER: 14511 SUBJECT: GRB 130427A: Challis Observatory optical observations DATE: 13/04/30 03:59:05 GMT FROM: Jay Norris at Boise State U. Jay Norris, Daryl Macomb (Boise State U.) report: We observed GRB 130427A with the Challis Observatory's 0.4-m telescope (114.33 deg W, 44.5 deg N, 2165 m elevation) on April 29, 05:58 to 06:22 UT. Using seventeen 10-second frames in the R filter acquired in a clear sky, centered at ~ 06:06 UT, 22.3 hours after the Swift/BAT trigger (GCN 14448), we clearly detected the optical afterglow. Comparison with six stars in the field of view (R = 15.5 to 16.8 mag) yielded an estimate of R = 17.6 mag for the afterglow with uncertainty of ~ 0.15 mag. Further observations were interrupted by clouds. [GCN OPS NOTE(30apr13): Per author's request, the affiliation in the FROM-line was changed to Boise State U.]