TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3794 SUBJECT: GRB 050813: KAIT optical limit DATE: 05/08/13 19:16:50 GMT FROM: Weidong Li at UC Berkeley KAIT/LOSS W. Li, University of California, Berkeley, on behalf of the KAIT GRB team, report: "The robotic 0.76-m Katzman Automatic Imaging Telescope (KAIT) at Lick Observatory observed GRB050813 detected with Swift (Trigger 150139; Retter et al. GCN 3788, Sato et al. GCN 3793). A series of images was automatically obtained from 06:45:49 UT (39s after the burst) to 07:20:36 UT (2126s after the burst). The sequence includes a combination of images taken with the V and I filters, as well as some that are unfiltered. We did not detect a new object in our images when compared to the DSS II images. In particular, no new object was found within the error circle of the Swift XRT position as reported by Morris et al. (GCN 3790). Our first 20s unfiltered image started at 39.2s after the burst has a limiting magnitude of about 18.6 when compared to the USNO-B1.0 catalog." This message may be cited.