TITLE: GCN CIRCULAR NUMBER: 1515 SUBJECT: GRB 020812: early time optical observation at Ouda Station DATE: 02/08/21 05:13:06 GMT FROM: Taichi Kato at Kyoto U H. Ohashi, T. Kato, T. Senda, H. Mii, K. Mizuno, Y. Yasaka (Kyoto U) and H. Yamaoka (Kyushu U) report on behalf of VSNET-grb collaboration: "We have performed a full analysis of the R band images of GRB 020812 field taken at Ouda (GCN 1469). Three fields of view (14 arcminutes square) were observed, each of which covered a part of HETE WXM error box (GCN 1468) (http://www.rc.kyushu-u.ac.jp/~yamaoka/GRB020812/FOVouda.gif). The limiting magnitudes are measured by compareing with USNO-A2.0 red magnitudes. "Coverage" shows the percentage of covered area of the HETE WXM error box. FOV 1 2 3 center 20:38:28.8 20:38:21.0 20:38:53.3 R.A. (J2000) -05:17:58 -05:17:24 -05:23:45 Dec. epoch 11:08-12:03 12:05-13:27 13:34-16:59 Aug. 12 UT + exp. 38 73 156 minutes lim.mag 18.9 20.2 21.2 in R coverage 48% 30% 58% remark twilight By the comparison with DSS 2 red image, no new source brighter than the limit of DSS 2 is detected. This message may be cited.