TITLE: GCN CIRCULAR NUMBER: 6981 SUBJECT: Optical observations of GRB 071020 DATE: 07/10/23 11:25:46 GMT FROM: AAVSO GRB Network at AAVSO Veli-Pekka Hentunen (Taurus Hill Observatory, Varkaus, Finland) reports to the AAVSO International High Energy Network the following optical observations of GRB071020 (GCN #6949, Holland et al.): Markku Nissinen, Henri Taino and Veli-Pekka Hentunen report the detection of the optical afterglow of GRB 071020 (Holland et al., GCN 6949; Schaefer et al., GCN 6948; Yuan et al., GCN 6951; Xin et al., GCN 6956). The afterglow was observed unfiltered approximately 17 hours post-burst, using a 0.3-meter Meade LX200 at Taurus Hill Observatory. The source was detected with marginal signal to noise at an unfiltered magnitude of 20.9 +/- 0.3, with an observational mid-point time of 2007 October 20, 23:54:37 UT. The magnitude is calibrated relative to GSC 0247201072 (GSC1.2) with a magnitude of 13.54. The afterglow magnitude is consistent with an earlier observation by Xin et al. (GCN 6956) as well as with a later observation by Im et al. (GCN 6970). The AAVSO thanks the Curry Foundation for their continued support of the AAVSO International High Energy Network. [GCN OPS NOTE(23oct07): Per submiter's request, "6979" was changed to "6949" in th 3rd line.]