TITLE: GCN CIRCULAR NUMBER: 9448 SUBJECT: GRB 090529: OSN optical observations DATE: 09/05/30 16:04:33 GMT FROM: Javier Gorosabel at Danish Space Res Inst J. Gorosabel (IAA-CSIC), A. de Ugarte Postigo (ESO, Santiago), F.J. Aceituno (OSN, IAA-CSIC), A.J. Castro-Tirado (IAA-CSIC), report on behalf of a larger collaboration: "We carried out R-band observations of the GRB 090529 XRT error circle (Sakamoto et al. GCN 9430; Osborne et al. GCN 9433) with the 1.5m OSN telescope. On May 29.87-29.93 UT (0.27-0.33 days afer the GRB) we detected the optical afterglow (Xin et al. GCN 9431) at R=21.44+/-0.06, against the same reference star used by Kann et al. (GCN 9436)." This message can be quoted.