TITLE: GCN CIRCULAR NUMBER: 9820 SUBJECT: GRB 090813: I-band observations from 1.5m OSN telescope DATE: 09/08/17 15:09:25 GMT FROM: Javier Gorosabel at IAA-CSIC J. Gorosabel (IAA-CSIC), A. de Ugarte Postigo (INAF-OAB), A. Sota (IAA- CSIC), S. Guziy (IAA-CSIC), M. Jelinek (IAA-CSIC), P. Kubanek (IAA- CSIC & IPL Univ. Valencia), A.J. Castro-Tirado (IAA-CSIC), report; We performed I-band observations of the GRB 090813 optical afterglow (Gorosabel et al. GCN 9782; Cenko et al. GCN 9783; Smith et al. GCN 9784) with the 1.5m telescope of Observatorio de Sierra Nevada. The observations were carried on Aug 13.8979 - 13.9667 UT with a total exposure time of 4950 seconds. No object brigther than I = 21.9 was detected at the afterglow position.