TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3192 SUBJECT: GRB 050408 optical candidate DATE: 05/04/08 20:24:33 GMT FROM: Alberto Castro-Tirado at LAEFF-INTA A. de Ugarte Postigo (IAA-CSIC Granada), V. Komarova, T. Fathkullin, T. Sokolova, V. Sokolov, V. Vlasyuk, Yu. Balega (SAO RAS, Russia), S. Guziy (Univ. of Nikolaev), M. Jelinek, J. Gorosabel and A.J. Castro-Tirado (IAA-CSIC Granada), report: Following the detection by HETE-2 of the long X-ray gamma- ray burst GRB 050408 (Sakamoto et al., GCN 3189), we have taken R-band images at the 1m and 6m telescope at the Special Astrophysical observatory starting at 20.25 UT (i.e. 3.9 hr after the event). Within the X-ray error box provided by SWIFT/XRT (Wells et al. GCN 3191), we identify three point-like sources. The brightest one (R = 20.5) is at preliminary coordinates RA(2000) = 12 02 17.32, Dec(2000) = +10 51 10 (error 1"), which we identify at the potential GRB 050408 optical afterglow. The object does not appear in the corresponding DSS-2 plate. Further observations are in progress. We thanks the SAO RAS director Yu. Balega for his support for the SAO RAS GRB ToO programme.