TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3197 SUBJECT: GRB 050408: steepening of the optical decay DATE: 05/04/09 01:29:19 GMT FROM: Alberto Castro-Tirado at LAEFF-INTA M. Jelinek (IAA-CSIC Granada), T. Fathkullin, V. Komarova, T. Sokolova, V. Sokolov, V. Vlasyuk, Yu. Balega (SAO RAS, Russia), S. Guziy (Univ. of Nikolaev), A. de Ugarte Postigo, J. Gorosabel and A.J. Castro-Tirado (IAA-CSIC Granada), report: Further monitoring of the optical source reported by de Ugarte Postigo et al. (GCNC 3192), confirms a steepening of the optical decline, when comparing to the Huang et al. results (GCNC 3196). From the first frame obtained at the 6m SAO RAS telescope on Apr 8, 18:49 UT (this value supersedes the one given on GCN 3192) to the last one (at 21:38 UT), the object has declined significantly, implying a decay index alpha of -1.6 . An ID-chart is posted at: http://sirrah.cz/mates/grb050408.jpg .