TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4090 SUBJECT: GRB050805A: Rc optical observations DATE: 05/10/12 19:46:11 GMT FROM: Graziella Pizzichini at IASF/CNR,Bologna GRB050805A: optical observations D. Nanni, (INAF/Osservatorio di Roma), F. Terra (CRATI scrl, and Cosenza University), C. Bartolini, G. Greco, A. Guarnieri, A. Piccioni (Bologna University), S. Marinoni, A. De Blasi (INAF/Osservatorio di Bologna) and G. Pizzichini (INAF/IASF, Bologna) report: We observed the error box of possible GRB050805A (Swift trigger 149118) with the 152 cm Loiano Telescope and the BFOSC camera system in good sky conditions. We obtained the following images, all of them in the Rc filter: Start time (UT) Duration (min) 050805 22:24:05 10 050805 22:44:13 10 050805 23:09:17 20 050805 23:34:36 20 050806 02:07:02 20 050806 02:29:00 20 We do not detect the optical candidate cited by Lipunov et al., GCN 3767. At its location the 3 sigma magnitude limit in our coadded images is 22.5 . The coadded images and the observation log will be posted in our public directory from where they can be retrieved by sftp using hostname: ermione.bo.astro.it, username: publicGRB, password: GRB_bo, directory: GRB050805A. [GCN OPS NOTE(12oct05): The SUBJECT line was changed from "040825A" to "050805A".]