TITLE: GCN CIRCULAR NUMBER: 6204 SUBJECT: GRB 070311: Optical observation. DATE: 07/03/13 23:54:45 GMT FROM: Giuseppe Greco at U Bologna G. Greco (Bologna University), F. Terra (Second University of Roma "Tor Vergata"), C. Bartolini, A. Guarnieri, A. Piccioni (Bologna University), G. Pizzichini (INAF/IASF Bologna), D. Nanni (INAF/OAR and Second University of Rome "Tor Vergata"), G. Clementini (Bologna University), S. Galleti, S. Bernabei (Bologna Observatory) report: We observed the field of GRB 070311 (Mereghetti et al. GCN 6189) with the 152 cm Loiano telescope in the Rc band in clear sky conditions. One 1800 sec exposure was obtained, significantly deeper than the DSS catalogue. The afterglow found by Covino et al.(GCN 6190) is detected with R = 22.3+/0.2 based on the NOMAD catalog. Our obsevation was done on 2007 March 13.792 UT middle exposure time. The image, in which the comparison stars are marked, has been posted in our public directory from where it can be retrieved by sftp using hostname: ermione.bo.astro.it username: publicGRB password: GRB_bo. directory: GRB070311