TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4953 SUBJECT: GRB060403: Optical Limit DATE: 06/04/05 02:28:16 GMT FROM: Adalberto Piccioni at Astronomy, Bologna U. F. Terra, (Second University of Roma "Tor Vergata"), C. Bartolini, G. Greco, A. Guarnieri, A. Piccioni (Bologna University), D. Nanni (INAF/OAR and Second University of Roma "Tor Vergata"), S. Galleti, R. Gualandi (INAF Bologna) and G. Pizzichini (INAF/IASF Bologna) report: Using the 152 cm Loiano telescope equipped with the BFOSC camera system, we obtained in poor sky conditions (seeing = 2.7 arcsecs) two Rc-band images (2 x 900 sec) of the field of the GRB060403 (Boyd et al., GCN 4945, Mangano et al., GCN 4947) starting at April 4.0778 and 4.0898 respectively. A preliminary comparison with the DSS-2 does not reveal any new source brighter than the DSS-2 limit within 1' from the XRT location. Our co-added image reaches a detection limit slightly deeper than Rc=19. The Rc co-added image 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.