TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3319 SUBJECT: GRB 050401: Rc observation DATE: 05/04/27 15:23:16 GMT FROM: Corrado Bartolini at Universita di Bologna G. Greco, C. Bartolini, A. Guarnieri, A. Piccioni (Bologna University), G. Pizzichini (IASF-CNR, Sezione di Bologna), S. Bernabei and S. Marinoni (Osservatorio di Bologna) report: "We observed the optical afterglow (Mc Naught and Price, GCN 3163) of the Swift GRB050401 (Angelini et al. GCN 3161) with the 152-cm G. D. Cassini telescope of Bologna University equipped with the BFOSC CCD imager. We obtained 2x1800s Rc images on 2005 April 2.056 and April 2.092 UT. From the first image, in good sky conditions (seeing about 2"), we find Rc =3D 22.7 +- 0.4, using the calibration kindly provided to us by P. D'Avanzo and N. Masetti, performed at TNG telescope. In the second image, less deep, the object is hardly visible. The first image of the OT is posted into a public directory from where it can be retrieved by sftp using hostname: ermione.bo.astro.it username: publicGRB password: GRB_bo directory: GRB050401".