TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5192 SUBJECT: GRB060526, optical observations DATE: 06/05/31 18:48:03 GMT FROM: Adalberto Piccioni at Astronomy, Bologna U. F. Terra (Second University of Roma "Tor Vergata"), G. Greco, C. Bartolini, A. Guarnieri, A. Piccioni (Bologna University), D. Nanni (INAF/OAR and Second University of Roma "Tor Vergata"), I. Bruni, S. Galleti (Bologna Observatory) and G. Pizzichini (INAF/IASF Bologna) report: "We observed the field of GRB 060526 (Campana et. al., GCN 5162) with the 152 cm Cassini Telescope located in Loiano, equipped with BFOSC in the nights april 26-27 (seeing 2".0) and 27-28 (seeing 1".7). The photometry is based on the SDSS stars (Cool et al. GCN 5164) and trasformation derived from Lupton (2005). Using this transformation we find for the USNO B-1 star (RA = 15 31 18.6, DE = +00 17 34.9) the magnitude Rc = 16.50, consistent with the calibration of Khamitov et al. (GCN 5177). We find the following magnitudes: Mean...UT .......Filter........Exptime (s).......magnitude May...26.908........Rc............900............18.85+/-0.08 May...26.921........Rc............900............18.92+/-0.07 May...26.935........V............1200............19.37+/-0.08 May...26.949........I.............900............18.60+/-0.06 May...26.961........Rc............900............19.08+/-0.07 May...26.975........V............1200............19.64+/-0.09 May...26.990........I.............900............18.80+/-0.06 May...27.002........Rc............900............19.28+/-0.09 May...27.017........V............1200............19.79+/-0.11 May...27.031........I.............900............18.94+/-0.08 May...28.002........Rc............900............20.61+/-0.13 May...28.017........Rc............900............20.44+/-0.10