TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5122 SUBJECT: GRB 060512: optical decay DATE: 06/05/13 02:14:27 GMT FROM: Daniele Malesani at SISSA-ISAS,Trieste,Italy D. Malesani (SISSA), S. Piranomonte (INAF-OAR), S. Covino (INAF/OABr), N. Masetti, E. Maiorano (INAF/IASF Bo), A. Magazzu', G. Mainella (INAF/TNG), report on behalf of a larger collaboration: We observed the optical afterglow of GRB 060512 (Cummings et al., GCN 5117) with the 3.6 TNG telescope located in the Canary Islands. Two R-band observations were acquired under good observing conditions, with mean times May 13.018 and May 13.065 UT (1.2 and 2.3 hr after the GRB, respectively). The optical afterglow (Cummings et al., GCN 5117; Mundell & Steele, GCN 5118) is well detected and faded by 0.58 +- 0.04 mag between the two epocs. The inferred decay index is alpha = 0.81 +- 0.06, assuming a flux decay F(t) = K*t^-alpha. We acknowledge significant support from the observing staff at TNG. This message can be cited.