TITLE: GCN CIRCULAR NUMBER: 12062 SUBJECT: GRB 110530A: optical observations in Mondy observatory DATE: 11/06/03 20:44:08 GMT FROM: Alexei Pozanenko at IKI, Moscow A. Volnova (SAI MSU), E. Klunko (ISTP), A. Pozanenko (IKI) on behalf of larger GRB follow up collaboration report: We observed the optical afterglow of the Swift GRB 110530A (D'Avanzo et al, GCN 12046) with AZT-33IK telescope of Sayan observatory (Mondy) on May, 30 between (UT) 16:06:01 - 19:14:06 (i.e. t0+0.0243 d -- t0+0.1549 days after burst trigger). We took several series of 60 s exposures in R. Optical afterglow is detected in single images in the beginning of the observations while in the end we stacked images in 180 - 300 s combined exposures. The photometry is based on the USNO-B1.0 1519-0265568 star (RA=18 48 15.86, Dec=+61 56 15.0) assuming R=16.08. In particular, the photometry UT (mid time), Exposure, Filter, OT 18:04 5x60 R 20.25 +/- 0.06 18:54 5x60 R 20.58 +/- 0.07 coincide with the photometry reported earlier (Andreev et al., GCN 12052). Preliminary light curve can be found at http://grb.rssi.ru/GRB110530A/GRB110530A_AZT33IK_lc.png One can note a non-monotonous light curve decay with possible rebrightening at 0.03 d and 0.53 d and general power law decay index of about 0.9.