TITLE:   GCN CIRCULAR
NUMBER:  14806
SUBJECT: GRB 130606A: AAO optical observations
DATE:    13/06/07 13:22:00 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

A. Volnova (IKI), R.Inasaridze (AAO), O. Kvaratskhelia (AAO), V. 
Ayvazian(AAO), Yu. Krugly (IA KhNU),  I. Molotov (KIAM), A. Pozanenko 
(IKI)  report on behalf of  larger GRB follow-up collaboration:

We observed the field of the Swift Swift GRB 130606A (Ukwatta et al., 
GCN 14781)with AS-32 (0.7m) telescope of Abastumani Observatory, 
starting on Jun. 06 (UT) 21:47:43. We obtained several unfiltered images 
of 180 s exposure. The afterglow (Jelinek et al., GCN 14782; Xu et al., 
GCN 14783; Nagayama et al., GCN 14784) is well detected in  separate 
images. Preliminary photometry

T_start,   Exp,  T-t0, d    OT +/- err
  UT        s     mid, days
21:47:43   180   0.03095    18.84 +/- 0.05
21:51:24   180   0.03351    18.86 +/- 0.04
21:55:04   180   0.03605    18.95 +/- 0.05
21:58:45 2x180   0.03988    19.16 +/- 0.06

is based on SDSS stars R mag, where R mag obtained via transformations 
ugriz in BVRI (Lupton, 2005):

SDSS                 u     g       r     i      z       R
J163722.96+294541.6 16.747 15.352 14.827 14.598 14.568  14.625
J163734.99+294356.8 18.166 17.023 16.665 16.540 16.503  16.493