TITLE:   GCN CIRCULAR
NUMBER:  18558
SUBJECT: GRB 151027A: Mt. Terskol observatory optical observation
DATE:    15/11/04 10:08:22 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

V. Kozlov (IC AMER, NASU),  M. Andreev (Terskol Branch of INASAN), E. 
Mazaeva (IKI), A. Sergeev (Terskol Branch of INASAN),  A. Volnova (IKI), A. 
Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration:

We observed the field of GRB 151027A (Maselli  et al., GCN 18478) with 
Zeiss-600 telescope of Mt. Terskol observatory in R-filter starting on Oct. 
28 (UT) 21:23:11. We obtained several images in R-filter. The afterglow 
(Maselli et al., GCN 18478; Zheng and  Filippenko, GCN 18479) is clearly 
detected in a combined image. The photometry of the combined image is
following

Date             UT start    t-T0          Filter Exp.      OT      Err
                                      (mid, days)          (s)

2015-10-28 21:23:11 1.7431      R      25*120 19.56  0.12

The photometry is based on nearby USNO-B1.0 stars
USNO-B.1_id R2
1513-0237223 16.66
1513-0237170 15.58
1513-0237251 16.81
1513-0237270 16.78