TITLE:   GCN CIRCULAR
NUMBER:  21471
SUBJECT: GRB 170810A: AbAO optical upper limit
DATE:    17/08/13 19:29:38 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

A. Volnova  (IKI),  A. Pozanenko (IKI), R. Inasaridze (AbAO),  V. Ayvazian 
(AbAO),  O. Kvaratskhelia (AbAO), G. Inasaridze (AbAO), E. Mazaeva (IKI), 
I. Molotov (KIAM) report on behalf of larger GRB follow-up  collaboration:

We observed the field of the Swift  GRB 170810A (Gibson  et al., GCN 21450) 
with AS-32 (0.7m) telescope of Abastumani Observatory starting on August, 11 
(UT)  17:02:09. We obtained several unfiltered images of the field.   Within 
enhanced XRT error circle  (Goad et al., GCN   21451) we do not detect  the 
afterglow (Rebolo et al, GCN 21449; Gibson  et al., GCN 21450). Preliminary 
photometry of the field is following

Date        UT start         t-T0            Filter Exp.   OT   Err UpLim (3 
sigma)
                       (mid, days)                         (s)

2017-08-11 17:02:09  0.80915   CR     33*20  n/d  n/d 18.2


Photometry is based on nearby SDSS stars  (Lupton transformation)

SDSS id                           R_Lupton
J123141.98+033552.6 15.637 0.013
J123153.09+033552.7 14.800 0.012
J123154.00+033945.4 15.540 0.013