TITLE:   GCN CIRCULAR
NUMBER:  11166
SUBJECT: GRB 100901A: optical observation at Mt.Terskol
DATE:    10/09/01 18:50:15 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

M. Andreev, A. Sergeev (Terskol Branch of Institute of Astronomy),   A. 
Pozanenko (IKI) on behalf of larger GRB follow up collaboration report:

We started observation of the Swift GRB 100901A (Immler  et al., GCN 11159) 
with the Z-600 telescope of Mt.Terskol observatory in R-filter  on   Sep.01 
(UT) 17:50. In a combined image we clearly detect  the afterglow (Immler et 
al., GCN 11159; Guidorzi et al., GCN 11160; Ivanov et al., GCN 11161; Klunko 
et al., GCN 11162).

Preliminary photometry is based on the reference star USNO-B1.0 
#1127-0027231 RA(J2000) = 01 49 06.78 Dec(J2000) = +22 47 03.3 assuming 
R=15.37:

T0+     Filter, Exposure, OT
(d)                 (s)

0.1821 R     5x60          17.28 +/-0.03

The finding chart can be found at
http://grb.rssi.ru/GRB100901A/GRB100901A_R_100901_Terskol.jpg