[AAVSO-HEN] GRB 091208B: optical observations

[grb at aavso.org]

The following is a GCN Circular circulated via the AAVSO network.
For an archive and more information on circulars visit:
http://lheawww.gsfc.nasa.gov/docs/gamcosray/legr/bacodine/gcn3_archive.html

TITLE:   GCN CIRCULAR
NUMBER:  10273
SUBJECT: GRB 091208B: optical observations
DATE:    09/12/09 12:32:39 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen at iki.rssi.ru>

M.Andreev,  A.Sergeev, N.Parakhin, N.Karpov (Terskol Branch of  Institute of 
Astronomy), Yu. Kuznietsova (Main Astronomical Observatory NASU), V.Petkov 
(Baksan Neutrino Observatory INR) and A. Pozanenko (IKI) on behalf of larger 
GRB follow up collaboration report:

We observed the field of the Swift GRB 091208B (Pagani  et al. GCN  10256) 
with the Z-600 telescope of Mt.Terskol observatory in R-filter  on  Dec. 08 
starting at (UT) 15:40. In combined images we  detect the optical afterglow 
(Ugarte Postigo et al. GCN 10255, Pagani  et al. GCN  10256).

Preliminary photometry is based on the USNO-B1.0 reference star 
#1069-0020318  assuming  R2=17.47:

UT     Filter, Exposure, mag.  err.
(mid)             (s)

16:10  R  30x120  20.15  0.25
18:11  R  30x120  20.60  0.25
19:11  R  30x120  20.9    0.3
20:19  R  30x120  21.0    0.3

Combined image can be found in
http://grb.rssi.ru/GRB091208B/GRB091208B_Terskol600_R.jpg