[vsnet-grb-info 16847] GRB 150811A: SAO RAS optical observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  18128
SUBJECT: GRB 150811A: SAO RAS optical observations
DATE:    15/08/11 21:44:15 GMT
FROM:    Moskvitin Alexander at SAO RAS  <mosk at sao.ru>

A. S. Moskvitin (SAO RAS, Russia) report on behalf
of larger GRB follow-up collaboration:

The field of the GRB 150811A (Evans et al., GCNC #18119)
was observed with the Zeiss-1000, 1-m telescope of SAO RAS.
The observations started since 13.6 hours after the trigger.
6 x 300 sec frames in Rc filter were obtained under the
good weather conditions.

The OT (Butler et al., GCNC #18120; Zheng, Wang and Filippenko,
GCNC #18121; Kuin and Evans, GCNC #18122; Japelj, Guidorzi
and Kobayashi, GCNC #18123; Perley and Cenko, GCNC #18125)
is clearly detected in our stack image close to USNO-B1.0
star 0745-0762543. PSF photometry of the OT with DAOPHOT package
gives R = 20.74 +/- 0.12 (T_mid - T0 = 13.911 hours).

Photometry is based on the nearby USNO-B1 stars (R2 magnitudes).
The magnitude of the OT is not corrected for the Galactic extinction.