[AAVSO-HEN] GRB 090817: optical upper limit

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The following is a GCN Circular circulated via the AAVSO network.
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TITLE:   GCN CIRCULAR
NUMBER:  9826
SUBJECT: GRB 090817: optical upper limit
DATE:    09/08/18 12:02:36 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen at iki.rssi.ru>

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

We observed a field of the INTEGRAL GRB 090817 (Beckmann et al., GCN 9815) 
with Shajn telescope of  CrAO starting on Aug. 17 (UT) 01:07, i.e. ~17 
minutes after burst onset. A series of 37 images of 60 s exposure was 
obtained in R filter. Within XRT error circle of  the afterglow (Evans et 
al., GCN 9819, GCN 9825) we do not detect any new object. The quoted 
USNO-B1.0 star USNO-B1.0 1341-0096763 (Evans et al., GCN 9819) does not 
change its brightness within ~0.08 m during our observations. An upper limit 
of a single frame of 60 s exposure is R~21.5 m. Data reduction is 
continuing.