TITLE:   GCN CIRCULAR
NUMBER:  13200
SUBJECT: GRB 120402A: optical upper limit
DATE:    12/04/03 18:48:49 GMT
FROM:    Alina Volnova at SAI MSU  <alinusss@gmail.com>

A. Volnova (SAI MSU), E. Litvinenko (UBAI), I. Molotov (KIAM), A.
Pozanenko (IKI) on behalf of  larger GRB follow up collaboration
report:

We observed the field of the possible GRB 120402A (Swift
trigger=519207; Barthelmy et al.,  GCN 13190) with ORI-40 telescope of
Kitab ISON observatory on Apr. 02 starting  (UT) 22:55:14, i.e. ~6 min
after burst trigger. We obtained several  unfiltered images with
exposure of 60 seconds. Within BAT error circle of 3 arcmin, radius
(Barthelmy et al.,  GCN 13190) we do not detect apparently new source
in comparison with DSS2-red.  The  photometry is based on  USNO-B1.0
reference star 1092-0548647  (20:57:27.42 +19:17:47.2) assuming R =
14.41.

Tstart UT,   T0+,        Filter, Exposure, OT,  UL (3 sigma)
               (mid, d)               (s)

22:55:14    0.01449    none   2800      n/d     19.8