TITLE:   GCN CIRCULAR
NUMBER:  11012
SUBJECT: GRB 100728B: optical detection
DATE:    10/07/28 12:13:28 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

L. Elenin (ISON), I. Molotov (ISON), A. Pozanenko (IKI)  report on behalf of 
larger GRB  follow-up collaboration:

We observed the field of the Swift GRB 100728B (Page et al. GCN  11009) with 
0.45-m astrograph f/2.8 Ïf ISON-NM observatory (32d 54' 11.64'',  105d 31' 
42. 34'' ) starting July 28 (UT) 10:56:08, i.e. 24 minutes after burst 
onset.  A few unfiltered 300s exposures were taken before down. In a first 
exposures we clearly detect the afterglow at the position (J2000) RA= 02 56 
13.48 Dec= +00 16 51.4 which  coincides with early afterglow detection 
(Perley et al. GCN  11007; Page et al. GCN  11009).

A preliminary photometry of unfiltered exposures against USNO-B1.0 field 
stars (R-filter) at 29.3 minutes after burst is 19m.