TITLE:   GCN CIRCULAR
NUMBER:  11234
SUBJECT: GRB 100901A: ISON-NM optical observations
DATE:    10/09/06 17:30:05 GMT
FROM:    Leonid Elenin at ISON  <l.elenin@gmail.com>

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

We continue observation of the Swift GRB 100814A (Immler et al. GCN Circ.
11159)
with 0.45-m telescope of ISON-NM observatory on Sep. 04 (UT) 09:04:35 -
10:06:19,
Sep. 05 (UT) 08:45:52 - 09:50:20 and Sep. 06 (UT) 09:36:57 - 11:14:22.

The afterglow (Immler et al., GCN 11159; Guidorzi et al., GCN 11160; Ivanov
et al.,
GCN 11161; Klunko et al., GCN 11162) is well detected on stacked images
for three epochs.

Preliminary photometry of unfiltered image against USNO-B1.0 1127-0027229,
assuming R=16.16  is following:

T-T0      filter   exposure   mag.  mag. error
--------------------------------------------------------------

2.8336    W      12x300   19.78    +/- 0.25

3.8206    W      12x300   20.38    +/- 0.20

4.8700    W      20x300   20.97    +/- 0.22

--------------------------------------------------------------

The images of GRB100901A is available at:

http://www.spaceobs.org/images/GRB1000901A-3epochs.jpg