TITLE:   GCN CIRCULAR
NUMBER:  11340
SUBJECT: GRB 100906A: D50 optical detection
DATE:    10/10/13 16:00:35 GMT
FROM:    Jan Strobl at AI AS CR,Ondrejov  <jan@strobl.cz>

Jan Strobl (1,2), Martin Blazek (1,2), Martin Jelinek (3), Cyril Polasek
(1), Petr Kubanek (3,4), Martin Nekola (1), Matus Kocka (1) and
Rene Hudec (1,2)
(1. ASU AVCR Ondrejov, 2. FEL CVUT Praha, 3. IAA Granada, 4. IPL UV 
Valencia)

We report on the observation of the Swift GRB 100906A (Markwardt et al.,
GCN 11227) with the 0.5m telescope D50 in Ondrejov (Czech Republic),
starting at 21:17:37 UT, i.e. ~7.5h after the trigger. Eventually, six
hours of observational data were obtained, with the last image taken at
3:23:20 UT.

We clearly detect the afterglow reported by Ivanov et al. (GCN 11228),
and at the the beginning of our sequence (coadded first 7x 20s, exp.
mean time = 21:19 UT) we measure a magnitude 18.7 +- 0.2.

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