Jan Strobl (1), Martin Jelinek (2), Cyril Polasek (1), Petr Kubanek (2,3),
Martin Nekola (1), Matus Kocka (1), Michal Jakubec (1) and Rene Hudec (1)
(1. ASU AVCR Ondrejov, 2. IAA Granada, 3. GACE Valencia)
We observed the field of Swift trigger 420256 (Hoversten et al., GCNC
10654) with the 0.5m telescope D50 in Ondrejov (Czech Republic), starting
at 02:49:04 UT, i.e. 302s after the trigger. A sequence of 20s unfiltered
images was obtained. We coadded 15x20s exposure, obtaining an image with a
limitting magnitude Rc~18.0, with an effective exposure time 539s after
the trigger. We do not detect any new source in combined or single images.
This message can be cited.