{
  "bibcode": "2010GCN.10662....1S",
  "body": "Jan Strobl (1), Martin Jelinek (2), Cyril Polasek (1), Petr Kubanek (2,3),\nMartin Nekola (1), Matus Kocka (1), Michal Jakubec (1) and Rene Hudec (1)\n(1. ASU AVCR Ondrejov, 2. IAA Granada, 3. GACE Valencia)\n\nWe observed the field of Swift trigger 420256 (Hoversten et al., GCNC \n10654) with the 0.5m telescope D50 in Ondrejov (Czech Republic), starting \nat 02:49:04 UT, i.e. 302s after the trigger. A sequence of 20s unfiltered \nimages was obtained. We coadded 15x20s exposure, obtaining an image with a \nlimitting magnitude Rc~18.0, with an effective exposure time 539s after \nthe trigger. We do not detect any new source in combined or single images.\n\nThis message can be cited.",
  "circularId": 10662,
  "createdOn": 1272053080000,
  "email": "jan@strobl.cz",
  "subject": "Swift Trigger 420256: D50 optical limits",
  "submitter": "Jan Strobl at AI AS CR,Ondrejov  <jan@strobl.cz>"
}