TITLE: GCN CIRCULAR NUMBER: 6284 SUBJECT: GRB 070412: Optical observations at Crni Vrh DATE: 07/04/12 09:40:32 GMT FROM: Herman Mikuz at OCV H. Mikuz, J. Skvarc and B. Dintinjana on behalf of PIKA observing program at Crni Vrh Observatory: We observed a 42'x42' field centered on Swift position at ra=12:06:01 dec=+40:06:03 (J2000), using 60 cm Cichocki robotic telescope at Crni Vrh Observatory, Slovenia. There is no obvious source down to R magnitude 20.7 +/-0.1 inside the error box 3x3 arc minutes on 90 s R filter exposure, starting at 2007 Apr. 12 01:39:03 UT (46 seconds after reception of the alert) and 5 subsequent images of the same duration. Magnitudes were calibrated against the USNO-B1 catalogue. In particular we also do not observe any source to this limiting magnitude at the coordinates reported by NOT (Malesani and Uthars, GCN 6276) or Jelinek et al. (GCN 6279).