GCN Circular 6500
John French, Gary Melady (University College Dublin), Petr Kubanek, Martin Jelinek (IAA CSIC Granada, Spain) on behalf of the Watcher collaboration report: The Watcher 40cm robotic telescope, located at Boyden Observatory, South Africa, began imaging the field of GRB 070610 (Pagani et al., GCN 6489) at 20:53:19 UT, 53s after the Swift trigger (23s after receipt of the GCN notice). Our first 10s unfiltered exposure shows no new source in the XRT error box (Pagani et al., GCN 6490) down to an R-band limiting magnitude of approx. 15.1 (in comparison to USNO-B1). A series of unfiltered 10s exposures were combined to create a 548s exposure, with a mean time of 20:57:48 UT (269s after the trigger). No new source was detected in this image down to an R-band limiting magnitude of approx. 17.5. This message may be cited.