TITLE: GCN CIRCULAR NUMBER: 2778 SUBJECT: GRB041006, optical I observation DATE: 04/10/07 07:57:05 GMT FROM: Karl Glazebrook at Johns Hopkins E. Hoversten, K. Chiu, E. Nissen, C. Kelleman, K. Glazebrook (Johns Hopkins University, Baltimore, Maryland, USA) We have observed a 7x11 arcminute field centered on the afterglow of GRB041006 (GCN 2770) with the Morris Offit 20in Telescope of the Maryland Space Grant Consortium. The telescope is located in downtown Baltimore, Maryland and the observations were made with a student built CCD camera on the night of 7 October 2004. Images were obtained in I band at midpoint time 7 October 2004 UT 05:10:22, with a total exposure of 7200 seconds. We do not detect an optical counterpart, and place an preliminary upper limit on its magnitude at I=19.1 based on the faintest objects detectable in the field. Aperture photometry was made with APPHOT in a 9 arcsecond aperture, with relative photometry assuming I=16.1 (USNO-A2.0 red magnitude 16.2) for the reference star at 00:54:38.09 +01:12:59.9. Our image of the field may be viewed at http://www.pha.jhu.edu/~chiu/JHUgrb.ps More detailed analysis of data will follow. This message may be cited. The Maryland Space Grant Consortium Observatory is supported by NASA's National Space Grant College and Fellowship Program. Further information is available at http://henry.pha.jhu.edu/msgc/observatory.html