TITLE: GCN CIRCULAR NUMBER: 8417 SUBJECT: GRB081024B: P200 Observations DATE: 08/10/27 05:23:08 GMT FROM: S. Bradley Cenko at Caltech S. B. Cenko (UC Berkeley) and M. M. Kasliwal (Caltech) report on behalf of a larger collaboration: We have imaged the error circle of the short duration GRB081024B (Omodei, GCN 8407; Connaughton and Briggs, GCN 8408) with the Large Format Camera mounted on the Palomar 200 inch Hale telescope. Images were taken in the Sloan r' and i' filters at a mean epoch of approximately Oct 26.1 (~ 30 hours after the burst). We detect several sources inside or near the potential X-ray afterglow (XRT Source 2; Guidorzi, Margutti, and Mao, GCN 8410; Guidorzi and Margutti, GCN 8416). Calibrating with respect to several nearby objects in the USNO-B1 catalog, we note the following positions and magnitudes for the four nearest sources: O1 - RA: 21:31:36.95 Dec: +21:16:35.4 (J2000.0) R = 20.6 mag O2 - RA: 21:31:37.63 Dec: +21:16:33.0 (J2000.0) R = 22.6 mag O3 - RA: 21:31:37.42 Dec: +21:16:36.4 (J2000.0) R = 23.4 mag O4 - RA: 21:31:37.32 Dec: +21:16:25.1 (J2000.0) R = 22.6 mag We estimate the astrometric precision for each source is 0.5" in each coordinate. The photometric precision for the above reported magnitudes is likely large (~ 0.3 mag) due to both zeropoint uncertainty and bandpass differences. The limiting magnitude of our co-added image is approximately R > 23.5 mag. We note that source O1 appears to be present in the DSS plates of this field. Additionally, source 02 is clearly extended. None of the objects show evidence for variability over the (limited) duration of our observations. An image of the field is posted at: http://www.srl.caltech.edu/~cenko/public/grb081024b.jpg Further observations to search for variability are encouraged.