TITLE: GCN CIRCULAR NUMBER: 8755 SUBJECT: GRB 081230: Swift/UVOT Detection of an Optical Afterglow DATE: 08/12/30 21:21:51 GMT FROM: Stephen Holland at USRA/NASA/GSFC/SSC S. T. Holland (CRESST/GSFC/USRA), P. J. Brown (PSU), and V. La Parola (INAF-IASFPA) report on the behalf of the Swift UVOT team: The Swift/UVOT detects a faint source in the XRT error circle for GRB 081230 (La Parola, et al. 2008, GCN Circ. 8753). The source has a preliminary position of RA (J2000) 02:29:19.48 = 37.33117 (deg) Dec (J2000) -25:08:48.5 = -25.14682 (deg) and a preliminary u-band magnitude of u = 20.6 +/- 0.3 mag in a 250 s exposure starting 131 s after the BAT trigger. The quoted magnitude has not been corrected for the expected Galactic extinction along the line of sight corresponding to a reddening of E_{B-V} = 0.01 mag (Schlegel, et al., 1998, ApJS, 500, 525). The photometry is on the UVOT flight system described in Poole et al. (2008, MNRAS, 383, 627).