TITLE: GCN CIRCULAR NUMBER: 7526 SUBJECT: GRB080328: Faulkes Telescope North observations DATE: 08/03/28 09:39:11 GMT FROM: Cristiano Guidorzi at INAF-OAB C. Guidorzi (INAF-OAB),, A. Gomboc (U. Ljubljana), D. Bersier, C.G. Mundell, I.A. Steele, R.J. Smith, D. Carter, S. Kobayashi, M. Bode (Liverpool JMU), P. O'Brien, N. Bannister, N. Tanvir (U. Leicester) report: The 2-m Faulkes North Telescope (Hawaii) automatically reacted to the Swift burst GRB080328 (trigger=307931, Perri et al. GCN 7525). Observations started about 167 s after the trigger time. We confirm the detection of the optical counterpart by UVOT. From the first 3x10 s exposure frames in R, we estimate a temporal decay index between 167 and 240 s after the trigger time of alpha = 1.4 +/- 0.2. Filter Tstart(s) Exposure(s) Mag ----------------------------------------------- R 167 10 16.96 +/- 0.02 R 198 10 17.26 +/- 0.02 R 230 10 17.44 +/- 0.02 ----------------------------------------------- Magnitudes are calibrated with respect to USNOB1 R2 in the R filter. A systematic error on absolute magnitudes of ~0.3 must be included.