2008A&A...492..603G

Some of the first results are reported from RISE - a new fast camera mounted on the Liverpool Telescope primarily designed to obtain high time-resolution light curves of transiting extrasolar planets for the purpose of transit timing. A full and partial transit of WASP-3 are presented, and a Markov-Chain Monte Carlo analysis is used to update the parameters from the discovery paper. This results in a planetary radius of 1.29^+0.05_–0.12R_J and therefore a density of 0.82^+0.14_–0.09ρ_J, consistent with previous results. The inclination is 85.06^+0.16_–0.15°, in agreement (but with a significant improvement in the precision) with the previously determined value. Central transit times are found to be consistent with the ephemeris given in the discovery paper; however, a new ephemeris calculated using the longer baseline results in T_c(0)=2454605.55915±0.00023 HJD and P=1.846835±0.000002 days.