TITLE: GCN GRB OBSERVATION REPORT NUMBER: 1591 SUBJECT: GRB021004, Optical Observations DATE: 02/10/06 17:59:20 GMT FROM: Arne A. Henden at USNO/USRA Arto Oksanen (Nyrola), Mika Aho (Nyrola), Kevin Rivich (Ft. Bend), Kim Rivich (Ft. Bend), Doug West (West Skies), and Doug Durig (Cordell-Lorenz) report on behalf of the AAVSO International GRB team: We have observed the optical afterglow candidate (Fox et al., GCN 1564) for GRB021004 (Shirasaki et al., GCN 1565; Doty et al., GCN 1568) from multiple observatories. The preliminary photometric reductions are given below; these measures will be improved, but indicate the datasets that are currently available: Date UT sec x n fil Site mag 021004 19:53 60x22 Rc Nyrola 0.4m 17.90 021004 21:24 120x10 Rc Nyrola 0.4m 17.96 021004 21:48 120x11 Rc Nyrola 0.4m 18.22 021004 22:25 240x9 Rc Nyrola 0.4m 18.37 021004 23:26 240x10 Rc Nyrola 0.4m 18.41 021004 00:13 240x10 V Nyrola 0.4m 19.25 021005 01:04 240x10 Rc Nyrola 0.4m 18.83 021005 01:28 60x12 CR West 0.2m 19.0 021005 02:08 300x3 CR Cordell 0.3m 19.0 021005 04:43 20x60 Rc Ft. Bend 0.9m 19.2 Where CR indicates unfiltered measures, zeropointed onto the Rc system. Further observations are in progress. This report can be cited.