TITLE: GCN CIRCULAR NUMBER: 11174 SUBJECT: GRB 100901A: SARA-N observations DATE: 10/09/02 12:28:03 GMT FROM: Adria C. Updike at Clemson U Adria C. Updike, Dieter H. Hartmann (Clemson University) and William Keel, Erin Darnell (U Alabama) report: We observed the field of GRB 100901A (Immler et al., GCN 11159) with the 0.9m SARA-North telescope located at KPNO beginning 18 hours and 45 minutes after the trigger under good conditions. In 240s exposures, we clearly detect the afterglow in all images. Filter Mag Mag error UT Start --------------------------------------- B 18.7 0.1 08:20 V 18.2 0.1 08:24 R 18.0 0.1 08:28 I 17.9 0.1 08:32 Magnitudes are reported relative to the USNO B1.0 and NOMAD catalogs field stars. Observations in all bands continued for 4 hours. Further observations are planned.