TITLE: GCN CIRCULAR NUMBER: 10183 SUBJECT: GRB 091117: 2nd epoch of Magellan optical observations DATE: 09/11/20 06:00:05 GMT FROM: Edo Berger at Harvard E. Berger (Harvard) and I. Momcheva (OCIW) report: "We obtained a second set of optical r-band observations of the BAT error circle of GRB 091117 (GCN #10171) with IMACS on the Magellan/Baade 6.5-m telescope starting on 2009 Nov 20.03 UT. A comparison to our first epoch of Magellan observations (GCN #10174) reveals no variable sources within the BAT error circle or in coincidence with the two XRT sources (GCNs #10173,10177,10181) to a limit of r~24 mag. The point source identified as an HII region (GCN #10176) has not varied in brightness. Further analysis is in progress."