TITLE: GCN CIRCULAR NUMBER: 20183 SUBJECT: GRB 161117B: LCO optical observations DATE: 16/11/17 11:30:18 GMT FROM: Cristiano Guidorzi at Ferrara U,Italy C. Guidorzi (U. Ferrara), S. Kobayashi, I.A. Steele (LJMU), C.G. Mundell (U. Bath), A. Gomboc (U. Nova Gorica) on behalf of a large collaboration report: One of the LCO 1-m telescope units in Siding Springs began observing Swift GRB 161117B (Troja et al., GCN 20182) in the SDSS r filter on November 17, 10:28:49 UT (39 minutes since the GRB trigger time). We do not find any object within the XRT error circle down to the following limit: Mid time from GRB Exposure Filter Magnitude (min) (s) ---------------------------------------------------------- 45 5x120 SDSS-R > 21.2 ---------------------------------------------------------- Calibration is done against nearby USNOB-1 stars.