TITLE: GCN CIRCULAR NUMBER: 25940 SUBJECT: GRB 191001B: Optical Upper Limits with LCO DATE: 19/10/03 18:30:36 GMT FROM: Robert Strausbaugh at U. of the Virgin Islands R. Strausbaugh (U. of the Virgin Islands), A. Cucchiara (U. of the Virgin Islands/College of Marin) report on behalf of a larger collaboration: We observed Swift GRB 191001B (Barthelmy et al., GCN 25902) with the LCO 1-m Sinistro instrument on October 2, from 01:23 to 01:47 UT (corresponding to 5.73 to 6.2 hours from the GRB trigger time) with the SDSS r’ and i’ filters. We performed a series of 5x120s exposures in each band. We do not detect any fading sources over the course of our observations in a 26.5' x 26.5' field of view centered around the Swift coordinates (Barthelmy et al., GCN 25902). Using the USNO-B.1 catalog as reference, we obtain the following 3-sigma upper limits: r > 18.82 i > 16.98 These observations were possible thanks to the USVI NASA-EPSCoR Research Infrastructure Development (RID) grant NNX16AL44A.