TITLE: GCN CIRCULAR NUMBER: 37142 SUBJECT: GRB 240811A: LCOGT Optical Upper Limit DATE: 24/08/11 22:45:39 GMT FROM: Robert Strausbaugh at Eastern Illinois University R. Strausbaugh (Eastern Illinois University), A. Cucchiara (NASA) report on behalf of a larger collaboration: We observed the Swift GRB 240811A (Beardmore et al., GCN 37136) field with the LCOGT 1-meter Sinistro instrument at the Teide Observatory, Tenerife site, on August 11, from 20:43 to 21:13 UT (corresponding to 6.60 to 7.10 hours after the GRB trigger time) with the sdss r and i filters. We performed a series of 3x300s exposures in each band. We do not detect an uncataloged source within the XRT error region in either band. This result is consistent with other optcal upper limits (Lipunov et al., GCN 37137; Du et al., GCN 37140). The following 5-sigma upper limits are calculated using the PanSTARRS catalog as reference: r > 22.6 i > 20.5 These magnitudes are not corrected for galactic extinction.