GCN Circular 23963
M. Blazek, L. Izzo. D. A. Kann (all HETH/IAA-CSIC), A. de Ugarte-Postigo (HETH/IAA-CSIC, DARK/NBI) and C. C. Thoene (HETH/IAA-CSIC) report: We observed the Swift GRB 190311A (Troja et al, GCN 23946) with the 2-m Liverpool Telescope located in La Palma, Spain. The observation started at 02:19:56 UT on March 12, 2019 (t-t0 = 11.94 hours). We obtained 5x60 seconds exposures each in g', r', and i'. We clearly detected the optical afterglow inside the Swift-XRT error circle given of Goad et al. (GCN 23950). We measure the following magnitudes g' = 22.18 +- 0.24 mag, r' = 21.70 +- 0.13 mag, i' = 21.54 +- 0.18 mag. Magnitudes were derived against 9 nearby stars from the SDSS catalogue and are in the AB system.