GCN Circular 21134
C. Guidorzi (U. Ferrara), S. Kobayashi, I.A. Steele (LJMU), A. Gomboc (U. Nova Gorica), C.G. Mundell (U. Bath), A. Cucchiara, D. Morris, B. Gendre (U. of Virgin Islands) on behalf of a large collaboration report: We began observing Fermi-LAT GRB 170522A (Arimoto et al. GCN 21127; Stanbro et al. GCN 21126; Lipunov et al. GCN 21132) on May 23, 03:07 UT (11.4 hours since the GRB) with the 1-m LCO unit at the LCO McDonald observatory with the SDSS i filter. Within the LAT error circle we do not detect any uncatalogued source down to i~19 mag in a 3x120s stacked frame, as calibrated against nearby SDSS stars. Although all of the four X-ray sources reported by Swift-XRT (Mingo et al. GCN 21133) lie outside the LAT error circle, three of them (Sources 1, 2, 3) happen to lie within our field of view. We did not find uncatalogued counterparts in any of the corresponding error circles down to the same limit.