GCN Circular 22068
C. Guidorzi (U. Ferrara), S. Kobayashi (LJMU), C.G. Mundell (U. Bath), A. Gomboc (U. Nova Gorica), I.A. Steele (LJMU) on behalf of a large collaboration report: We began observing Swift trigger 783893 (D'Avanzo et al. GCN 22067) on October 29, 06:48:16 UT (20 minutes since the trigger time) with one of the 1-m LCO McDonald telescopes in the SDSS-I filter. Within the Swift-BAT error circle a comparison with the SDSS field reveals no uncatalogued source down to i'~20 mag (SDSS calibrated) at a mid time of 26 minutes post trigger (5x120 s exposure).