GCN Circular 26526
N. P. M. Kuin (UCL-MSSL) and S. L. Laha (GSFC/UMBC/CRESST) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 191220A 138 s after the BAT trigger (Laha et al., GCN Circ. 26516). No optical afterglow consistent with the XRT position (Laha et al. GCN Circ. 26516) is detected in the initial UVOT exposures. Preliminary 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first finding chart (FC) exposure and subsequent exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag u_FC 138 387 246 >19.8 u 138 6726 1061 >20.0 w1 446 6521 687 >19.6 m2 420 6316 687 >19.9 w2 396 6766 719 >21.1 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.14 in the direction of the burst (Schlegel et al. 1998).