GCN Circular 23687
A. de Ugarte Postigo (HETH/IAA-CSIC and DARK/NBI), D. A. Kann, L. Izzo, C. C. Thoene, M. Blazek, K. Bensch (all HETH/IAA-CSIC), and F. Aceituno (IAA-CSIC) report: We observed the optical afterglow of GRB 190114A (Siegel & LaPorte, GCN #23678), detected by Swift (LaPorte et al., GCN #23677), with the T150 telescope of the Sierra Nevada Observatory (OSN). We obtained 5 x 360 s images in the Ic band at 16.98 hours after the GRB. The afterglow is well-detected in each single image. Days Ic mag error 0.7075 20.41 0.10 Magnitudes are given in the AB system. They were measured vs. four Pan-STARRS comparison stars, using the transformation equations of Lupton (2005), and transformed back into AB mags.