TITLE: GCN CIRCULAR NUMBER: 30275 SUBJECT: GRB 210619B: CAHA 2.2m photometric monitoring DATE: 21/06/20 15:53:18 GMT FROM: Alexander Kann at IAA-CSIC D. A. Kann (HETH/IAA-CSIC), A. de Ugarte Postigo (HETH/IAA-CSIC, DARK/NBI), M. Blazek, C. Thoene, J.F. Agui Fernandez, Ginger (all HETH/IAA-CSIC), and J. I. Vico Linares (CAHA) report: We observed the afterglow of GRB 210619B (Swift detection: D'Avanzo et al., GCN 30261; GECAM detection: Zhao et al., GCN 30264; Fermi-LAT detection: Axelsson et al., GCN 30270; Afterglow detections: Lipunov et al., GCN 30259; D'Avanzo et al., GCN 30261; Lipunov et al., GCN 30262; Jelinek et al., GCN 30263; Kong, GCN 30265; Pellegrin et al., GCN 30268; Perley, GCN 30271; Zheng & Filippenko, GCN 30273; Blazek et al., GCN 30274; Redshift: de Ugarte Postigo, GCN 30272) with CAFOS mounted at the 2.2m Calar Alto telescope (Almeria, Spain). After a weather-induced delay, we obtained 80 x 60 s images in Ic. The afterglow is clearly detected in each image. The sequence starts at 01:23 UT and ends at 03:43 UT on 2021-06-20 (0.05836 to 0.15479 d after burst trigger). Comparing to a single star with a magnitude derived from PanSTARRS and transformed following Lupton (2005), we find the afterglow decays from Ic (AB) = 16.75 +/- 0.05 mag to Ic (AB) = 17.45 +/- 0.05 mag. Further observations are planned.