TITLE: GCN CIRCULAR NUMBER: 27176 SUBJECT: GRB 200224A: BOOTES-1 and 1.5m OSN optical observations DATE: 20/02/24 06:37:24 GMT FROM: Alberto J. Castro-Tirado at IAA-CSIC A. Sota, E. Fernandez-Garcia, Y.-D. Hu and A. J. Castro-Tirado (IAA-CSIC), A. Castellon, I. Carrasco-Garcia and C. Perez del Pulgar (UMA), on behalf of a larger collaboration, report: Following the detection of GRB 200224A by Swift (Ukwatta  et al., GCNC 27173), the 0.3cm robotic telescope at the BOOTES-1 astronomical station at INTA-CEDEA in Huelva (Spain) started gathering images at 03:26:27 UT, 40s after the alert and 118s after the onset of the burst. No optical transient is detected in the single images with a limiting magnitude of 14 (consistent with the MASTER upper limit, Lipunov et al., GCNC 27172). Further data reduction is ongoing. Deeper exposures were obtained with the 1.5m telescope at Observatorio de Sierra Nevada starting at 05:35 UT (i.e. 2.1 h post burst).  We find an optical source consistent with the Swift/XRT position,  at coordinates (RA & Dec, J2000)  = 16:35:04.11 +41:36:42 (+/- 1”). The preliminary magnitude is R = 22. Further observations are planned to confirm whether this is the optical afterglow to GRB 200224A. This message can be quoted. [GCN OPS NOTE(24feb20): This is the fifth Circular in the sequence of 8 circulars which were all labeled A because of the sequence assigner being offline. This circular was correctly labelled A.]