TITLE: GCN CIRCULAR NUMBER: 23088 SUBJECT: GRB 180805B: 1.5m OSN I-band observation DATE: 18/08/06 15:06:38 GMT FROM: Youdong HU at IAA-CSIC, UGR Y.-D. Hu, F.J. Aceituno, J. C. Tello and A.J. Castro-Tirado (IAA-CSIC Granada), on behalf of a larger collaboration, report: Following the detection of GRB 180805B (short burst with extended emission) by Swift (D'Avanzo et al. GCNC 23076, Sakamoto et al. GCNC 23082), optical images in the I-band were obtained at the 1.5m OSN telescope in Granada (Spain) starting at 03:08 (Aug 6), i.e. ~14 h postburst. No optical afterglow is detected in the co-added image (7 x 300s, mid time at 03:26 UT, 14.4 h after the trigger) within the enhanced Swift/XRT error box (Evans et al. GCNC 23077) down to I=21.0, which is in agreement with the non-detections reported by Lipunov et al. (GCNC 23085), Malesani et al. (GCNC 23086) and Ramsay et al.(GCNC 23087).