TITLE: GCN CIRCULAR NUMBER: 22657 SUBJECT: GRB 180418A: 1.5m OSN optical observations DATE: 18/04/18 20:57:12 GMT FROM: Alberto Castro-Tirado at Inst.de Astro. de Andalucia A. Sota, Y. Hu, J. C. Tello, I. Carrasco and A. J. Castro-Tirado (IAA-CSIC), on behalf of a larger collaboration, report: "Following the detection of GRB 180418A with the Neil Gehrels Swift Observatory (D'Elia et al. GCNC 22646), I-band observations at the 1.5m telescope at Observatorio de Sierra Nevada (Granada, Spain) have been gathered on Apr 18 starting at 19:49 UT (13 hr post burst). At the position of the optical afterglow (Zheng and Filippenko, GCNC 22647; Guidorzi et al., GCNC 22648; Troja et al., GCNC 22652), no counterpart is detected down to I = 21.0 in the coadded image (5x300s)."