TITLE: GCN CIRCULAR NUMBER: 16722 SUBJECT: Fermi trigg_num 430148973: OSN I-band observations DATE: 14/08/19 21:21:44 GMT FROM: Javier Gorosabel at IAA-CSIC F. Espartero (IAA-CSIC), F.J. Aceituno (OSN/IAA-CSIC), J. Gorosabel (IAA-CSIC/UPV-EHU) and A.J. Castro-Tirado (IAA-CSIC/UMA), report on behalf of a larger collaboration: We observed the field of the optical candidate reported for Fermi trigger #430148973 (Lipunov et al. GCN 16720) with the 1.5m OSN telescope at Observatorio de Sierra Nevada (Spain). The observations were carried out in the I-band starting at 20:27:42 UT (6.6 hours post trigger). We do not detect any source brighter than I=20.2 (Vega) consistent with the candidate position.