TITLE: GCN CIRCULAR NUMBER: 21269 SUBJECT: GRB 170626A: Afterglow detection from 1.5m OSN DATE: 17/06/26 22:27:03 GMT FROM: Antonio de Ugarte Postigo at IAA-CSIC A. de Ugarte Postigo (IAA-CSIC, DARK/NBI), and F. Aceituno, D.A. Kann, L. Izzo, C. Thoene (IAA-CSIC) report on behalf of a larger collaboration: We observed the field of GRB 170626A (Marshal et al. GCN 21264) with the 1.5m OSN telescope in Sierra Nevada Observatory (Granada, Spain). Observation consisted of a series of 240 s R-band exposures, starting at 20:56:49 UT (11.32 hr after the burst). The afterglow is well detected at a position consistent with the one reported by Moskvitin et al. (GCN 21268), (J2000, +/-0.5”): R.A.: 11:01:34.09 Dec.: +56:28:35.4 In the combination of the first 12x240s exposures we measure a magnitude of R(AB) = 20.6+/- 0.2 as compared to SDSS stars.