TITLE: GCN CIRCULAR NUMBER: 22941 SUBJECT: GRB 180705A: OSN observations DATE: 18/07/11 19:25:41 GMT FROM: Alexander Kann at IAA-CSIC D. A. Kann, L. Izzo (both HETH/IAA-CSIC), and A. Sota (IAA/CSIC) report on behalf of HETH: We observed the field of GRB 180705A (Stamatikos et al., GCN #22902) with the 1.5-m OSN telescope in Granada, Spain. We obtained 20 x 300 s images in the Ic band centered at 0.262416 days (6.3 hrs) after the GRB. At the XRT position of the GRB (Goad et al., GCN #22906), there is a possible faint source, formally detected at Ic (Vega) = 23.6 +/- 0.2 mag. We note, however, that the background of the image is structured because of the proximity of the bright star HD 123921 (V ~ 9 mag), therefore the detection may be spurious. The formal 3 sigma upper limit is Ic > 24 mag, also possibly overestimated. Even if the source we detect is not real, any afterglow of this GRB is clearly very faint, in agreement with other non-detection reports (Lipunov et al., GCN #22904, Watson et al., GCN #22911, Breeveld et al., GCN #22912, Mazaeva et al., GCN #22913, Bikmaev et al., GCN #22929). The field was calibrated against SDSS secondary standard stars using the transformation of Lupton (2005).