TITLE: GCN CIRCULAR NUMBER: 21644 SUBJECT: LIGO/Virgo G298048: observations of optical counterpart candidate with CHILESCOPE observatory DATE: 17/08/22 15:23:04 GMT FROM: Alexei Pozanenko at IKI,Moscow A. Pozanenko (IKI), A. Volnova (IKI), E. Mazaeva (IKI), P. Minaev (IKI), M. Krugov (AFIF) report on behalf of IKI-GW follow-up collaboration: We continue observation of the possible counterpart SSS17a/DLT17ck (Coulter et al. GCN 21529; Yang et al., GCN 21531) of LIGO/Virgo trigger G298048 (GCNs 21509, 21513) with RC-1000 telescope of CHILESCOPE observatory. The observations carried out in clear filter starting on Aug. 21 (UT) 23:32:09. Preliminary Photometry of the transient SSS17a/DLT17ck is following Date UT start MJD Filter OT Err UpLim (3 sigma) 2017-08-21 23:32:09 57987.00386 CR 18.8 0.2 22.2 The photometry is based on several nearby USNO-B1.0 stars (R2). The photometry is still preliminary and required careful estimation of NGC4339 influence. We are grateful for the team of remote controlled CHILESCOPE observatory (www.chilescope.com) for observations.