TITLE: GCN CIRCULAR NUMBER: 22225 SUBJECT: GRB 171205A: iTelescope optical observations DATE: 17/12/10 12:51:52 GMT FROM: Veli-Pekka Hentunen at Taurus Hill Obs,A95 Veli-Pekka Hentunen and Markku Nissinen (Taurus Hill Observatory, Varkaus, Finland) report: We have observed GRB 171205A field at iTelescope observatory (Siding Spring, Australia) using T32 0.43-m f/6.8 astrograph. The optical counterpart was detected at the position RA 11:09:39.6 and DEC -12:35:18.5. The following magnitudes were obtained from the observations using NOMAD1 0774-0294483 (V=15.610) as a comparison star: Date Tmid(UT) Filter Exp. time Mag Mag.Err. 2017-12-09 17:00:25 unfiltered 10x120s 18.1 CV 0.5 2017-12-09 17:29:30 V 5x120s 17.4 0.6 --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus