TITLE: GCN CIRCULAR NUMBER: 21609 SUBJECT: LIGO/Virgo G298048: Etelman Observatory observation of the potential LIGO EM counterpart SSS17a DATE: 17/08/20 05:27:49 GMT FROM: Bruce Gendre at U of Virgin Islands B. Gendre (UVI), A. Cucchiara (UVI), D. Morris (UVI), N. Orange (OrangeWave Innovative Science, LLC), D. Drost (UVI), T. Giblin (USAF Academy), J. Hakkila (College of Charleston), A. Klotz (IRAP), J. Neff (NSF), D. Smith (UVI), J. Staff (UVI), P. Thierry (Auragne Observatory), R. Watlington (UVI), on behalf of the FIGARO collaboration report: We observed the field of SSS17a (Coulter et al., GCN 21529; Allam et al., GCN 21530; Yang et al., GCN 21531), the potential counterpart of the LIGO/Virgo event G298048 (GCN 21509), with the 0.5m Virgin Island Robotic Telescope (VIRT) on August the 19th, starting at 23:19 UT. We performed a series of exposures in the R and Clear filters, with an elevation decreasing from 40 degrees. The weather conditions were good, with a mean seeing of 2-3 arcsec. We detect an excess at the position of the potential counterpart in C filter at 23:54 UT. Strong contamination from the nearby galaxy prevents a precise brightness estimate without galaxy substraction. Further analysis is in progress. The VIRT is still in its commissioning phase. This message can be cited.