TITLE: GCN CIRCULAR NUMBER: 18539 SUBJECT: GRB 151027A: optical follow-up observations DATE: 15/10/31 06:39:13 GMT FROM: Patrick Wiggins at Wiggins Obs P. Wiggins reports: Observed GRB 151027A with a .35-meter optical telescope at my home observatory, IAU 718, on 2015 October 27 from 0433 to 0732 UTC using a clear filter and obtained the following: GRB Countpart: 18h 09m 56.71s +61d 21m 12.78s Reference One: 18h 10m 05.68s +61d 23m 14.97s Reference Two: 18h 09m 51.53s +61d 22m 48.87s Julian Date Date Ref. C Ref. K Var. V C-K Differential Mid Exposure yyyy-mm-dd.ddddd Raw Mag. Raw Mag. Raw Mag. Differ. Mag. -------------- ---------------- --------- --------- --------- --------- ------------ 2457322.689715 2015 10 27.18972 -2.937 -3.111 -1.085 0.174 15.051 2457322.692866 2015 10 27.19287 -2.433 -2.622 -1.355 0.190 14.278 2457322.700101 2015 10 27.20010 -2.732 -2.925 -1.433 0.192 14.499 2457322.703174 2015 10 27.20317 -2.921 -3.112 -1.605 0.191 14.516 2457322.724392 2015 10 27.22439 -2.909 -3.088 -1.391 0.180 14.718 2457322.758285 2015 10 27.25829 -2.949 -3.142 -1.151 0.193 14.998 2457322.786495 2015 10 27.28649 -2.906 -3.085 -0.916 0.180 15.189 2457322.801286 2015 10 27.30129 -2.901 -3.108 -0.722 0.207 15.379 2457322.814370 2015 10 27.31437 -2.879 -3.079 -0.406 0.201 15.673 END