TITLE: GCN CIRCULAR NUMBER: 14394 SUBJECT: GRB 130418A: T18 and T21 optical observations DATE: 13/04/19 15:49:18 GMT FROM: Veli-Pekka Hentunen at Taurus Hill Obs,A95 Veli-Pekka Hentunen, Markku Nissinen and Tuomo Salmi (Taurus Hill Observatory, Varkaus, Finland) report: We have detected GRB 130418A optical afterglow at iTelescope observatories T18 and T21. Four unfiltered and three photometric V filter images with 300 sec exposure time were made at T18 (AstroCamp Observatory, Nerpio, Spain) 0.32-m/8.0 Astorgraph and KAF-6303E CCD. Two unfiltered and four photometric V filter images with 600 sec exposure time were made at T21 (Mayhill, New Mexico) 0.43-m/6.8 astrograph and FLI ProLine PL6303E CCD. The afterglow was detected at following position RA 09:56:08.94 and DEC +13:40:02.9. The following magnitudes were obtained from the observations using NOMAD1 1036-0179295 (V= 14.750, R = 14.910) as the comparison: Tmid(sec) +T0 Filter Exp time Mag Mag err. 3119 unfiltered 300 16.200CR 0.026 3406 unfiltered 300 16.305CR 0.027 3758 unfiltered 300 16.381CR 0.027 4118 unfiltered 300 16.496CR 0.030 4835 V 300 16.895V 0.082 5195 V 300 16.979V 0.081 5546 V 300 16.983V 0.085 6432 V 600 17.320V 0.075 7093 V 600 17.342V 0.077 8026 unfiltered 600 17.328CR 0.044 8691 unfiltered 600 17.519CR 0.053 9742 V 600 17.775V 0.123 11059 V 600 17.752V 0.193