GCN Circular 14394

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