TITLE:   GCN CIRCULAR
NUMBER:  14475
SUBJECT: GRB 130427A: T100 observations
DATE:    13/04/27 22:39:19 GMT
FROM:    Eda Sonbas at NASA/GSFC  <edasonbas@gmail.com>

E. Sonbas (Adiyaman Univ.), T. Guver (Sabanci Univ.), E. Gogus (Sabanci
Univ.), H. Kirbiyik (TUG) report on behalf of a larger collaboration

We observed the field of Swift  GRB 130427A (Maselli et al. GCN#14448)
with  the  1.0 meter  T100  telescope  (TUBITAK National  Observatory,
Antalya - Turkey),  starting April, 27, 20:39:28 UT (~ 13 hours after
the trigger). Observations were carried out in the R filter under good
weather conditions. The afterglow is clearly  detected in 60 s R band
images at a position that is consistent with Elenin et al. GCN#14450

Using USNO-B1 star USNO-B1 1177-0254824  (RA=  11:32:31.23, Dec=
+27:42:23.02 ) in the field, the magnitudes of the OT were estimated as
follows;

t-t0 (hr)         exp.(s)      filt            mag             err (+/-)
12.850        60               R            16.2              0.05
12.871        60               R            16.6              0.03
12.874        60               R            16.3              0.03
12.877        60               R             16.5             0.01

Further observations using the same filter are ongoing.

We are grateful to the TUBITAK National Observatory staff for promptly
scheduling the observations and their technical support.