[vsnet-grb-info 17250] GRB 151118A: Optical observations from OSN

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  18612
SUBJECT: GRB 151118A: Optical observations from OSN
DATE:    15/11/18 04:36:51 GMT
FROM:    Antonio de Ugarte Postigo at IAA-CSIC  <deugarte at iaa.es>

A. de Ugarte Postigo (IAA-CSIC, DARK/NBI), A. Sota (IAA-CSIC), 
and C. Thoene (IAA-CSIC) report:

We observed the field of GRB 151118A (Amaral-Rogers et al. GCN 18611) 
with the 1.5 m OSN telescope in Granada (Spain), starting at 03:17:55 UT 
(11.42 min after the GRB onset). Observations consisted of 7x300 s 
exposures in I-band. No new source is detected within the XRT error box. 
The 3-sigma limiting magnitudes of the individual exposures, and the combined
frames are I(Vega) = 21.5 mag, and I(Vega) = 22.5 mag, respectively. The mean
time of the combined exposure is 03:37:49 (31.32 min after the burst). Photometry
was obtained by comparison with stars from the USNO-B1.0 catalogue.