TITLE:   GCN CIRCULAR
NUMBER:  17560
SUBJECT: GRB150309A: Optical observations at Crni Vrh
DATE:    15/03/10 14:27:29 GMT
FROM:    Herman Mikuz at OCV  <herman.mikuz@fmf.uni-lj.si>

B. Dintinjana, S. Maticic and H. Mikuz on behalf of PIKA observing 
program at Crni
Vrh Observatory.

We observed the field of GRB 150309A (Cummings et al., GCN 17553) from 
Crni Vrh Observatory with a 60 cm robotic telescope and clear filter. 
Twenty six consecutive exposures of 60 second duration were taken in 
moonlight conditions. First exposure started at 2015-03-09 23:05:34 UT, 
68 seconds after the SWIFT trigger.

No optical candidate was detected within the uncertainty radius on 
single exposures, having limiting magnitude 19.2, calibrated against the 
nerby USNO-B R2 magnitude stars. Also we found no optical candidate on 
26 sumed unfiltered images with total exposure of 1560 seconds and 
limiting magnitude 20.8 (calibrated against the nerby USNO-B R2 
magnitude stars).