TITLE:   GCN CIRCULAR
NUMBER:  26561
SUBJECT: GRB 191221B: Zadko observatory - Gingin optical observations
DATE:    19/12/22 19:43:01 GMT
FROM:    Bruce Gendre at UVI  <bruce.gendre@gmail.com>

B. Gendre (OzGrav-UWA), H. Crisp (OzGrav-UWA), J. Moore (OzGrav-UWA), 
D. Coward (OzGrav-UWA), A. Klotz (IRAP-CNRS-OMP), P. Thierry (Aragne 
Observatory), A. Burrell (OzGrav-UWA), J. Zadko (Claire Energy), 
M. Boer, (UNS-CNRS-OCA)
report:

We imaged the field of GRB 191221B detected by Swift (trigger 945521, 
Laha et al. GCN 26534) with the Zadko robotic telescope (D=100cm)
located at the Zadko observatory - Gingin, Australia.

The observations started 19 hours after the GRB trigger. The elevation 
of the field was at 32 degrees above horizon and weather conditions
were good. We performed 6 long exposures of 180s in Clear filter.

We detected the candidate couterpart mentioned by Lipunov et al. (GCNC 
26537) in each of the images.

OT was R~17.6+/-0.2 at that time. Further analysis and observations are 
ongoing.

Magnitudes were estimated with the nearby USNO-B1 stars
and are not corrected for galactic dust extinction.

This message may be cited.