[vsnet-grb-info 13174] GRB 130427A: Challis Observatory optical observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  14511
SUBJECT: GRB 130427A: Challis Observatory optical observations
DATE:    13/04/30 03:59:05 GMT
FROM:    Jay Norris at U. of Denver  <jnorris at custertel.net>

Jay Norris, Daryl Macomb (Boise State U.) report:

We observed GRB 130427A with the Challis Observatory's 0.4-m telescope
(114.33 deg W, 44.5 deg N, 2165 m elevation) on April 29, 05:58 to 06:22 UT.
Using seventeen 10-second frames in the R filter acquired in a clear sky,
centered at ~ 06:06 UT, 22.3 hours after the Swift/BAT trigger (GCN 14448),
we clearly detected the optical afterglow.

Comparison with six stars in the field of view (R = 15.5 to 16.8 mag)
yielded an estimate of R = 17.6 mag for the afterglow with uncertainty
of ~ 0.15 mag.  Further observations were interrupted by clouds.