TITLE:   GCN CIRCULAR
NUMBER:  6806
SUBJECT: GRB 070920: TAROT Calern observatory optical observations
DATE:    07/09/20 05:04:31 GMT
FROM:    Alain Klotz at CESR-CNRS  <Alain.Klotz@free.fr>

Klotz, A. (CESR-OMP), Boer M. (OHP), Atteia J.L. (LATT-OMP) report:

We imaged the field of GRB 070920 detected by SWIFT
(trigger 291614) with the TAROT robotic telescope (D=25cm)
located at the Calern observatory, France.

The observations started 544.7s after the GRB trigger
(6.8s after the notice). The elevation of the field increased from
from 57 degrees above horizon and weather conditions
were excellents.

The date of trigger : t0 = 2007-09-20T04:00:14.112

The first image is 90.0s exposure in tracking mode:
t0+544.7s to t0+634.7s : R > 18.2

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

N.B. Galactic coordinates are lon=142.6283 lat=+25.1560
and the galactic extinction in R band is 0.3 magnitudes
estimated from D. Schlegel et al. 1998ApJ...500..525S.

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