TITLE: GCN CIRCULAR NUMBER: 7595 SUBJECT: GRB 080413: TAROT Calern observatory optical observations DATE: 08/04/13 03:54:16 GMT FROM: Alain Klotz at CESR-CNRS Klotz, A. (CESR-OMP), Boer M. (OHP), Atteia J.L. (LATT-OMP) report: We imaged the field of GRB 080413 detected by SWIFT (trigger 309096) with the TAROT robotic telescope (D=25cm) located at the Calern observatory, France. The observations started 21.8s after the GRB trigger (8.3s after the notice). The elevation of the field increased from from 11 degrees above horizon and weather conditions were poor at the beginning of observations. The first image showing stars started 480s after the trigger. We detected the candidate couterpart mentioned by Rykoff et al. (GCNC 7593) at the following position (+/- 2 arcsec): RA(J2000.0) = 19h 09m 11.85s DEC(J2000.0) -27d 40' 43.0" Unfiltered magnitudes are: t0+480s to t0+570s : R > 12.5 t0+1174s to t0+1263s : R = 15.0 +/- 0.2 t0+1470s to t0+1650s : R = 15.3 +/- 0.2 t0+2035s to t0+2215s : R = 15.5 +/- 0.2 Magnitudes were estimated with the nearby USNO-B1 stars and are not corrected for galactic dust extinction. N.B. Galactic coordinates are lon= 9.5236 lat=-15.8249 and the galactic extinction in R band is 2.4 magnitudes estimated from D. Schlegel et al. 1998ApJ...500..525S. This message may be cited.