[AAVSO-HEN] GRB041006: Liverpool Telescope optical observations

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TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  2790
SUBJECT: GRB041006: Liverpool Telescope optical observations
DATE:    04/10/08 22:10:58 GMT
FROM:    Alessandro Monfardini at JMU/Liverpool Robotic Tele  <am at astro.livjm.ac.uk>

A. Monfardini (Liverpool), C. Mottram (Liverpool J.M. Uni.), C. Guidorzi
(Liverpool), N. Tanvir (U. of Hertfordshire), C. Mundell (Liverpool),
I. Steele (Liverpool), R. Priddey (Hertfordshire), M. Hughes
(Hertfordshire), R. Smith (Liverpool), A. Gomboc (Liverpool), S. Fraser
(Liverpool), M. Bode (Liverpool), A. Newsam (Liverpool) report:

We observed the optical afterglow of GRB 041006 with the 2.0m Liverpool
Telescope on La Palma. We obtained BVRI imaging commencing 8.2 hours after
the burst. We report preliminary R-band estimates:

R = 20.4 +/- 0.1 mag at Oct 6.92 UT  (exposure time = 600s)
R = 20.6 +/- 0.1 mag at Oct 6.98 UT  (exposure time = 600s)
 
These values were derived applying zero points inferred from the Landolt
standard stars as cited in Fugazza et al (GCN 2782), which result in
measured magnitudes ~0.3 mag fainter than those given in the USNO
catalogue. 

star            RA            Dec           R mag    err
----------------------------------------------------------
U0900_00213234  00:54:47.045  +01:14:05.60  17.75 +- 0.04
U0900_00213423  00:54:50.131  +01:12:10.33  18.90 +- 0.04

In summary, we confirm the R-band magnitude measured by Fugazza et al
(GCN 2782) at 7.07UT.