TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  926
SUBJECT: GRB010126, TNG R-band observations
DATE:    01/01/29 16:53:29 GMT
FROM:    Nicola Masetti at ITeSRE,CNR,Bologna  <masetti@tesre.bo.cnr.it>

N. Masetti, E. Palazzi (ITeSRE, CNR, Bologna), M. Pedani, A. Magazzu,
F. Ghinassi (TNG) and E. Pian (OATs, Trieste), on behalf of a larger
collaboration, report:


"We acquired optical R-band images of the central part of the 
GRB010126 Ulysses/Konus/RXTE error box (Hurley et al., GCN #922) 
on 2001 Jan. 27.26 and 28.27 UT (i.e. 21 and 45 hours after the GRB) 
with TNG+Dolores. The total exposure time was 10 minutes for each epoch. 
Seeing was 1.3 and 1.7 arcsec on the two epochs, respectively. 
The images covered about 60% of the GRB error box.

Photometric calibration was performed using the USNO-A2.0 catalog star
U1350_08031829, with magnitude R = 17.9 and coordinates (J2000) 
RA = 11 57 10.29; Dec = +49 46 58.9.

The comparison between the two epochs does not reveal any object
with significant brightness variation down to a 3-sigma limiting
magnitude R ~ 23.5 .
The object reported by Bartolini et al. (GCN #924) is well detected on
both epochs and is constant within the measurement errors at magnitude
R = 21.29 +- 0.05 (excluding zero-point calibration uncertainties).
This is consistent with the findings by Pedersen et al. (GCN #925).".


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