TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  4451
SUBJECT: GRB 060108: Mitsume optical observations
DATE:    06/01/09 08:55:05 GMT
FROM:    Nobuyuki Kawai at Tokyo Tech  <nkawai@hp.phys.titech.ac.jp>

K. Yanagisawa (OAO/NAOJ), H. Toda, and N. Kawai (Tokyo Tech) report
on behalf of the Mitsume collaboration: 

"We have observed the field of GRB 060108 (Oates et al. GCN 4443,
Sakamoto et al. GCN 4445) with the three-color Mitsume 50 cm
telescopes at Okayama, Japan starting at 15:06:34 UT (T_burst+0.46h)
until 15:58:02 UT (T_burst+1.3h) for an effective exposure of 40 min
(60sec x 40).

We did not find an object in the XRT error circle (Page et al. GCN
4444) with the following 10-sigma upper limits that are calibrated
against the SDSS data (Cool et al. GCN 4448) where conversion for Rc
and Ic magnitudes were made using the formula by Smith et al. (2002):

 g': 19.4
 Rc: 18.9
 Ic: 18.2

The images obtained at Okayama can be viewed at 
http://bragi.oao.nao.ac.jp/support/telescope/grb50/images/GRB060108A.pdf"