TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  5526
SUBJECT: GRB060904b, optical observations
DATE:    06/09/05 14:41:54 GMT
FROM:    Adalberto Piccioni at Astronomy, Bologna U.  <adb@piccio.org>

G. Greco (Bologna University), F. Terra (Second University of
Roma "Tor Vergata"), C. Bartolini, A. Guarnieri, A. Piccioni
(Bologna University), D. Nanni (INAF/OAR and Second University
of Rome "Tor Vergata"), S. Bernabei (Bologna Observatory),
S. Sclavi(University of Rome "La Sapienza") and G. Pizzichini
(INAF/IASF Bologna) report:

On Sept. 5 we observed the field of GRB 060904b (Grupe et. al.,
GCN 5165) with the 152 cm Cassini Telescope located in Loiano,
equipped with BFOSC (seeing 1".5).
The photometry is based on the SDSS stars (J035252.20  -004344.1,
J035249.70  -004345.8 , also quoted in GCN 5507 by Cool et al.)
and the trasformation derived from Lupton (2005).
For the OT detected by Klotz et al. (GCN 5508) we find the
following magnitudes:
..Mean..UT .......Filter........Exptime (s).......magnitude
Sept...5.111........Rc............900............21.75+/-0.11
Sept...5.123........Rc............900............21.74+/-0.12
Sept...5.145........Rc............900............21.8 +/-0.2

One of our images is available in a public directory from where
it can be retrieved by sftp by using:
hostname: ermione.bo.astro.it
username: publicGRB
password: GRB_bo
directory: GRB060904b