TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  3249
SUBJECT: GRB 050412: Early Optical/Ultraviolet Observations with
DATE:    05/04/12 14:41:30 GMT
FROM:    Pete Roming at PSU  <roming@astro.psu.edu>

P. Roming (PSU), V. Mangano (INAF-IASF/Palermo), S. T. Holland (GSFC-USRA), 
W. Landsman (GSFC), P. Schady (PSU & MSSL), D. Hinshaw (GSFC-SPSYS), S. 
Kobayashi (PSU), A. Blustin (MSSL), N. Gehrels (GSFC), K. Mason (MSSL), J. 
Nousek (PSU), and A. Wells (Leicester) on behalf
of the Swift UVOT team report:

The Swift Ultraviolet/Optical Telescope (UVOT) observed the field of GRB 
050412 (Cummings et al., GCN 3237) starting at 05:45:40 UT on 12 April 
2005.  We find no evidence for a source in the 5 arcsecond radius XRT error 
circle (Tamburelli et al., GCN 3241) in the UVOT data.  The 3-sigma 
limiting magnitudes in a 3.5 arcsecond radius circular aperture is V = 19.1 
with a systematic uncertainty of 0.1 mag due to uncertainty in the 
preliminary flight photometric zero point.