TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  3159
SUBJECT: GRB050331: No Afterglow Detected
DATE:    05/03/31 20:47:13 GMT
FROM:    Aaron Price at AAVSO  <aaronp@aavso.org>

 B. Monard and A. Price report on behalf of the AAVSO International High Energy Network on 
optical observations of the field of GRB050331 (GCN#3156 Palmer et al.).

 A field centered on the coordinates of the XRT position in GCN #3155 (Burrows et al.) was
observed at midpoint time of 19:03 UT and compared with the DSS/POSS red plate. The CCD
was unfiltered but with a red zeropoint response.

 No new source was identified down to a limiting magnitude (SNR=3) of 20. 

 Full details on the report is below along with a link to the FITS image:

 Report filed on March 31 22:08 UT
 Name: Berto Monard
 email: bmonard@mweb.co.za
 Site: Bronberg Observatory / CBA Pretoria
 Location: -25 º 54' 48", 28º 26' 44"E
 Elevation: 1590m
 Scope: LX200 31cm
 ScopeFocalRatio: f/3.7
 CCDVendor: SBIG, ST-7XME
 CCDPixelScale: about 1.8 arcsec /pixel
 CCDFOV: 21 arcmin (E/W) x 14 arcmin (N/S)
 Object: GRB 050331
 ObsDate: 050331
 ObsMidPointTime: 19 03 UT
 Exposure per frame: 28 sec
 NumberOfFrames: 35 stacked
 Filters: none
 Processing: dark/flat
 Seeing: fair (about 3.5 arcsec)
 LimitingMag: about 21CR for stack
 Sky: open / no moon / object near zenith
 afterglowmag: none down to magnitude 20CR
 Report: the observed star field was set to be centered on 09 22 57 -41 25
 48.
 The obtained deep image was compared visually to a DSS-2 red image over the
 entire error box of 4 arcmin.
 No new object was found to an estimated limit of 20 CR and no further
 observations are planned.
 FITS image is located at http://www.aavso.org/tmp/grb050331.fits