TITLE:   GCN CIRCULAR
NUMBER:  3292
SUBJECT: GRB050418: Null Optical Observations
DATE:    05/04/18 21:28:56 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 GRB050418 (Sakamoto
et al,; GCN #3288).

Observations by Monard do not reveal ay new source compared with the
POSS-II red plates down to an unfiltered limiting magnitude of 16 at an
observation midpoint time of 16:50 (UT). As previously reported in GCN
#3288, the field was relatively close to the Sun therefore close to the
horizon.

Details of the observation are below.

Name: Berto Monard
email: bmonard@mweb.co.za
Site: Bronberg Observatory
Location: -25 =BA 54' 48", 28=BA 26' 44"E
Elevation: 1590m
Scope: LX200 12"
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: 050418
ObsDate: 050418
ObsMidPointTime: 16 50 UT
Exposure per frame: 28 sec
NumberOfFrames: 33
Filters: none
Processing: dark/flat
Seeing: good (about 3 arcsec)
LimitingMag: 16CR for stack of 13 images
Sky: partly cloudy / 1/2 moon / target field close to horizon
afterglowmag: NA
Report: the observed star field was centered on 02h 57m 22s -18d 32' 15"
(2000). The obtained deep image was compared visually to a DSS-2 red image
centered on the above coordinates.

No new object showed in the quoted error box down to a magnitude of 16CR.

Note: The actual observation period was very short due to the
circumstances and no further observations were possible.