TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3292 SUBJECT: GRB050418: Null Optical Observations DATE: 05/04/18 21:28:56 GMT FROM: Aaron Price at AAVSO 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.