TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3340 SUBJECT: GRB050502A: Optical Observations DATE: 05/05/03 02:42:36 GMT FROM: Aaron Price at AAVSO D.T. Durig (Cordell-Lorenz Observatory - The University of The South) reports on behalf of the AAVSO International High Energy Network on optical observations of GRB050502A (GCN #3323, Gotz et al.): Durig reports the following rapidly fading behavior: Date (UT) Mag 02.17880 19.8 02.18243 20.8 02.18606 20.3 02.18969 20.4 02.19331 20.5 02.19694 20.9 02.20056 21.4 02.20418 21.4 02.20781 21.0 02.21144 21.3 Observations were made unfiltered based on a V zeropoint. Uncertainly is +/- 0.4 magnitudes. Details of the observation are below along with a link to the co-added FITS image. Full Observation Details Name: Dr. Douglas T. Durig email: ddurig@sewanee.edu Observer: D. T. Durig ( CLW01) Site: Cordell-Lorenz Observatory Location: Sewanee, TN, USA LatitudeLongitude: 35 12 N 85 55 W Elevation: 600 m Scope: SCT 0.30 m ScopeFocalRatio: f/5.8 1766 mm FL CCDVendor: SBIG ST1001E CCDDetector: KAF1001E CCDSize: 1024x1024 CCDPixelScale: 2.8 arc sec/ pixel CCDFOV: 48x48 full, 12x12 cropped submitted Object: GRB050502 ObsDate: 2005 05 02 ObsMidPointTime: 2.15912 (04 40 58 UT ) TimePerFrame: 300 sec NumberOfFrames: 11 Filters: CV Processing: dark, flat, registered, added, quarter frame cropped Seeing: 4 to 5 arc sec LimitingMag (SNR=3): 21.0 ??? Sky: very clear afterglowmag: 20 fading to 21 during first hour afterglowerr: 0.4 compstars: 900 USNO B1.0 stars Report: I could see the afterglow candidate in my first few images but it was fading fast and I had to stack to see it well in later images. Ave Position:13 29 46.28 +42 40 27.7 I get the following magnitudes for co-added (10min) frames: 02.17880 19.8 CV 02.18243 20.8 CV 02.18606 20.3 CV 02.18969 20.4 CV 02.19331 20.5 CV 02.19694 20.9 CV 02.20056 21.4 CV 02.20418 21.4 CV 02.20781 21.0 CV 02.21144 21.3 CV A FITS image has been uploaded to ftp://ftp.aavso.org/grb/Dr.DouglasT.Durig_GRB050502_2453492.77287_.fits The AAVSO thanks the Curry Foundation for their continued support of the AAVSO International High Energy Network.