TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3916 SUBJECT: GRB050904: Optical Observations DATE: 05/09/04 16:19:06 GMT FROM: Aaron Price at AAVSO Dr. D.T. Durig (Cordell-Lorenz Observatory, University of the South), Dennis Hohman (Stone Edge Observatory) and Aaron Price report on behalf of the AAVSO International High Energy Network on observations of the field of GRB050409 (GCN 3910; Cummings et al.). Durig does not detect any afterglow with SNR>3 on unfiltered images centered at 08:30:59 UT. However, sources do exist with an SNR=3 at locations near that reported in GCN #3913 (Haislip et al.). Locations and magnitude: 00 54 51.38 14 04 48.9 20.0 mag 00 54 50.42 14 05 30.6 20.1 mag 00 54 51.55 14 05 28.8 20.2 mag Full details, including a link to the FITS image is available at the bottom of this notice. Also, Hohman observed the field with an Rc filter centered on 06:18 UT and does not report any afterglow to Rc=18.6. Details on his observation are also below. The AAVSO thanks the Curry Foundataion for their continued support of the AVSO International High Energy Network. Report filed on Sun Sep 4 07:54:36 2005: Name: Dr. D. T. Durig email: ddurig@sewanee.edu Observer: D. T. Durig, A. P. Long, A. L. Yacko, J. L. Rouquette, J. C. Heiss Site: Cotrdell-Lorenz Observatory Location: Sewanee, Tenn, USA LatitudeLongitude: 35 12 N 85 55 W Elevation: 600m Scope: SCT 0.30 m ScopeFocalRatio: f/5.9 1760 mm CCDVendor: SBIG STL-1001E CCDDetector: KAF-1001E CCDSize: 1024x1024 CCDPixelScale: 2.8 CCDFOV: 48x48 full, 12x12 quater shown Object: GRB050904 ObsDate: 2005 Sept 4 ObsMidPointTime: 08 30 59 UT TimePerFrame: 300 sec NumberOfFrames: 37 Filters: CR Processing: dark, flat, register, add, 1/4 frame crop Seeing: ~6 LimitingMag: approx. 20.5 Sky: clear but windy afterglowmag: NA afterglowerr: NA compstars: 850 USNO B1.0 in Full Frame Report: Total exposure 185 minutes (37x300 sec= 11,100 sec ). I see no afterglow at the reported position(s) above my detection limit but there appears to be three very dim diffuse sources nearby at 00 54 51.38 14 04 48.9 20.0 mag 00 54 50.42 14 05 30.6 20.1 mag 00 54 51.55 14 05 28.8 20.2 mag All three are near my limiting mag with sigma equal to 3. In the noise I measure 00 54 49.69 14 05 08.5 21.9 mag but with sigma equal to 1.5 and below my detection limit of 20.5 mag. A FITS image has been uploaded to ftp://ftp.aavso.org/grb/Dr.D.T.Durig_GRB050904_2453617.99625_.fits -------------------- Report filed on Sun Sep 4 03:36:21 2005: Name: Dennis Hohman email: dennishohman@adelphia.net Observer: Dennis Hohman HDF Site: Stone Edge Observatory Location: Orchard Park, NY USA LatitudeLongitude: -78 45, 42 46 Elevation: 290M Scope: C8 200mm ScopeFocalRatio: 1200 CCDVendor: ST7XME CCDDetector: KAF402E CCDSize: CCDPixelScale: 1.55 CCDFOV: 19x13 Object: GRB050904 ObsDate: 09/04/05 ObsMidPointTime: 06:18 TimePerFrame: 240 sec NumberOfFrames: 8 Filters: R Processing: Darks,Flats, bias, coadd Seeing: 4 LimitingMag: 18.6 Sky: mostly clear with occasional patchy clouds afterglowmag: afterglowerr: compstars: Report: Full error circle covered. No new object observed to a limiting magnitude of 18.6 based USNO A2.0 catalog comments: A FITS image has been uploaded to ftp://ftp.aavso.org/grb/DennisHohman_GRB050904_2453617.81691_.fits