[vsnet-grb-info 2077] GRB050904: Optical Observations

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  3916
SUBJECT: GRB050904: Optical Observations
DATE:    05/09/04 16:19:06 GMT
FROM:    Aaron Price at AAVSO  <aaronp at aavso.org>

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 at 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 at 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