[vsnet-grb-info 2184] GRB050922C: Optical Observations

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  4023
SUBJECT: GRB050922C: Optical Observations
DATE:    05/09/23 04:43:10 GMT
FROM:    Aaron Price at AAVSO  <aaronp at aavso.org>

D. T. Durig (Cordell-Lorenz Observatory - University of the South) and A.  
Price (AAVSO) report on behalf of the AAVSO International High Energy
network on optical observations of GRB050922C.

After glow reported by Rykoff et al (GCN #4011) was visible in 2 hours of
exposures. The first three measurements are below and a link to the rest
is in the full report at the bottom of the e-mail. Uncertainty is
estimated at +/-0.2 mag.

 09 23.03833 19.1 Rc
 09 23.07725 19.5 Rc
 09 23.10989 20.1 Rc

 The AAVSO would like to thank the Curry Foundation and NASA for their
support of the AAVSO International High Energy Network.

 Name: Dr. Douglas T. Durig
 email: ddurig at sewanee.edu
 Observer: D. T. Durig, K. T. Crockett, L. R. Johnson
 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/5.9      1770 mm
 CCDVendor: SBIG ST-8E
 CCDDetector: KAF-1600E
 CCDSize: 1530x1020 binned 3x3 for 510x340
 CCDPixelScale: 3.14 arc sec per pixel
 CCDFOV: 26.7x17.8 full, 13.3x8.9 cropped submitted
 Object: GRB050922C
 ObsDate: 2005 09 23
 ObsMidPointTime: 01:51:14 UT
 TimePerFrame: 300 sec
 NumberOfFrames: best 24 out of 30
 Filters: CR
 Processing: dark,flat, register,co-add, 1/2 frame crop
 Seeing: 5-6 arc sec
 LimitingMag: ~21.5 ???
 Sky: clear, but very gusty winds
 afterglowmag: 19 fading to 20 over two hours time
 afterglowerr: 0.2 mag
 compstars: 94 UCAC, 188 B1.0 subframe
 Report: Full frame covers entire error box. After glow reported by Rykoff et al (GCN 4011) was visible in single 300 sec exposure but 6 frames were added to improved S/N for measurements. We measure a position of 
21 09 33.10 -08 45 30.2 
First three photometric measurements shown below.
We have posted our first 2 hours of exposure at http://arthur.sewanee.edu/obsv/view.php

 comments: 09 23.03833 21 09 33.10 -08 45 30.2 19.1 R 
09 23.07725 21 09 33.12 -08 45 30.4 19.5 R      
09 23.10989 21 09 33.12 -08 45 30.7 20.1 R      

A FITS image has been uploaded to ftp://ftp.aavso.org/grb/Dr.DouglasT.Durig_GRB050922C_2453636.66853_.fits