GCN Circular 12369

Arto Oksanen (Hankasalmi Obs., Hankasalmi, Finland), Caisey Harlingten 
(Harlingten Observatory, San Pedro de Atacama, Chile), Bradley Schaefer 
(LSU), and Matthew Templeton (AAVSO) report the following follow-up 
optical observation of the error box of GRB 110918A (Hurley et al., GCN 
Circ. #12357):

A. Oksanen (Hankasalmi Obs., Hankasalmi, Finland) reports an observation 
of the error box of the intense, long GRB 110918A (Hurley et al., GCNC 
#12357; Golonetskii, et al., GCNC #12362) using the Harlingten Observatory 
0.5-m Planewave telescope with Apogee Alta-U42D9 CCD located in San Pedro 
de Atacama, Chile.  Ten, 60-second unfiltered observations of the field 
containing the GRB error box were made; the coadded image has a midpoint 
time of 2011 Sep 20 07:33 UT (JD 2455824.8146), approximately 34 hours 
post burst.  We find the point source detected by Mangano et al. (GCNC 
#12364) and Tanvir et al. (GCNC #12365) at a preliminary magnitude of 
R=19.0 measured relative to the nearby USNO-A2.0 star 0600-00854967 
(B=18.8,R=17.7).

Coadded images of the field are available at the following links:

FITS: http://pilvi.dyndns.org/arto/GRB110918A_median.fit

JPEG: http://pilvi.dyndns.org/arto/GRB110918A_median.jpg


The AAVSO International High Energy Network was made possible through 
grants from the Charles Curry Foundation and from NASA, and is supported 
through the AAVSO Endowment.