GRB040403 observations from Nyrölä Observatory

The INTEGRAL error circle of GRB040403 imaged April 3, 2004 20:05-23:50 UT through Rc filter.

Copyright: Nyrölä Observatory, 2004

NUMBER:  2563
SUBJECT: GRB 040403: Optical observations
DATE:    04/04/04 22:59:39 GMT
FROM:    Arto Oksanen at Nyrola Obs., Finland   

P. Tikkanen and A. Oksanen on behalf of Nyrola observatory GRB Team 
and AAVSO International High Energy Network report:

A 24 x 16 arcmin field covering the INTEGRAL error circle of GRB
040403 (GCN 2560) was imaged with the 0.4m SCT of the Nyrola
Observatory starting at April 3, 2004 20:05 UT, 15.0 hours 
after the burst. Observation was taken under quite poor conditions,
bright moonlight, northern lights and moderate seeing.
Total of 53 four minute Rc-exposures, exposure time of 12720 seconds, 
were sigma reject combined and compared against the Digitized Sky 
Survey (DSS2R). 

No new objects brighter than DSS2 plate limit was detected, but some 
fainter objects were also present inside error circle. The faintest 
stars on the combined image are about Rc=20.4 (USNOA2.0 reference).

The combined image is available on web:

Nyrola observatory wants to express gratitude to AAVSO for loaning
the CCD camera and to Wihuri foundation for generous grants for the 

The AAVSO International High Energy network is grateful for a
generous grant from the Curry Foundation and to NASA for the 
financial support for the High Energy Workshops for Amateur 

Full resolution images

Cropped 5x5 arc mins containing the error circle

Northern lights during observations