North is to the top.
NGC 3239, ARP 263, is a highly disturbed and irregular galaxy. It is located in the constellation Leo, at a distance of about 49 million light-years. In 1999, J. R. Hargis and Caroline Simpson stated that the galaxy shows signs of both early and late effects of interaction with another galaxy. Unfortunately, the other galaxy has not been identified.
The NED database identifies 91 HII regions in NGC 3239. However, these regions are difficult to show... even with added Ha filtered data.
Exposure Details
Ha 570 min (19 x 30 min)
Lum 360 min (24 x 15 min)
RGB 675 min (15 x 15 min, each)
Taken with an SBIG STL-11000 camera, using Astrodon filters and an RCOS 12.5" scope
For more info see URL...
http://bf-astro.com/ngc3239/ngc3239.htm