Portal:Astronomy/Picture/Week 26 2006
< Portal:Astronomy | Picture
George Abell is well known for compiling a catalogue of galaxy clusters but also catalogued planetary nebulae with low surface brightnesses. Abell 39 is extremely spherical in shape, although a mystery for astronomers is that the central star does not lie exactly at the centre of the sphere, but is displaced by about 0.1 light years.