Abell 39 is a low surface brightness planetary nebula located in Hercules. At the centre is a blue/white dwarf star at the end of its life. About 20,000 ago, this star expelled a glowing shell of gas creating the near spherical gas cloud that can be seen today. This is estimated to be 5 light years across and about 6000 light years away. Over time, the gas will spread over a very wide area of space and will eventually be used for creating new stars.
Very distant background galaxies can also be seen in the image, including one that is visible through the translucent gas of the nebula (see annotated image).
This LRGB image was taken with my Esprit 150 and also has an OIII blend into the blue channel, it represents approximately 17 hours integration time.