The Ring Nebula, catalogued as both Messier 57 (M57) and NGC 6720, is a planetary nebula in the northern constellation of Lyra. Such a nebula is formed when a star explodes, expelling a vast luminous envelope of ionized gas into the surrounding interstellar space and leaving behind a much shrunken white dwarf.

This nebula is small and faint; I'm astonished that Messier could find it! It's at the limit of my modern rig with long digital camera exposures. This picture was assembled from 150 exposures at 30 seconds each - I didn't have guiding working at this time and 60 seconds unguided is about as long an exposure as is worth taking with my telescope. The first image in this set shows a stretched stacked full frame image - one that has been put together from a stack of "light" frames, making one image out the 150 individual frames, and having the equivalent of a 75 minute exposure; this image is then "stretched" to pull out faint detail. Stretching involves making the light colors much lighter and the dark colors much darker in a clever way that accounts for the different wavelengths of light, hot pixels and so on. Even after stretching the target is tiny and little detail can bee seen using my 90mm wide angle telescope.

The open cluster in this image set is Messier 39. It is a typical small open cluster of stars, adding up to about 232 solar masses spread over 30 light years. It is centered around 1010 light years away.