The Ring Nebula (also catalogued as Messier 57, M57 and NGC 6720) is a planetary nebula in the northern constellation of Lyra. Such a nebula is formed when a star, during the last stages of its evolution before becoming a white dwarf, expels a vast luminous envelope of ionized gas into the surrounding interstellar space.
M57 is 2,570 light-years from Earth. It has a visual magnitude of 8.8 and a dimmer photographic magnitude, of 9.7. Photographs taken over a period of 50 years show the rate of nebula expansion is roughly 1 arcsecond per century, which corresponds to spectroscopic observations as 20–30 km s−1. M57 is illuminated by a central white dwarf or planetary nebula nucleus (PNN) of 15.75v visual magnitude.
![An early attempt photographed with CPC925 reflector telescope and Nikon D800 camera in Stuvsta, September 2015. M57, Ring nebula](https://astro.hal1.se/wp-content/uploads/cache/2023/04/m57-precalibrated_integrated_dbe/4282397086.jpg)
M57, Ring nebula
An early attempt photographed with CPC925 reflector telescope and Nikon D800 camera in Stuvsta, September 2015.
![Photographed with APO107 refractor telescope and Nikon D800 camera in Åva October 2016. 12 min exposure. M57, Ring nebula](https://astro.hal1.se/wp-content/uploads/cache/2023/04/m57_6st_120s_rgb_ps/375962645.jpg)
M57, Ring nebula
Photographed with APO107 refractor telescope and Nikon D800 camera in Åva October 2016. 12 min exposure.
![Photographed with APO107 refractor and Nikon D800 camera in Stuvsta September 2016. Exposure was 9*30s. M57, Ring nebula](https://astro.hal1.se/wp-content/uploads/cache/2023/04/m57_9st_30s_lrgb/4005793112.jpg)
M57, Ring nebula
Photographed with APO107 refractor and Nikon D800 camera in Stuvsta September 2016. Exposure was 9*30s.