Click on the image for a full resolution version   Messier 57, also known as M57, NGC 6720 and the Ring Nebula, is a very well known planetary nebula. It has been thoroughly studied. Its exact distance was not precisely known until 2018, when the GAIA satellite determined it to be 2,283 light years. Usual … Continue reading Messier 57. NGC 6720. The Ring Nebula