Messier 57 - The Ring Nebula Credit: NASA/ESA HST, Spitzer ST, Giuseppe Donatiello RA: 283,387° Dec: 33,026 The Ring Nebula (Messier 57 or NGC 6720) is a planetary nebula in Lyra and it is illuminated by a central white dwarf or planetary nebula nucleus (PNN) of 15.75 visual magnitude. All the interior parts of this nebula have a blue-green tinge that is caused by the doubly ionized oxygen emission lines at 495.7 and 500.7 nm. In the outer region of the ring, part of the reddish hue is caused by hydrogen emission at 656.3 nm. M57 is an example of the class of planetary nebulae known as bipolar nebulae. In this composition is all the resolution power of the Hubble Space Telescope. If you download the image and observe it with a good monitor through suitable software, you will be able to see even finer details. The problem is that HST images are rarely published in actual resolution, even NASA and ESA. They are often images rescaled for the web. Also consider that this is also a cutout and uses data from the Spitzer Space Telescope as well.