Messier 57 (Lyra)
Fig. 1 - One of the most iconic and beautiful planetary nebulae: The 'Ring Nebula' Messier 57 in Lyra, photographed with a 16-inch f/4.5 Dob on an equatorial platform.
| Object name: | Constellation: | Coordinates: | Apparent size: | Visual brightness: |
|---|---|---|---|---|
| Messier 57 (= NGC 6720) | Lyra | 18h54m / +33°02' | 3.0' x 2.4' | 8.8 mag |
The planetary nebula Messier 57 (NGC 6720, "Ring Nebula") in the constellation of Lyra. A nebula of this kind forms when a dying star, in the final phase of its life before transitioning into a white dwarf, releases a vast and glowing shell of ionized gas that drifts outward into the surrounding interstellar space. Photographs taken over a period of 50 years show the rate of nebula expansion is roughly 1 arcsecond per century.
The interior parts of the nebula have a blue-green tinge that is caused by the doubly ionized oxygen emission. In the outer region of the ring, part of the reddish hue is caused by hydrogen emission. The observed nebulosity has been currently estimated to be expanding for approximately 1,610 ± 240 years. Messier 57 is 2567 ± 115 light-years from Earth and was discovered by Charles Messier in 1779 (source: Wikipedia).
Exposure time: 56min (28x approx. 2min), taken on June 30 / July 1, 2014 at ISO 400. Processing with Deep Sky Stacker and Photoshop. No calibration frames were used.
Canon EOS 450D Baader modified camera, TeleVue Paracorr Type II coma corrector, 16" f/4.5 "Ninja" dobsonian telescope riding on a dual-axis Tom Osypowski equatorial platform, Lacerta MGEN autoguider, Lacerta off axis system.
Field of view comparison: image of the moon with the same setup.
Fig. 2 - Search chart for Messier 57. Copyright 2025 'The Mag-7 Star Atlas Project', www.siaris.net.