M57

From South Dublin Astronomical Society

M57
Type	Planetary nebula
NGC	NGC 6720
Constellation	Lyra
Right Ascension	18h 53.6m
Declination	+33° 02'
Magnitude	8.8
Size	1.4 x 1.0 arc min.
Image:M57 messier image.jpg

Some would argue that the Ring Nebula is one of the finest planetary nebulae in the northern sky. Although intriniscally quite faint, its small angular size means that it appears more stellar in smaller telescopes and therefore, easier to spot. M57 is also quite easy to locate being almost one third of the way between γ and β lyrae.

At a distance of 2,300 light years, the ring nebula spans around 1.4', however a halo around the main nebulous area extends to over 3' of sky meaning the true diameter of the main nebula is close to .9 light years with the halo structure extending to 2.4 light years.

One of the most interesting facets of this object is it's faint central star. At magnitude 15 a very large telescope (16-20 inches) and very dark skies will be required to detect visually. The star iself is a white dwarf class star with a temperature of around 100,000°Kelvin. Once this star was much like our sun. Studying this nebula we see the probable outcome of our own Sun and solar system. Perhaps in around 6 billion years time a group of extra terrestrial observers will be writing about a beautiful ring of smoke where our solar system used to be.