M57, the Ring Nebula, is one of the most beautiful objects
in the Northern sky. It was discovered by Antoine Darquier de Pellepoix
in 1779. M57 is believed to be a planetary nebula, similar in
structure to M27.
The Ring Nebula contains a central star, discovered by the German
astronomer, F. von Hahn, in 1800. Observing the central star is one
of the great challenges of amatuer astronomy. The star itself is a
planet-sized white dwarf. The Ring Nebula was probably formed when
this central star exploded long ago.