M57, The Ring Nebula -- This
image was taken using the ST1001E on the 38-inch Cassegrain.
The famous ring nebula M57 is
often regarded as the prototype of a planetary nebula, and a showpiece in the
northern hemisphere summer sky. The nebula is between 1000 and 3000 light
years from the Sun. Recent research has confirmed that it is most
probably, actually a ring (torus)
of bright light-emitting material surrounding its central star. At the very
center of the nebula the dying star, a white dwarf, can be seen. The nebula
is the expanding outer layers of this dying star
and the remaining core is the white dwarf. These nebula are called
"planetary" nebula because early astronomers thought they resembled planets
when viewed through a telescope.