NGC 7293 - The Helix Nebula.

The Helix Nebula is a large planetary nebula which spans about the same area of the sky as half the apparent diameter of the Moon. Photographic images of the Helix nebula show the nebula to be even larger, as large as the apparent size as the entire Moon. The nebula owes its large apparent size to its relatively close proximity of just 450 light-years. At about 1.5 light years in diameter the Helix nebula was formed when the central star shed its outer layers into space, stars do this in an attempt to survive, shedding fuel-exhausted layers to re-balance mass and gravity.

Its helical spring-like appearance gives rise to its name the Helix Nebula, a mathematical name for a three dimensional curve that lays on a cylinder or more generally speaking a spiral form. If you examine this image of the Helix Nebula and trace the outer red shapes of the nebula, you may recognise that it appears like two rings joined outlining its cylindrical shape which appears from our perspective to lay on its side and point off to the lower left.