Canon XSi, modded, Total (HaR)GB 98 min. = RGB 18x3 min., Ha 11x4 min., ISO 1600
Baader MPCC, Baader 7nm Ha Filter
LXD75-SN10 OTA, EQ6 mount, guided w/PHD and EQMOD

This is one of the closest "planetary nebula," named by early observers as such, due to their round "planet-like" image in early telescopes. As all planetary nebulae (including The Medusa Nebula SN2-274, M57 The Ring Nebula, M27 The Dumbbell Nebula, M97 The Owl Nebula, and C55 NGC 7009 The Ghost of Saturn - all shown elsewhere on this site) - The Helix is the result of a star very much like our sun, throwing off its outer layers near the end of its life. That star, known as a planetary nebula nucleus or PNN, is destined to become a white dwarf star. It can be seen as the deep blue star located in the middle of the nebula in this image.

Gases from the star in the surrounding space appear, from our vantage point, as if we are looking down a helix structure. The observed glow of the central star is so energetic that it causes the previously expelled gases to brightly fluoresce.

The Helix Nebula in the constellation of Aquarius lies about 700 light-years away, spanning about 0.8 parsec or 2.5 light-years. Recent images by the Hubble Space Telescope of the Helix Nebula are a composite of newly released images from the ACS instrument and the wide-angle images from the Mosaic Camera on the WIYN 0.9-metre telescope at Kitt Peak National Observatory.

Currently, the Helix nebula's age is estimated to be 10,600+2,300−1,200 years, based solely upon a measured expansion rate of 31 km·s-1.[2]

The Helix Nebula is thought to be shaped like a prolate spheroid with strong density concentrations toward the filled disk along the equatorial plane, whose major axis is inclined about 21° to 37° from our vantage point. The size of the inner disk is 8ª19 arcmin in diameter (0.52 pc); the outer torus is 12ª22 arcmin in diameter (0.77 pc); and the outer-most ring is about 25 arcmin in diameter (1.76 pc). We see the outer-most ring as flattened on one side due to its colliding with the ambient interstellar medium.

Expansion of the whole planetary nebula structure is estimated to have occurred in the last 6,560 years, and 12,100 years for the inner disk. Spectroscopically, the outer ring's expansion rate is 40 km·s-1, and about 32 km·s-1 for the inner disk.


The information above is taken from Wikipedia: http://en.wikipedia.org/wiki/Helix_Nebula