Other Names: Helix Nebula PN G036.1-57.1, PK 036-57.1, ARO 17
Optics: Planewave 20" (0.51m) CDK f/4.5
Mount: Planewave Ascension 200HR
Camera: FLI-PL6303E CCD camera
Filters: HaRGB
Exposure: 150 Mins, [30 x 300s] Ha
Accessories: 2280mm (0.66 Focal Reducer) no guider used
Location: Siding Spring, New South Wales, Australia
Date: August 1st to 3rd, 2013
Notes: Image acquisition with Maxim DL Pro using ACP automation.
Processing: Image calibration, align, and combine in Maxim DL Pro. Levels, curves, crop and resize in Photoshop.
Calibrated w/50 Darks, 100 Bias, 15 Flats . CCD temperature was -35C. Image was taken using ITelescope.net's rental scope (T30) in Australia.

HaRGB version: http://astromarina.zenfolio.com/p43889445/h2324115#h2324115

The Helix Nebula, also known as The Helix, NGC 7293, is a large planetary nebula (PN) located in the constellation Aquarius. Discovered by Karl Ludwig Harding, probably before 1824, this object is one of the closest to the Earth of all the bright planetary nebulae.[7] The estimated distance is about 215 parsecs or 700 light-years.

The Helix Nebula is an example of a planetary nebula, or 'planetary' formed at the end of a star's evolution. Gases from the star in the surrounding space appear, from our vantage point, as if we are looking down a helix structure. The remnant central stellar core, known as a planetary nebula nucleus or PNN, is destined to become a white dwarf star. 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.

Currently, the age is estimated to be 10,600 years +/-2,300 to 1,200, based solely upon a measured expansion rate of 31 km/s