The Helix (also known as "the Eye of Sauron") is the closest of the bright planetary nebulae to the solar system (about 700 light years distant), and covers an area of sky similar to that of the full moon (it actually spans about 2.5 light years of space). It represents ejecta from a dying star at the centre, with its outer layers having been blown off over the past ten or so millennia.
This image was taken using a 120mm achromat refractor with narrowband filters (Ha, OIII and SII) and RGB stars. A synthetic luminance was created using an exposure based weighting. The camera was an Orion Starshoot G3 monochrome, upscaled via drizzling. Two different colour palettes (OIII:OIII-Ha:Ha and Ha:Ha-OIII:OIII and HST) are shown.
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- Helix_OIII-Ha.jpg (199.01 KiB) Viewed 3381 times
Captured throughout Oct 2014. Pre-processed with flats (light box), bad pixel map (based on 70 darks) and bias in Nebulosity. Aligned and Drizzled in DSS. Post-processed in StarTools.
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- Helix_Ha_OIII_SII.jpg (195.33 KiB) Viewed 3381 times
Full details and high rez images are on Astrobin:
http://www.astrobin.com/135036/B/