#ngc 7293

[quiltofstars]

The Helix Nebula, NGC 7293 // Xinran Li

[spacewonder19]

NGC 7293: the Eye of God from CFHT

[thouartadeadthing]

[shehungthemoon]

Helix Nebula

Clockwise: Optical, X-Ray, Infrared, Ultraviolet

Bottom: Composite

Credit: X-ray: NASA/CXC/SAO; UV: NASA/JPL-Caltech/SSC; Optical: NASA/ STScI/M. Meixner, ESA/NRAO/T.A. Rector; Infrared:NASA/JPL-Caltech/K. Su; Image Processing: NASA/CXC/SAO/N. Wolk and K. Arcand

[verseinfinity]

Helix Nebula

[krakenmare]

NASA Galaxy Evolution Explorer: Ultraviolet image of NGC 7293, also known as the Helix Nebula - the nearest example of what happens to a star as it evolves into a white dwarf (May 5, 2005)

[anavar-immela]

Helix Nebula - NGC 7293

[shaythempronouns]

The Helix Nebula / Eye of God

A planetary nebula in Aquarius

I got another 2 hours of exposure time on the Helix Nebula in the Aquarius constellation and integrated it with my data from last year (about another 2h) to produce this shot. This is a narrowband image made from captured hydrogen and oxygen emissions.

The Helix Nebula is an absolutely gorgeous target specifically because of its rarity. Most planetary nebulae (the products of stars collapsing into white dwarfs) are extremely small because they're far away. The Helix isn't any bigger than them, but it's incredibly close to us, at just under 700 Ly from Earth, which makes it appear 20 times the linear size of other planetary nebulae (e.g. the Crab Nebula or the Ring Nebula).

Musings on the acquisition process after the cut.

This is easily the hardest target I've ever shot. From the USA, it barely rises above 20 degrees, giving a pretty short window to shoot it each night and more atmosphere to shoot through, magnifying the effects of poor seeing. Aquarius has a relatively low density of bright stars, which makes guiding frustrating at poor focal ratios (which are unavoidable at high focal lengths on any kind of budget). And, of course, the Helix is fairly dim and diffuse, requiring lots of exposure time to capture good enough signal for an image. All that together meant that the two hours of data I captured for this shot took five clear nights to pull together. An absolute mess.

I achieved the gold effect at the borders with some slight hue shifting - that area isn't quite synthetic, but is instead the place where the oxygen emissions at the core overlap with the hydrogen emissions of the edges. By slightly bumping the green channel and then stretching the hue to push green toward its adjacent colors (yellow and blue), you get a golden color from the edge of the hydrogen.