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Naked nebula reveals astronomy’s colour tricks

A raw picture of the Helix nebula reveals the processing involved in creating stunning astronomical images
Naked nebula reveals astronomy's colour tricks

(Image: ESO)

It鈥檚 probably the blandest image of the Helix nebula you鈥檝e ever seen. Pictures of nebulas often display their gigantic forms in vivid hues, but that鈥檚 because several views have been combined to produce the final image.

The raw image above, captured by a device that images radiation at the in Chile鈥檚 Atacama desert, is broken up into eight frames, each imaged by a different detector. The gaps created by the grid are usually filled in using pictures taken from slightly different vantage points.

After a bit of processing to remove defects, and by combining the monotone view with images shot through blue, green and red filters, the colour composite below was produced.

Naked nebula reveals astronomy's colour tricks

(Image: ESO)

Filters are used to pick up light from specific gases because molecules of each gas reflect light of a different wavelength. The resulting image essentially provides a colour-coded but representative interpretation of the nebula鈥檚 chemical make-up.