AAO image reference AAT 15. « Previous || Next »
Top left is NE. Image width is about 25 arc min
Image and text © 1990-2002, Anglo-Australian Observatory, photograph by David Malin.
This faint object is the nearest planetary nebula to the Sun and on deep photographs has a diameter of about half a degree -- the same apparent size as the Sun in the sky. The AAT colour picture shows the brighter parts of the nebula, revealing various ionisation levels within the shell of matter ejected from the central star. The greenish middle portion is evidence of excited oxygen atoms, while the outer red is predominantly light from nitrogen and hydrogen. The smallest of the radial blobs inside the red shell are about 150 astronomical units across (150 times the Earth-Sun distance) and they give this beautiful object its alternative name, the Sunflower Nebula. The Helix is about 400 light years away, or about 100 times more distant than the nearest stars. Click here for bigger image.
Entry from NGC 2000.0 (R.W. Sinnott, Ed.) © Sky Publishing Corporation, 1988:
NGC 7293 Pl 22 29.6 -20 48 s Aqr 12.8 ! pF, vL, E or biNRelated Images
AAT 15a. The Helix nebula, wide field
AAT 15b. The Helix nebula, wide field, no unsharp mask
For details of photographic exposure, search technical table by AAT reference number.