The Helix is at once easy
and difficult to observe. By far the largest of the planetary
nebulae in our sky, the low surface brightness of the Helix makes it
difficult to spot unless you know what you are looking for. Any size
scope can reveal it, and even binoculars will show it as a round,
hazy, smudge of light.
The trick to
successfully observing the Helix is to use a wide field of view. You
will need relatively light-pollution-free skies and your
lowest-power eyepiece. At least a 1/2o
field of view is required to find this nebula. Something closer to 1o
is optimum. This nebula extends some 13', making it over ten times
as large as it's cousin, the famous Ring Nebula.
Look for a round spot
in the sky that is slightly brighter than the background. Once
found, use averted vision to see the large, slightly darker central
region.
The view in a 6"
telescope at 50x. North is down and East is right. An image of the
nebula derived from the Digital Sky Survey has been overlaid to
provide a realistic representation of what you may see in the
eyepiece. You may need to adjust your monitor to see the nebula.
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