This planetary is one of
the gems of Autumn in larger telescopes, although it is visible in
smaller scopes as a round haze. The relatively bright central star
is an easy target for six inch or larger telescopes.
In my
six inch, NGC 40 was easily found tucked away between two 10th
magnitude stars. It was obvious even at 50x. The central star was
easily visible. At higher magnification, this planetary was a bit of
a disappointment as I was not able to see any hint of structure or
color.
A six-inch view at 150x. North
is down and east is right.
Long exposure
photographs such as the one above show asymmetry. Some of this
detail is visible in larger instruments, which reveal knots in the
outer ring and a "Z" shaped structure in the disk.
McNeil describes it as "an irregular disk with traces of ring
structure plus an irregular disk and a fainter spherical
envelope." North is down and east is right.
The central star of
this nebula presents a bit of a puzzle. It is hot enough to excite
the nebula to a higher state than that observed. This can be
explained as the result of shielding material near the star.
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