| Planetary
Nebula
NGC 40, PNG 120.0+09.8, PK 120+09.1, ARO 1 Integrated Visual Magnitude: 10.7 Apparent Diameter: 1.6' Magnitude of central star: 11.6 Distance: 3,700 ly Actual Diameter: 1.7 ly Minimum requirements to view: 6-inch scope and dark skies |
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.
A six-inch view at 50x.
North is down and east is right.
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.
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.
| Millennium
Star Atlas Vol I Chart 24
Sky Atlas 2000 Chart 1 Uranometria 2000 Vol I Chart 3 |
