NGC 40: The Bow-Tie Nebula

Posted byWayne McGrawPosted inCaldwell Object, NebulasTags:,

NGC 40, also known as Caldwell 2 and the Bow-Tie Nebula, is a planetary nebula in the constellation Cepheus, which is best viewed in autumn.

Backyard astronomers with a moderate-sized scope (6+ inches in diameter) may be able to spot this planetary, appearing as a fuzzy patch of light or a smudge. Compared to others, in my opinion, NGC 40 is quite faint for light-polluted skies at magnitude 10.6. However, it’s still possible to see under good conditions. See my observation below.

Historically, the astronomer William Herschel first recorded the object on November 25, 1788, almost 234 years from when I first observed the object from my backyard.1

My Observations

DateNovember 18, 2022
Time8:20 p.m.
LocationSeattle, WA
Magnification169x
ScopeMeade 8″ SCT
Eyepiece12mm
SeeingGood
TransparencyGood
Sketch of NGC 40, a planetary nebula in the constellation Cepheus as viewed under suburban light polluted skies. You'll notice the very faint nebula around a central dim star, at least how I saw it from suburban Pacific Northwest skies.
Sketch of NGC 40. You’ll notice the very faint nebula around a central dim star, at least how I saw it from suburban Pacific Northwest Skies.

I almost left Cepheus behind with my observations this week, until I realized I missed NGC 40. I swept the telescope to the spot. I moved the scope slightly left and right, and in doing so, noticed a very faint smudge moving with it. I am also able to see the central star with averted vision.

Alas, I can confirm I have NGC 40 on my site. I didn’t believe I would be able to see this planetary with its dim magnitude, but I can see it—oh so faint on this very cold night hovering around freezing. I believe I can make out the wisp of nebula due to the stable upper atmosphere and clarity, something not always available in our Pacific Northwest skies.

Key Stats

ConstellationCepheus
Best ViewingAutumn
Visual Magnitude+10.6
Absolute Magnitude+.98
Distance from Earth2,700 ly
Diameter.5 ly
Apparent Size.6 x .6 arcmin
Milky Way LocationOrion Spur
My Viewing GradeC+

Sources and Notes

Banner photo credited to the National Optical-Infrared Astronomy Research Laboratory (NOIRLab). This file is licensed under the Creative Commons Attribution 4.0 International license. Full information is at Wikimedia here.

1 “NGC 40.” Wikipedia, Wikimedia Foundation, 19 July 2022, https://en.wikipedia.org/wiki/NGC_40.

Sketch by Wayne McGraw

AKA: Caldwell 2, C2, ARO 1, Bow Tie

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