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View Full Version : Object of the Week, February 3, 2019 - NGC 2392, the Inuit Nebula



Howard B
February 4th, 2019, 04:26 AM
Object of the Week, February 3, 2019

NGC 2392, the Inuit Nebula

Planetary Nebula

Gemini
RA 07 29 10
DEC +20 54 42
Magnitude 10.1 (v)
Size: 48” x 48”
Discovered by William Herschel, 1787

I picked NGC 2392 as this weeks OOTW for two reasons – first because it hasn’t been the subject of a previous OOTW (as far as I can tell) and second because of how it was conspicuously not referred to as the Eskimo Nebula, its well-known nickname, in Sue French’s’ Deep Sky Wonders article in the March edition of Sky & Telescope magazine. An incredibly detailed sketch by Serge Vieillard is featured in the article.

It was only called out as NGC 2392, but was described in terms that made it obvious how it got its nickname: "On some images, the brightness variations near the central star resemble facial features, while the fringe looks like the fur of a parka's hood." This was also the case in Steve Gottlieb’s S&T article a few years ago when he wrote about this famous planetary nebula.

The Inuit People of the Canadian and Greenland arctic consider “Eskimo” a pejorative term (see https://en.wikipedia.org/wiki/Eskimo) - an excellent reason to stop calling NGC 2392 the Eskimo Nebula, and good for Steve, Sue French and S&T for stopping the practice. Because the Inuit people prefer to be called Inuit, I’m going with that rather than ignore the nickname altogether. NGC 2392 is too big, bright and well-known to lose a distinctive nickname. In my opinion, calling it the Inuit Nebula going forward is both respectful and logical.

What do you think?

Visually, the Inuit Nebula can be a stunning sight in even a modest size telescope, but the bigger the better. I’ll present two observations here, one with my 28-inch scope and one with the 90-inch Bok telescope on Kitt Peak. My observing notes were made before I was aware of the Inuit’s objection to the term Eskimo, so I’ve substituted the name Inuit here.

28-inch
“Holy smoke, this is by far the finest view of the Inuit ever – Chuck (Dethloff) could hardly believe it too! The sketch was made at 654x and the blue-green color was still evident, especially with my right eye. The OIII and UHC filters made the nebula brighter but brought out no additional details.” February 2005

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90-inch
“Now this is some nice eye candy! The sketch shows the basic features – the gap in the inner annulus, which Dan (Gray) has dubbed “the Mouth”, the dark perimeter exterior to that annulus, the slightly off-center central star, and a dim thin annulus halfway to the outer perimeter with a couple of condensations. The inner annulus has a distinctive turquoise color, but unsaturated. There’s a slight hint of the same color throughout the entire planetary nebula – beautiful! 660x, 21.50 SQM.” April 2010

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I’ve always had difficulty star hopping to the Inuit Nebula, and it usually takes me more than one attempt to get in the eyepiece – anyone else have that experience? It’s always worth the effort though, even in lousy seeing, because the color is so rich at low power.

"Give it a go and let us know"

Ciel Extreme
February 4th, 2019, 11:45 AM
Observation from two years ago, the observing details with the sketch:

“This is a bright, large and detailed object, very well seen at high magnification. The central star is bright (though unseen with an OIII filter) and immediately surrounded by a dark zone. A bright, donut-shaped inner ring, very well defined and about 13" in diameter is next and then the large, broad outer disc is seen; a bright, round and heavily mottled object, pretty well defined, though the edges are a little soft and the disc appears a little fainter on the eastern side. Bright field star to the north.”



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KidOrion
February 4th, 2019, 06:46 PM
But what if it's Yupik?

Raul Leon
February 4th, 2019, 11:20 PM
Hi here's my observation from 9/26/2008, ngc 2392 planetary nebula in Gemini; magnitude:9.2 ; size:48" ; large and bright this object takes magnification well; structured shells visible: bright central star observed; I used a a 7mm Nagler at 226x magnification with my 14.5 Starstructure Dob f/4.3 ; no filter used 3422

Ivan Maly
February 5th, 2019, 01:41 AM
"Bright central star. Bluish-green fuzzy annulus with a persistent impression of radial texture." 2019-01-13, 20", 155x, SQM 21.7.

As to the name, Kid Orion said it best.

Bertrand Laville
February 5th, 2019, 06:53 AM
Hi All,

Just a close up of a larger field that you could link at
http://www.deepsky-drawings.com/ngc-2392/dsdlang/fr
with a very very detailed report, if you're interested on.

You can also have a look at the drawing of Serge Vieillard, a friend of mine, at:
http://www.deepsky-drawings.com/ngc-2392-t620635-2-obs/dsdlang/fr

Clear skies
Bertrand
http://www.deepsky-drawings.com


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kisspeter
February 5th, 2019, 09:50 AM
Amazing drawings above!
I can only contribute a very old and bad drawing from 2000 with a 4" (169x). Obviously I couldn't see many details with such a small scope. "Ny" is West.
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Concerning the name, sometimes I find these nicknames pretty annoying. They don't always help: a nickname might be simpler than a catalog number but it's not always clear what object it refers to (at least to me). Especially with recently made up nicknames.

Uwe Glahn
February 6th, 2019, 06:55 PM
Wow Howard, NGC 2392 trough a 90-inch must be an incredible experience.

The "mouth" you refer to is called "bridge" here in Germany. I chase this detail over years until I had success.

My notes about the "mouth" were as follows:
16", 515x, NELM 7m0+, Seeing I
after several failed attempts finally visible as a black hole within the pointy N end of the inner shell.

sketch (without bridge): 16", 600x, [OIII], NELM 6m5+, Seeing II-III
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18", 740x, NELM 7m0+, Seeing I
very difficult detail, bridge is visible as a second peak within the shell; gap only little darker

27", 837x, NELM 7m0+, Seeing I
spectacular view under best seeing conditions; bridge directly and easy to see; gap between bridge and northern shell relative large

27", 586x, NELM 6m5+, Seeing III
under modest seeing bridge difficult to see despite the large aperture; no steady visible as a hole within the pointy and filled northern shell

48", 814x, NELM 7m0+, Seeing III
even under no perfect seeing conditions the bridge itself and the dark hole easy to see

>I’ve always had difficulty star hopping to the Inuit Nebula, and it usually takes me more >than one attempt to get in the eyepiece – anyone else have that experience?

Ähm...NO, NEVER...yes