
Cosmic Challenge: The Orion Galaxy
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Cosmic Challenge:The Orion GalaxyFebruary 2018Phil Harrington
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Target |
Type |
RA |
DEC |
Constellation |
Magnitude |
Size |
NGC 1924 |
Galaxy |
05 28 01.9 |
-05 18 37 |
Orion |
13 |
1.5'x1.1' |
You've heard of the Andromeda Galaxy and the Orion Nebula, but how about the Orion Galaxy? Probably not. But would you believe the New General Catalog lists 21 galaxies in Orion, and the Index Catalog adds another 9? That's a pretty respectable tally. Of those 30 Orion galaxies, I find this month's challenge particularly intriguing because it lies so close to everyone's favorite winter deep-sky object, M42. Yet, I am sure that very few observers have seen it.
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Above: Winter star map. Credit: Map adapted from Star Watch by Phil Harrington |
Above: Finder chart for this month's Cosmic Challenge. Credit: Chart adapted from Cosmic
Challenge by Phil Harrington |
NGC
Finding NGC 1924 is easy enough by starting at M42 and scanning due west. Some 1½° into your scan, you will come to a diagonal path of three 8th-and 9th-magnitude field stars oriented northwest-southeast from one another. NGC 1924 lies along the path, like a distant galactic steppingstone equally spaced between two of those Milky Way suns.
When summarizing its appearance for his New General Catalog, John Dreyer described it as "very faint, pretty large, irregularly round, stars nearby." My 8-inch (20.3cm) Newtonian shows NGC 1924 as a faint, oval disk accented by a stellar nucleus. It lies between two 8th-magnitude stars set amidst a sparkling field of fainter stardust.
Larger apertures bring out additional subtle details. Through my 18-inch (45.7cm) reflector, the galaxy reveals a brighter outer edge and a star-like central core, closely mimicking the look of a planetary nebula. Add in the spectacular surroundings and how they add a faux-3D effect, and the beauty of this little treasure really comes through. It's a challenge that you are sure to return to time and again as you further explore its more affluent neighbor.
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Above: NGC 1924 as sketched through the author's 8-inch (20.3cm) reflector. |
And what of the remaining NGC and IC galaxies within Orion? Here's the list.
Designation |
Coordinates RA h m s Dec ° ' " |
Magnitude |
Size |
IC 392 |
RA 04 46 25.8 Dec +03 30 20 |
13 |
1.4'x0.9' |
NGC 1661 |
RA 04 47 07.7 Dec -02 03 18 |
13 |
1.4’x0.9’ |
IC 395 |
RA 04 49 34.0 Dec +00 15 10 |
13 |
1.3’x1.0’ |
NGC 1670 |
RA 04 49 42.6 Dec -02 45 36 |
13 |
1.3’x0.7’ |
NGC 1678 |
RA 04 51 35.4 Dec -02 37 22 |
13 |
1.1’x0.8’ |
NGC 1682 |
RA 04 52 19.7 Dec -03 06 19 |
14 |
0.9’x0.9’ |
NGC 1683 |
RA 04 52 17.5 Dec -03 01 27 |
15 |
1.0’x0.4’ |
NGC 1684 |
RA 04 52 31.1 Dec -03 06 20 |
12 |
2.2’x1.7’ |
NGC 1685 |
RA 04 52 34.2 Dec -02 56 59 |
14 |
1.3’x0.9’ |
NGC 1690 |
RA 04 54 19.3 Dec +01 38 26 |
14 |
1.0’x1.0’ |
NGC 1691 |
RA 04 54 38.3 Dec +03 16 04 |
12 |
2.3’x1.8’ |
NGC 1709 |
RA 04 58 44.1 Dec -00 28 42 |
14 |
1.0’x0.7’ |
NGC 1713 |
RA 04 58 54.6 Dec -00 29 21 |
13 |
2.7’x1.8’ |
NGC 1719 |
RA 04 59 34.5 Dec -00 15 38 |
14 |
1.1’x0.3’ |
NGC 1729 |
RA 05 00 15.6 Dec -03 21 11 |
13 |
1.7’x1.4’ |
IC 2112 |
RA 05 00 30.2 Dec +04 23 11 |
14 |
0.5'x0.2' |
NGC 1740 |
RA 05 01 54.7 Dec -03 17 45 |
13 |
1.5’x1.2’ |
NGC 1753 |
RA 05 02 32.2 Dec -03 20 41 |
15 |
1.4’x0.6’ |
NGC 1762 |
RA 05 03 37.0 Dec +01 34 24 |
13 |
1.7’x1.1’ |
NGC 1819 |
RA 05 11 46.0 Dec +05 12 03 |
13 |
1.3’x1.0’ |
IC 404 |
RA 05 13 19.6 Dec +09 45 1 |
15 |
0.8'x0.6' |
NGC 1843 |
RA 05 14 06.1 Dec -10 37 36 |
13 |
2.1’x1.7’ |
IC 409 |
RA 05 19 33.7 Dec +03 19 04 |
14 |
1.3'x1.0' |
NGC 1875 |
RA 05 21 45.7 Dec +06 41 20 |
14 |
0.8’x0.7’ |
IC 414 |
RA 05 21 55.0 Dec +03 20 31 |
14 |
0.7'x0.4' |
IC 412 |
RA 05 21 56.8 Dec +03 29 10 |
14 |
1.4'x0.7' |
IC 413 |
RA 05 21 58.8 Dec +03 28 55 |
14 |
1.0’x1.0’ |
NGC 1924 |
RA 05 28 01.9 Dec -05 18 37 |
13 |
1.5'x1.1' |
IC 421 |
RA 05 32 08.5 Dec -07 55 05 |
14 |
3.3'x3.2' |
NGC 2110 |
RA 05 52 11.2 Dec -07 27 23 |
13 |
1.7’x1.2’ |
NGC 2119 |
RA 05 57 26.9 Dec +11 56 56 |
14 |
1.2’x1.0’ |
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Above: Orion's NGC and IC galaxies |
Notice from the chart above how most are clustered along the constellation's west-southwest border. That's not surprising, since that area is farthest from the obscuring dust clouds that permeate Orion. Further west, the river Eridanus overflows its banks with a flood of faint galaxies.
Be aware that many of Orion's galaxies are below the cutoff threshold of this column's self-imposed aperture class. But give them a go anyway.
I'd especially draw your attention to two galaxy groups. The first is a trio formed by of IC 412, 413, and 414, with a fourth, IC 409, waiting in the wings. You'll find them 3° south-southwest of Bellatrix [Gamma (γ) Orionis].
The second group is a tight pact in the constellation's southwestern corner. NGC 1682, 1683, 1684, and 1685 are so closely spaced that at the chart's scale here, they nearly overlap one another. Notice that the brightest of the four is 12th magnitude, with the others plummeting as low as 15th magnitude. That's a tough test for even the largest amateur telescopes.
Be sure to share your results with the rest of us by posting in this article's discussion forum.
Have a favorite challenge object of
your own? I'd love to hear about it, as well as how you did with this
month's test. Contact me through my web site or post to this
month's discussion forum.
Until next month, remember that half of the fun is the thrill of the
chase. Game on!
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About the Author: |
Phil Harrington's Cosmic Challenge is copyright 2018 by Philip S. Harrington. All rights reserved. No reproduction, in whole or in part, beyond single copies for use by an individual, is permitted without written permission of the copyright holder. |
- rolo and okiestarman56 like this
12 Comments
Thank you, Phil. I never think to scan over that way.
Hey, that's a great article Phil. Definitely enough there to get me out on a clear cold night to try and do an Orion galaxy sweep. Just like trading cards when I was a kid...I want to collect 'em all. As always, most of your observing reports are unusual in the sense that they cover many things I've never seen before and I do appreciate that. Thanks!
Very cool, Phil! I look forward to exploring those. Thanks!
Though I have your book, I've never went for this one. If these lake effect clouds go away when the moon's not up, I'll give it a try with my 7" reflector.
Dave Mitsky
Thanx, Phil; I'll haul that list out to the scopes. Nice and convenient all in that one piece of sky. Galaxies are all over the place, even where we generally don't think of looking for them. Tom
I wasn't crazy!!!
Last year while scanning Orion at a dark site, I noticed a smudge there .. I had to use averted vision, but there was something ... I mentioned that to some fellow guys, they gave me the "you just got crazy" eye...
NOW I know what I was looking at.
Phew!!!
From now, on, I can re-see that object (NGC1924) with total confidence ...
I shared the article with another CN member and we are going to have a ball at out next star party in a Bortle 3 sky. I have already found NGC 1924 with my 8SE and I will be using my CPC 1100 at the star party along with a AT 130EDT refractor.... This is going to be nice
Yep, looking at "that thing in Orion, at its west side" showed me my (averted and technique) vision has improved a lot since I started with my first telescope
Enjoy the SP!!!
I m signing up for RTMC in May, like Woodstock ... but with telescopes
I took a single 8 minute exposure of ngc 1924 with my 10" lx200 classic, and you guys have a lot better eyes then I do. What a faint target! You have my respect.
Phil:
Thanks for the heads up an NGC1924. I'd never seen it before.
While i was looking at Sky Safari to locate 1924, I noticed a small group of galaxies about 5 degrees at 300 degrees from 1924, PGC 16893, PGC16895 and UGC102. They're listed at magnitude 14.5-14.8. My skies aren't the darkest to the south, there's a prison across the border in Mexico but i was able see them in the 22 inch.
Now you've got me interested, I'll be looking for more..
Jon
There was a hole in the clouds in upstate NY last night, so I gave the challenge a try with my 8"reflector. I was unsuccessful, but sure enjoyed the effort! I'll keep trying, and when I get another hole in the clouds I may try to filter some of the sky glow to see if that helps.