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Cosmic Challenge: NGC 2419


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Cosmic Challenge:

NGC 2419

March 2018

Phil Harrington

This month's suggested aperture range:

Giant Binoculars

 

3- to 5-inch (75-127mm) telescopes

Target

Type

RA

DEC

Constellation

Magnitude

Size

NGC 2419

Globular cluster

07 38.1

+38 52.9

Lynx

10.3

4.6'

 

Probably known better by its nickname the "Intergalactic Tramp" bestowed by Harlow Shapley in 1944, NGC 2419 is unusual among winter's deep-sky objects for many reasons. First, it lies within the nondescript constellation of Lynx, a nearly starless span between the Gemini twins and the leading paw of Ursa Major.

Above: Winter star map showing the location of this month's Cosmic Challenge.

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
Click on the chart to open a printable PDF version in a new window

Next, the nature of the object, a globular cluster, seems quite out of place in a region dominated by distant galaxies. Aren't globular clusters supposed to swarm around the center of the Milky Way? That's certainly where we find most, scattered throughout Sagittarius and neighboring Ophiuchus, Scorpius, and other nearby summer constellations. The fact that NGC 2419 is so far from the galactic core led many astronomers in the early 20th century to conclude, albeit erroneously, that is an independent system. The "Intergalactic Tramp" epithet echoes that incorrect assumption.  (I should point out that when Shapley used the word "tramp" in 1944 to describe NGC 2419, its connotation was quite different than how many use the same word today. Shapley likely used the term to signify NGC 2419's slow, somewhat aimless meandering, like a hobo, rather than a comment on its lack of morality!)


Like the other 150 or so globulars in the Milky Way's family, NGC 2419 does indeed orbit the center of our galaxy. Its orbital path, however, is quite unique among globulars. Unlike most other globulars, which hug the core, NGC 2419 follows a wide, eccentric track that takes an estimated three billion years to complete. At the present time, NGC 2419 is projected to be between 275,000 and 300,000 light years away from the solar system and about the same distance away from the galactic center. That's farther away than two of our galaxy's dwarf galaxies, the Large and Small Magellanic Clouds.


Although the constellation Lynx is difficult to spot, locating NGC 2419 is not as tough as it might appear at first thanks to its proximity to Castor [Alpha (α) Geminorum]. Center Castor in your finderscope and then slowly scan about half a field northward to the 5th-magnitude stars Omicron (ο) and 70 Geminorum. Hop another half field northward and you'll come to another, fainter pair of stars (6th-magnitude SAO 60257 and 7th-magnitude SAO 60234) oriented east-west. Time to switch to your telescope. You should see another, tighter pair of 7th-magnitude stars (SAO 60229, a fine double star in its own right, and SAO 60232) just to the north. All four stars should fit into the same field of your widest-field eyepiece. Now, swap eyepieces to medium magnification, say 100x or so, and take another look. Can you spot a very faint, diffuse blur just to the east of those two 7th-mag stars? If so, you've nabbed NGC 2419.


Above: NGC 2419 as sketched through the author's 4-inch refractor.

 

NGC 2419 glows dimly at magnitude 10.3 and spans about 4 arc-minutes. Since none of its stars shine brighter than 17th magnitude, NGC 2419 appears pretty much the same when viewed through all but the very largest backyard telescopes -- faint and fuzzy with just the slightest suggestion of a brighter central core. To catch any hint of NGC 2419, however, requires a dark sky, so wait for one of those special late-winter nights when the Moon is down and the air is dry.


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!




About the Author:

Phil Harrington writes the monthly Binocular Universe column in Astronomy magazine and is the author of 9 books on astronomy.  Visit his web site at www.philharrington.net to learn more.

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.

 


  • stevek, okiestarman56 and Sasa like this


8 Comments

Thanks Phil for the excellent sketch, star hopping directions and write-up for NGC 2419, an object I haven't viewed yet. Brad

It looks like this is indeed a really tough challenge.

Photo
Astrojensen
Mar 04 2018 09:35 AM

It looks like this is indeed a really tough challenge.

Nah, not really. It depends heavily on the sky, though. I've seen it in a 2" f/17 refractor from a dark sky site without much trouble, and also in a 60mm finderscope at just 10x. At that low power, it really is quite challenging, but in the 2" at 30x, it's pretty straightforward. 

 

 

Clear skies!
Thomas, Denmark

YIKES! This one's gona be interesting... My 36-inch scope goes operational late April (hope!). So I will hope to be able to see 2419 maybe, just maybe... as something more than a fuzzy? Nice and high for us Northerners, too! Thanks!  Tom

Photo
Astrojensen
Mar 04 2018 03:51 PM

YIKES! This one's gona be interesting... My 36-inch scope goes operational late April (hope!). So I will hope to be able to see 2419 maybe, just maybe... as something more than a fuzzy? Nice and high for us Northerners, too! Thanks!  Tom

With a 36", you should be able to resolve some stars - or perhaps many. On the very best nights, I can see a hint of mottling in my 12" at 200x, though this might be a sprinkling of foreground stars in front of the cluster or tiny groups of unresolved stars. 

 

 

Clear skies!
Thomas, Denmark 

 

YIKES! This one's gona be interesting... My 36-inch scope goes operational late April (hope!). So I will hope to be able to see 2419 maybe, just maybe... as something more than a fuzzy? Nice and high for us Northerners, too! Thanks!  Tom

With a 36", you should be able to resolve some stars - or perhaps many. On the very best nights, I can see a hint of mottling in my 12" at 200x, though this might be a sprinkling of foreground stars in front of the cluster or tiny groups of unresolved stars. 

 

 

Clear skies!
Thomas, Denmark 

 

Yes, indeed. I'm all excited about the 36 and this will be a great test of its capability. Hoping the views will be... decadent!  [luxuriously, lavishly self-indulgent].  Tom

    • Astrojensen likes this

Thanks Phil, for the interesting writeup and the challenge. I've only see this DSO one time, on April 21, 2011 in a dark sky before Moon rise, seeing fair to good. 

 

Celestron-11, f/6.3, 160X (11mm Nagler, T6)

 

Here's the note in my observing record:

Remote globular cluster in Lynx; mag. 10, ~5' dia., at end of line with 2 roughly 4th mag. stars; with close scrutiny can see around 1/2 dozen very faint stars; brighter glow in center

 

For the last 10 years I've been using a go-to mount. But I don't feel bad about that after using star atlas and finder 'scope for the previous 40+ years. My old neck and back appreciates the hi-tech help.

    • Jon Isaacs likes this

Phil:

 

Thanks for the write up and for the challenge . They always add something extra special to an evening. 

 

This has not been a good month cloud-wise so my only chance at observing 2419 has been with the moon nearly full from an otherwise dark site. I was able to detect it with my 12.5 inch under the full moon,  i figure I should be able to see it from red zone backyard on a moonless night. 

 

The saga will continue. 

 

Jon



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