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Cosmic Challenge: Beehive Galaxies


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Cosmic Challenge: Beehive Galaxies

 

March 2022

Phil Harrington

This month's suggested aperture range:

15-inch (38 cm) and larger telescopes

 

 

 

Target

Type

RA

DEC

Constellation

Mag

Span

Beehive
Galaxies

Galaxy
collection

08h 40.4m

+19° 40'

Cancer

varies

66'

 

One of my favorite binocular open clusters in the entire sky is M44, the Beehive Cluster or Praesape, in Cancer the Crab.  It's a wonderful target through just about any pair of binoculars.  Even the smallest, cheapest pair will show a rich vault of stars.  Nine of the brightest stars near the center of the cluster form a distinctive V asterism that is sometimes called the Heart of the Crab.  The Heart points toward the southwest and always attracts attention.

 

Hidden among the stars of M44 are no fewer than eight distant galaxies.  Until 1987, most of us knew nothing of them.  That was the year when the Uranometria 2000.0 star atlas was published.  It showed the sky to a depth never before captured in a convenient star atlas format, and immediately shed light on thousands of objects that no amateurs, except possibly for a few extreme deep-sky hunters, even knew existed.

Above: Evening 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

 

The biggest problem in spotting the galaxies beyond the Beehive is not their dimness, although that is clearly a factor.  That dilemma pales compared to the predicament caused by the cluster's stars.  Those stars shine as brightly as 6th magnitude, so they easily out-dazzle these puny 14th- and 15th-magnitude galaxies.  Although a 15-inch (38cm) or larger scope will be needed to see all of the galaxies listed in the table below, the brightest two or three can be captured with a 10-inch (25cm), perhaps even smaller, under dark skies.

 

Beehive Galaxies

Target

RA

DEC

Magnitude

Size

NGC 2624

08 38.2

+19 43.6

14.6

0.7'x0.5'

NGC 2625

08 38.4

+19 43.0

14.5p

0.4'

CGCG 89-56

08 38.4

+19 35.8

15.2

0.7'x0.2'

CGCG 89-62

08 39.2

+19 28.9

15.6

0.4'

IC 2388

08 39.9

+19 38.7

15.7

0.5'x0.3'

UGC 4526

08 40.9

+19 21.3

14.8p

1.4'x0.2'

NGC 2637

08 41.2

+19 41.5

15.4

0.5'x0.4'

NGC 2643

08 41.9

+19 42.1

15.6

0.7'x0.4'

NGC 2647

08 42.7

+19 39.0

15.1

0.7'x0.6'

 

German-born astronomer Albert Marth discovered the first five background galaxies in 1864 while working as William Lassell's assistant at Lassell's observatory in Malta. Personally, I find NGC 2647 the easiest to spot. Look for it about 1' northeast of a 13th-magnitude star along the cluster's eastern flank. At 206x, my 18-inch (46cm) displays a faint, round glow no more than 20" across, as shown in the rendering below. I've never seen any hint of a central core, but others have noted a stellar nucleus, so be sure to check for yourself. The largest backyard telescopes might also pick up a pair of very faint stars to either side of the galaxy.

 

Above: Look carefully and you will see many faint fuzzies across this three-field view through the author's 18-inch (46cm) telescope. Click the image to get a closer look in a new tab.

 

Scan westward across the full breadth of M44 for NGC 2624, another galaxy bright enough to be seen in 10-inch (25cm) scopes.  Look for it 8' to the east of 8th-magnitude SAO 97973 at the cluster's western edge.  Through my 18-inch (46cm) at 206x, this tiny spiral galaxy appears as a faint, circular glow measuring perhaps 25" across and slightly brighter toward the center.  A very faint field star lies nearby to the southwest, while another galaxy, NGC 2625, is about 3' to the east-southeast.

NGC 2625, an elliptical galaxy, is smaller and fainter than its neighbor, but I can still make it out with direct vision in the 18-inch (46cm) at 206x.  Using averted vision, however, reveals a very faint star on the western edge of the galaxy -- don't confuse it for a supernova!  Interestingly, some catalogs list NGC 2625 as more than a magnitude fainter than NGC 2624.  My own experience, however, points to it being no more than half a magnitude dimmer, so take those numbers under advisement.

Moving southward, CGCG 89-56, a pair of close-set galaxies listed in the Catalog of Galaxies and Clusters of Galaxies by Fritz Zwicky, is visible as a very small, dim blur.  The Digital Sky Survey shows two small, edge-on spirals oriented east-west and north-south, but try as I might through my 18-inch (46cm) , I cannot resolve them.

Another member of Zwicky's catalog, CGCG 89-62, lies about 3' west-northwest of a pair of 10th- and 11th-magnitude stars set southwest of the Heart.  I have never been able to see it convincingly, despite being to see a 15th-magnitude star just 1' to its east.  Perhaps you will have better success.

IC 2388 is found 1.6' to the south of a 10th-magnitude star that marks the tip of an isosceles triangle near the Heart of the Crab.  Marth missed it that night in 1864, but it is visible through my 18-inch (46cm) under 5th-magnitude skies, so don't shy away from it just because it is not in the NGC.

Continuing eastward, we come to NGC 2637, a fairly easy catch because of its position comparatively far from any bright cluster stars.  The nearest bright stars are 42 Cancri, 7' to its west-northwest, and SAO 98043, 5' south-southeast.  Averted vision is still required to see this little system, but with patience, it should come through pretty clearly.

 

Finally, try to spot NGC 2643 about 1' northwest of an 11th-magnitude cluster star.  NGC 2643 is the toughest of the NGC galaxies here.  I can barely make it out through the 18-inch (46cm) at 206x by using averted vision, and then only as a very dim, very small smear no more than 15" across.

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 challenge.  Contact me through my website 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 2022 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.

 


  • okiestarman56, John O'Hara, CharLakeAstro and 3 others like this


7 Comments

Awesome, Phil!  I'll be trying this out the next clear night!  Just moved to darker skies with a 12.5" dob, and snagged 14th mag 2927 in Leo, so this couldn't be more perfectly timed.  Ready to try this!  Thanks for a cool puzzle.

    • PhilH likes this
Photo
Dave Mitsky
Mar 01 2022 01:24 PM

A fellow ASH member called the Heart of the Crab asterism the House many years ago and that's what I've always gone by.

    • Special Ed and PhilH like this

I last imaged this 1-9-22, with a C8, ASI183mm, and the original Fastar lens. The ASI183mm camera turned out to be a poor match for the Fastar lens, which was designed for smaller chips like the old ST-237 camera. Still got a lot of sky in the image even cropped.

 

M44:

 

Attached Image: Stack_5frames_158s_Beehive_M44.jpg

 

 

 

Also got quite a few of the Beehive Galaxies:

 

Attached Image: 6256193.jpg

 

 

Thanks for the Cosmic Challenge background information, very interesting as usual.

    • PhilH, eros312 and litesong like this

Going to see a lot of images of this--it's this month's target for Goofi's Imaging Challenge! 

    • PhilH likes this

Wasn't there an article in S&T years ago about these galaxies?  I remember being aware of them in the early 1980s.  While attending KU at that time I recall taking a plate of M44 with the 27-inch to pick out some of the galaxies. It seems at least two were on the plate, though it didn't cover the entire cluster.  In 1996 was I was able to pick out five of the galaxies with a 13.1-inch Coulter.  They were NGC 2624, NGC 2635, NGC 2647, IC 2388, and UGC 4526.

    • PhilH and litesong like this

As the month winds down, I looked to see if I had a better Beehive. I had imaged it 15 times since 2-5-21!  Most were pretty poor. But the most recent, although not well centered, was my best image. Practice, practice, practice... This is from 3-16-22 and was from my GSO 6", ASI533MC Pro, MPCC and UV/IR filter.  

 

 

 Attached Image: Stack_5frames_98s_Beehive.jpg

I remember being aware of them in the early 1980s.  While attending KU at that time I recall taking a plate of M44 with the 27-inch to pick out some of the galaxies. It seems at least two were on the plate, though it didn't cover the entire cluster.  In 1996 was I was able to pick out five of the galaxies with a 13.1-inch Coulter.  They were NGC 2624, NGC 2635, NGC 2647, IC 2388, and UGC 4526.

Cool!!!

From the 1988 NGC 2000 book by Roger Sinnott, in the 1990’s, I had transferred galaxy positions around M44 onto my SkyAtlas charts. Also a galaxy cluster appeared in my transfers, not quite 20arcminutes to the “westsouthwest” of M44.

Can you help me if my plots were very accurate? I think I have NGC 2624 on the west edge of M44 & NGC 2647 plotted east of M44.



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