
Cosmic Challenge: Beehive Galaxies
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Cosmic Challenge: Beehive Galaxies
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Target |
Type |
RA |
DEC |
Constellation |
Mag |
Span |
Beehive |
Galaxy |
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.
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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
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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-
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
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!
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the Author: |
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. |
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