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Abell 426     "Perseus Galaxy Cluster"


        created: 12-03-2023.             revised: 12-28-2023.

Hello!

Galaxy Clusters - What are they? Galaxies are large systems of stars and interstellar matter, typically containing from several million to several trillion stars. They run in size from a few 10's of thousands to several 100,000 light years in size, and are separated from other galaxies by millions of light years. Some galaxies are isolated "island universes" which float lonely through an otherwise empty region of the universe.
But the distribution of matter in the Universe is not uniform. This nonuniformity of interstellar matter causes groups of galaxies, which are the largest gravitationally bound structures in the universe, to form.
Galaxy clusters run anywhere from a few dozens of galaxies up to large clusters consisting of hundreds or even several thousands of galaxies.

         

American astrophysicist George Abell, (1927 - 1983), graduated from from the California Institute of Technology.
(B.S. in 1951, M.S. in 1952, and Ph.D. in 1957.)

Using the Palomar 48-inch Schmidt telescope, Abell compiled a catalog of clusters of galaxies, (2,712), which was first published in 1958 titled "The Distribution of Rich Clusters of Galaxies". An expanded version, published in 1989, of an additional 1,361 galaxy clusters, (in collaboration with astronomers Harold Corwin and Ronald Olowin), covering the southern hemisphere, brought the catalog up to 4,073 total galaxy clusters. Abell's qualifications for a galaxy cluster to be included in the catalog were the following four criteria:

Richness: A galaxy cluster must have a minimum population of 50 members within a two magnitude range of the 3rd-brightest galaxy cluster member. These are then divided into six "richness groups"
Group 0: 30 to 49 galaxies
Group 1: 50 to 79 galaxies
Group 2: 80 to 129 galaxies
Group 3: 130 to 199 galaxies
Group 4: 200 to 299 galaxies
Group 5: greater than 299 galaxies
(the average Abell galaxy cluster contains 64 individual members)

Compactness: A cluster must be sufficiently compact that at least fifty or more of the cluster members must lie within a radius of about 2 megaparsecs from the clusters center.

Distance: A catalog member cluster should have a redshift of between 0.02 and 0.2, corresponding to distances of between 85 and 850 Megaparsec (Mpc). As redsfit distance calculation improved over time, Abell divided the galaxy clusters into seven "distance groups" according to the magnitudes of their tenth-brightest galaxy member:
Group 1: mag 13.3 to 14.0
Group 2: mag 14.1 to 14.8
Group 3: mag 14.9 to 15.6
Group 4: mag 15.7 to 16.4
Group 5: mag 16.5 to 17.2
Group 6: mag 17.3 to 18.0
Group 7: mag > 18.0

Galactic latitude: In general, regions close to the galactic plane of the Milky Way were to be excluded from the study due to the interstellar obscuration by the Milky Way's spiral arms made it difficult to positively identify galaxy clusters.


Abell's catalog is recognized as an excellent compilation of galaxy clusters for the observer with access to large telescopes and dark skies. While several of the clusters contain one or more relatively bright NGC or IC galaxies, the majority of the catalog are galaxy clusters of faint PGC, UGC, or MCG galaxies. Many of the groups, (officially designated as 'ACO'), have at least one member plotted in several popular printed star atlases such as 'Uranometra 2000' or the 'Millennium Star Atlas".
For the most part, they can be difficult to observe, but broadband filters, such as the L-Pro, can be a big help, allowing the galaxies to 'pop' from the star field.


Amatuer Astronomer Alvin Huey has a great Abell Galaxy Cluster guidebook available on his website faintfuzzies:

The free PDF download contains finder charts along with DSS images and visual observations of select Abell Galaxy Clusters.
You can either keep the catalog on your favorite PC device or take it to a printer and get a bound booklet made.



Below is my personal observation list of the 'Abell Galaxy Cluster catalog'.

So far, I have observed 12 Abell Galaxy Clusters.
All of my EAA Observations were taken using a ZWO ASI294MC camera with ROI=2072x1410 and a L-Pro broadband filter, and 8" SCT optical tube on a Gem.  
Each image is generally centered on the brightest galaxy near the cluster's core and has minimal processing applied to it: image converted to 'negative' to help bring out the tiny galaxies, and resized to have the same general field size across images. Most of these are faint, even with long exposures.
To match my image with Alvin Huey's book, you'll need to rotate the book either to the right or left, depending on which side of the meridian the cluster was on when it was EAA observed.


Index:

Abell Object (ACO) NGC/IC or brightest member +Mag Constellation Name
Abell 154: IC1634 +15.7 Pisces
Abell 262: NGC708 +13.7 Andromeda
Abell 347: NGC910 +13.8 Andromeda
Abell 376: UGC2232 +15.4 Perseus
Abell 407: UGC3274 +14.7 Perseus
Abell 426: NGC1275 +12.6 Perseus "Perseus Cluster"
Abell 539: UGC3274 +14.4 Orion
Abell 592: IC2380 +15.0 Canis Minor
Abell 671: IC2380 +14.9 Cancer
Abell 2199: NGC6166 +12.8 Hercules
Abell 2634: NGC7720 +12.6 Pegasus "Pegasus Cluster"
Abell 4038: IC5358 +14.7 Sculptor


Abell Galaxy Cluster Observations:



Abell 154 (galaxy cluster) - 11/12/2023 - 8" SCT f6.3, Atlas Gem, ASI294MC @ 180 seconds for 30 minutes (L-Pro filter)
Cluster Members: IC1634, IC1635, PGC4253, PGC4193, PGC4209, PGC73760, PGC73748,
PGC73743, PGC73761, PGC73764, PGC73766, PGC1535574, PGC1539023,
MAC0110+1745A, MAC0110+1745B, MAC0110+1736, MAC0111+1738B, MAC0111+1741B



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Abell 262 (galaxy cluster) - 11/12/2023 - 8" SCT f6.3, Atlas Gem, ASI294MC @ 180 seconds for 30 minutes (L-Pro filter)
Cluster Members: NGC708, NGC700, NGC703, NGC704, NGC705, NGC709, NGC710,
PGC6974, UGC1319, CGCG522-30, MCG+6-5-24



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Abell 347 (galaxy cluster) - 11/12/2023 - 8" SCT f6.3, Atlas Gem, ASI294MC @ 180 seconds for 30 minutes (L-Pro filter)
Cluster Members: NGC910, NGC911, NGC912, UGC1866, UGC1858, PGC2188914, MAC0225+4150, MAC0025+4146



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Abell 376 (galaxy cluster) - 12/15/2023 - 8" SCT f6.3, Atlas Gem, ASI294MC @ 180 seconds for 30 minutes (L-Pro filter)
Cluster Members: UGC2232, MAC0245+3639, MAC0245+3641B, MAC0245+2642A, MAC0245+3642B, MAC0245+3647,
MAC0245+3648A, MAC0245+3650, MAC0245+3651B, MAC0245+3651C, MAC0246+3649



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Abell 407 (galaxy cluster) - 12/15/2023 - 8" SCT f6.3, Atlas Gem, ASI294MC @ 180 seconds for 30 minutes (L-Pro filter)
Cluster Members: UGC2232, UGC2491, UGC2493, MAC0301+3538, MAC0301+3540, MAC0301+3554B,
MAC0301+3555A, MAC0301+3558B, MAC0302+3540



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Abell 426 (galaxy cluster) - 11/13/2023 - 8" SCT f6.3, Atlas Gem, ASI294MC @ 180 seconds for 30 minutes (L-Pro filter)
Cluster Members: NCG1275, NGC1272, NGC1270, NGC1271, NGC1273, NGC1277,
NGC1278, NGC1281, NGC1282, NGC1283, IC1907



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Abell 539 (galaxy cluster) - 12/15/2023 - 8" SCT f6.3, Atlas Gem, ASI294MC @ 180 seconds for 30 minutes (L-Pro filter)
Cluster Members: UGC3274, UGC3275, MAC0516+0619, MAC0516+0620, MAC0516+0622, MAC0516+0623,
MAC0516+0626A, MAC0516+0627B, MAC0516+0627C, MAC0516+0630B, MAC0516+0630C



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Abell 592 (galaxy cluster) - 12/14/2023 - 8" SCT f6.3, Atlas Gem, ASI294MC @ 180 seconds for 30 minutes (L-Pro filter)
Cluster Members: NGC2433, MAC0742+0912, MAC0742+0916, MAC0742+0919A, MAC0742+0921, MAC0742+0922A, MAC0742+0925B



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Abell 671 (galaxy cluster) - 12/14/2023 - 8" SCT f6.3, Atlas Gem, ASI294MC @ 180 seconds for 30 minutes (L-Pro filter)
Cluster Members: IC2380, IC2378, MAC0828+3024A, MAC0828+3024B, MAC0828+3026, CGCG149-35, CGCG149-27, CGCG149-28



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Abell 2199 (galaxy cluster) - 11/11/2023 - 8" SCT f6.3, Atlas Gem, ASI294MC @ 180 seconds for 30 minutes (L-Pro filter)
Cluster Members: NGC6166, NGC6166C, MCG+7-34-50, MCG+7-34-48, PGC58277, PGC58278, PGC58279
PGC 58325, PGC58262, PGC2149914, PGC2153801, PGC2154233



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Abell 2634 (galaxy cluster) - 11/12/2023 - 8" SCT f6.3, Atlas Gem, ASI294MC @ 180 seconds for 30 minutes (L-Pro filter)
Cluster Members: NGC7720, NGC7726, IC5341, IC5342, PGC71987, PGC85577,
PGC71977, PGC85559, PGC71976, PGC71994, PGC72000



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Abell 4038 (galaxy cluster) - 11/12/2023 - 8" SCT f6.3, Atlas Gem, ASI294MC @ 180 seconds for 15 minutes (L-Pro filter)
Cluster Members: IC5358, IC5353, IC5354, PGC85756, PGC85759, PGC72451, PGC72436,
PGC72393, PGC85750, PGC85758, PGC72403, PGC747116



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Hope you enjoyed the visit. Come again soon!
Larry McHenry,   Pittsburgh, PA. USA

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