ARP Galaxies

Stephan's Quintet Galaxy Group in Pegasus

Stephan’s Quintet can be found in the constellation Pegasus, the apparent magnitude of these galaxies hovers around 14.0, making this a tough object to capture in a smaller telescope. This group of galaxies was discovered by Edouard Stephan in 1877 at Marseille Observatory. Although referred to as a quintet, only four of the five galaxies are interacting with each other at a distance of about 300 million light years! NGC 7320 is actually much closer at a distance of “only” 40 million light years.
The members in the group include NGC 7320, NGC 7319, NGC 7318a, NGC 7318b, and NGC 7317. The group is also listed in the Arp catalog as ARP319.
Observation data (Epoch J2000)Constellation(s): PegasusRight ascension: 22h 35m 57.5sDeclination: +33° 57′ 36″Number of galaxies: 5
Tech Specs: Orion 8” RC Telescope, ZWO ASI2600MC camera running at 0F, 1 Hour and 55 Minutes using 60 second exposures, Celestron CGEM-DX pier mounted, ZWO EAF and ASIAir Pro, processed in PixInsight. Image Date: July 1, 2024. Location: The Dark Side Observatory (W59), Weatherly, PA, USA (Bortle Class 4).

Galaxy Arp 145 in the Constellation Andromeda

UGC 1840, also known as Arp 145, is a pair of interacting galaxies located 250 million light-years away from the Solar System in the Andromeda constellation. Made up of two galaxies, UGC 1840 NED01 (PGC 9060) and UGC 1840 NED02 (PGC 9062), the two galaxies had recently collided with each other in which the elliptical galaxy has penetrated through the spiral galaxy's nucleus leaving a hole in its middle, thus forming a ring galaxy. Both galaxies are listed as Arp 145 in the Atlas of Peculiar Galaxies which was created by Halton Arp. They fall under the category of objects that have emanating material and both classified as galaxies that have ring systems. (ref: Wikipedia)
Observation dataConstellation: AndromedaRight ascension: 02h 23m 08.4268sDeclination: +41° 22′ 20.031″Type: PeculiarSize: ~131,100 ly (40.20 kpc) (estimated)Notable features: Collisional ring galaxyOther designations: IRAS 02200+4108, 2MASX J02231142+4122047, Arp 145, MCG +07-06-002, PGC 9060 & 9062, CGCG 538-056, HFLLZOA F264, V Zw 229
Tech Specs: Orion 8” RC Telescope, ZWO ASI2600MC camera running at 0F, 162 x 60 second exposures, Celestron CGEM-DX pier mounted, ZWO EAF and ASIAir Pro, processed in PixInsight. Image Date: September 12, 2024. Location: The Dark Side Observatory (W59), Weatherly, PA, USA (Bortle Class 4).

Arp 278 - Interacting Spiral Galaxies in Pegasus

Arp 278 is a pair of interacting spiral galaxies in the constellation Pegasus. This image is a small clip from a large image and is overprocessed to bring out some details in the galaxies. You can see several areas of bright knots of star formation throughout both galaxies. The pair are listed in the NGC catalog as NGC7253 and NGC7253A.
Observation data (J2000 epoch)Constellation: PegasusRight ascension: 22h 19m 28.9sDeclination: 29° 23′ 30.0″Distance: 203.7 Mly (62.46 Mpc) & 200.4 Mly (61.43 Mpc)Apparent magnitude (V): 13.2 & 14.3Apparent size (V): 1.7' x 0.8' & 1.6' x 0.5'
Tech Specs: Orion 8” RC Telescope, ZWO ASI2600MC camera running at 0F, 162 x 60 second exposures, Celestron CGEM-DX pier mounted, ZWO EAF and ASIAir Pro, processed in PixInsight. Image Date: September 13, 2024. Location: The Dark Side Observatory (W59), Weatherly, PA, USA (Bortle Class 4).

NGC 507 Galaxy Group in Pisces (ARP 229)

The NGC 507 group is the single richest group of galaxies in Pisces containing 9 NGC galaxies brighter than 15th magnitude. There are also a number of galaxies listed in the IC here as well. NGC 508 is also listed in the Arp Catalog as Arp 229, if you look close you may be able to spot a concentric ring around the center of the galaxy.
Tech Specs: Orion 8” RC Telescope, ZWO ASI2600MC camera running at 0F, 191 x 60 second exposures, Celestron CGEM-DX pier mounted, ZWO EAF and ASIAir Pro, processed in PixInsight. Image Date: September 13, 2024. Location: The Dark Side Observatory (W59), Weatherly, PA, USA (Bortle Class 4).

Abell 2151 - Hercules Galaxy Cluster

Abell 2151 is a large cluster of galaxies (also known as the Hercules Galaxy Cluster) and is located about 500 million light years away and covers an area of 6 million light years with about 200 galaxies. It is part of the Hercules Supercluster, which is part of an even larger extragalactic structure simply known as the Great Wall. Four groupings of galaxies are included in the Arp Atlas, the most for any galaxy cluster. These include Arp 71 (NGC 6045), Arp 122 (NGC 6040), Arp 172 (IC 1178/81) and Arp 272 (NGC 6050/IC 1179).
Observation data (Epoch J2000)Constellation(s): HerculesRight ascension: 16h 05m 15.0sDeclination: +17° 44′ 55″Brightest member: NGC 6041
Tech Specs: Sky-Watcher Esprit 120ED Telescope, ZWO ASI2600MC camera running at 0F, 108x60 seconds guided exposures, Sky-Watcher EQ6R-Pro pier mounted, ZWO EAF and ASIAir Pro, processed in DSS and PixInsight. Image Date: May 18, 2023. Location: The Dark Side Observatory (W59), Weatherly, PA, USA (Bortle Class 4).

The Fireworks Galaxy and an Open Cluster

NGC 6946, sometimes referred to as the Fireworks Galaxy, is a face-on intermediate spiral galaxy with a small bright nucleus, whose location in the sky straddles the boundary between the northern constellations of Cepheus and Cygnus. Its distance from Earth is about 25.2 million light-years. NGC 6939 is an open cluster and is located 4,000 light-years from our solar system. This is a two panel mosaic image, each panel was 81 minutes of exposure time.
NGC 6946 also appears in Arps Atlas of Peculiar Galaxies as ARP 29. It was placed in the “Peculiar Galaxy” category since it has one spiral arm that is larger than the others.
Tech Specs: Sky-Watcher Esprit 120ED Telescope, ZWO ASI2600MC camera running at 0F, two panel, each panel 81x60 seconds guided exposures, Sky-Watcher EQ6R-Pro pier mounted, ZWO EAF and ASIAir Pro, processed in DSS and PixInsight. Image Date: May 26, 2023. Location: The Dark Side Observatory (W59), Weatherly, PA, USA (Bortle Class 4).

The Tadpole Galaxy - Arp 188

The Tadpole Galaxy, also known as UGC 10214 and Arp 188, is a disrupted barred spiral galaxy located 420 million light-years from Earth in the northern constellation Draco. Its most dramatic feature is a trail of stars about 280,000 light-years long. (Wikipedia) The Tadpole Galaxy is currently interacting with another galaxy and the tidal forces have created the 280,000 light-year tail.
Observation data (J2000 epoch)Constellation: DracoRight ascension: 16h 06m 03.9sDeclination: +55° 25′ 32″Distance: 420 MlyApparent magnitude (V): 14.4Apparent size (V): 3.6′ × 0.8′
Tech Specs: Orion 8" f/8 Ritchey-Chretien Astrograph Telescope, Celestron CGEM-DX pier mounted, ASI071MC-Pro, ZWO AAPlus, ZWO EAF, 180 x 60 seconds at -10C, processed using DeepSkyStacker and PixInsight. Image Date: April 13, 2023. Location: The Dark Side Observatory (W95), Weatherly, PA, USA (Bortle Class 4).

Arp 99/Hickson 93 Galaxy Group in Pegasus

This is a grouping of galaxies collectively known as Arp 99 (Arp Catalog of Peculiar Galaxies) and as Hickson 93 (Hickson Compact Group 93), all found in the constellation Pegasus. The three main galaxies in the image are the elliptical galaxy (center) NGC 7550, NGC 7547 is the small spiral galaxy to the left, and NGC 7549, the stretched barred spiral below NGC 7550 (this is interacting with the elliptical galaxy).
Tech Specs: Meade 12” LX-90, Antares Focal Reducer, ZWO AS071 running at -10C, Celestron CGEM-DX mount, ZWO ASIAir Plus, ZWO EAF, 108 x 60 second exposures, darks from the library and flats after the imaging session. Image Date: October 29, 2022. Location: The Dark Side Observatory (W59), Weatherly, PA, USA (Bortle Class 4).

Arp 229 Elliptical Galaxy in Pisces

The focus of this image is the pair of elliptical galaxies in the center of view, they are the large elliptical galaxy NGC 507 and the smaller one above is NGC 508. They are located 210 million light years away in the constellation of Pisces. NGC 507 is classified in the Arp Catalog as Arp 229, Galaxies with Concentric Rings. Looking closely at my image you can see the “ring” which Arp identified. There are so many galaxies in this image!
Tech Specs: Meade 12” LX-90, Antares Focal Reducer, ZWO AS071 running at -10C, Celestron CGEM-DX mount, ZWO ASIAir Plus, ZWO EAF, 108 x 60 second exposures, darks from the library and flats after the imaging session. Image Date: October 29, 2022. Location: The Dark Side Observatory (W59), Weatherly, PA, USA (Bortle Class 4).
ANNOTATED IMAGE

Interacting Galaxies Arp 307 (NGC2872 and NGC2874)

This is the galactic group Arp 307, consisting of interacting galaxies NGC 2872 and NGC 2874 in the constellation Leo.
The Atlas of Peculiar Galaxies is a catalog of peculiar galaxies produced by Halton Arp in 1966. A total of 338 galaxies are presented in the atlas, which was originally published in 1966 by the California Institute of Technology. The primary goal of the catalog was to present photographs of examples of the different kinds of peculiar structures found among galaxies.
Tech Specs: Orion 8" f/8 Ritchey-Chretien Astrograph Telescope, Sky-Watcher EQ6R-Pro mount that is pier mounted, ASI071MC-Pro, ZWO AAPlus, ZWO EAF, 54 x 60 seconds at -10C, processed using DSS and PixInsight. Image Date: March 26, 2023. Location: The Dark Side Observatory (W95), Weatherly, PA, USA (Bortle Class 4).

Face On Spiral Galaxy NGC2857 (Arp1)

This is the face on spiral galaxy NGC2857 and is also the first entry in the Arp catalog. It's Arp class is "spiral galaxies with low surface brightness". NGC2857 shows two very long thin spiral arms, as can be seen in my image. The galaxies of the lower left are NGC2856 and NGC2854, they are interacting galaxies and also listed in the Arp catalog as Arp285. These will be imaged at a later date using the Meade 12” to gain additional data.
Observation data (J2000 epoch)Constellation: Ursa MajorRight ascension: 09h 24m 37.698sDeclination: +49° 21′ 25.69″ Distance: 225.21 ± 0.00 klyApparent magnitude (V): 12.27
Tech Specs: Orion 8" f/8 Ritchey-Chretien Astrograph Telescope, Celestron CGEM-DX pier mounted, ZWO ASI290MC and ASI071MC-Pro, ZWO AAPlus, ZWO EAF, 82 x 60 seconds at -10C plus darks and flats, processed using PixInsight and DSS. Image Date: January 26, 2022. Location: The Dark Side Observatory, Weatherly, PA, USA (Bortle Class 4).
ANNOTADE IMAGE

Merging Galaxies in Draco - Arp 81

Arp 81 is a strongly interacting pair of galaxies, seen about 100 million years after their closest approach. It consists of NGC 6621 and NGC 6622. NGC 6621 is the larger of the two, and is a very disturbed spiral galaxy. The encounter has pulled a long tail out of NGC 6621 that has now wrapped behind its body. The collision has also triggered extensive star formation between the two galaxies. Scientists believe that Arp 81 has a richer collection of young massive star clusters than the notable Antennae galaxies (which are much closer than Arp 81). The pair is located in the constellation of Draco, approximately 300 million light-years away from Earth. Arp 81 is the 81st galaxy in Arp's Atlas of Peculiar Galaxies.(Credit/Source: https://esahubble.org/images/heic0810bd/)
Observation data (J2000 epoch)Constellation: DracoRight ascension: 18h 12m 55sDeclination: +68° 21′ 48″Apparent magnitude (B): 13.6
Tech Specs: Meade 12” LX-90, Celestron CGEM-DX pier mounted, Antares Focal Reducer, ZWO ASI290MC (on Orion 60mm Guidescope), ASI071MC-Pro, ZWO AAPlus, ZWO EAF, 96 x 60 seconds at 0C plus darks and flats, processed using PixInsight and DSS. Image Date: June 5, 2022. Location: The Dark Side Observatory, Weatherly, PA, USA (Bortle Class 4).

Interacting Galaxies NGC 5930 and 5929 - Arp 90

Here is a view of interacting galaxies NGC 5930 and NGC 5929 found in the constellation Bootes. Arp listed this galactic pair in his catalog of peculiar galaxies as Arp90. The small fuzzy galaxy in the upper left is called UGC 9857 and is listed as magnitude 15.8.
Observation data (J2000 epoch)Constellation: BoötesRight ascension: 15h 26m 07.987sDeclination: +41° 40′ 33.92″Distance: 133 MlyApparent magnitude (V): 12.2
Tech Specs: Meade 12” LX-90, Celestron CGEM-DX pier mounted, Antares Focal Reducer, ZWO ASI290MC (on Orion 60mm Guidescope), ASI071MC-Pro, ZWO AAPlus, ZWO EAF, 69 x 60 seconds at 0C plus darks and flats, processed using PixInsight and DSS. Image Date: June 4, 2022. Location: The Dark Side Observatory, Weatherly, PA, USA (Bortle Class 4).

Galaxy IC356 (Arp213) in Camelopardalis

IC 365, also known as Arp 213, is a spiral galaxy located in the constellation Camelopardalis (the Camel). The galaxy appears red in color, because it is situated behind the dust of the Milky Way, at a distance of approximately 50 million lightyears. If you look close you can make out some of the dark dust lanes in the spiral arms. Arp included this galaxy in his list of peculiar galaxies because of the odd dark lane that goes from the central region of the galaxy and extends to the 10 o’clock position in my image.
Tech Specs: Orion 8" f/8 Ritchey-Chretien Astrograph Telescope, Celestron CGEM-DX pier mounted, ZWO ASI290MC and ASI071MC-Pro, ZWO AAPlus, ZWO EAF, 108 x 60 seconds at -10C plus darks, processed using DSS. Image Date: November 8, 2021. Location: The Dark Side Observatory, Weatherly, PA, USA (Bortle Class 4).

Galaxy NGC 1961 (Arp 184)

NGC 1961 is an unusual galaxy, located about 171 million light-year from Earth, toward the constellation Camelopardalis. Because of its unusual appearance, Arp listed in his Catalog of Peculiar Galaxies as entry number 184.
Tech Specs: Orion 8" f/8 Ritchey-Chretien Astrograph Telescope, Celestron CGEM-DX pier mounted, ZWO ASI290MC and ASI071MC-Pro, ZWO AAPlus, ZWO EAF, 108 x 60 seconds at -10C plus darks and flats, processed using PixInsight and DSS. Image Date: November 8, 2021. Location: The Dark Side Observatory, Weatherly, PA, USA (Bortle Class 4).

NGC 772 (Arp 78) The Nautilus Galaxy

When I first imaged The Nautilus Galaxy (NGC 772/ARP 78) I was fascinated by its shape, one spiral arm stretched outward from the center. This is probably an effect of being tugged on by a satellite galaxy designated as NGC 770 (the bright fuzzy ball of light at the eight o'clock position). NGC 772 is also listed as ARP 78 in the Arp Atlas of Peculiar Galaxies. This catalog was compiled by Dr. Halton C. Arp and it details 338 peculiar galaxies. It is estimated that NGC 772 is twice the size of our Milky Way Galaxy! If you are looking at this image on Facebook or on our web site, I’ve also included an annotated version of the image.
Distance: 130 million light year.Right ascension: 01h 59m 20sDeclination: +19° 00’ 27”Apparent Magnitude: 10.3Apparent Size: 4.57 x 2.52 (arc minutes)
I’ve imaged this galaxy three times in the last seven years, each time bringing out new details from changes in camera sensor technology, software processing and experience.
I’m not sure who first coined the name “Nautilus Galaxy”, but I did find a reference from 2008 by Ruben Kier who states, “I find the shape of NGC 772 resembles the nautilus shell, as illustrated to the right, so I have called it the Nautilus Galaxy.” (REF: http://www.stardoctor.org/772.html) If you Google “Nautilus Shell” you’ll see what he is talking about.
Tech Specs: Orion 8" f/8 Ritchey-Chretien Astrograph Telescope, Celestron CGEM-DX pier mounted, ZWO ASI290MC and ASI071MC-Pro, ZWO AAPlus, ZWO EAF, 178 x 60 seconds at -10C plus darks and flats, processed using PixInsight and DSS. Image Date: November 9, 2021. Location: The Dark Side Observatory, Weatherly, PA, USA (Bortle Class 4).

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