ARP Galaxies

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



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).