Hemisphere:  Southern  ·  Constellation: Eridanus (Eri)
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Arp 219, 


            Gary Imm
Arp 219, 


            Gary Imm

Arp 219

Getting plate-solving status, please wait...
Arp 219, 


            Gary Imm
Arp 219, 


            Gary Imm

Arp 219

Imaging telescopes or lenses: Celestron EdgeHD 11

Imaging cameras: ZWO ASI 294 MM Pro

Mounts: Astro-Physics Mach1GTO

Guiding cameras: ZWO ASI 174 MM Mini

Software: Main Sequence Software Sequence Generator Pro  ·  Pixinsight  ·  Stark Labs PHD2 2.6.3

Filters: Astrodon Green 31mm Gen2 I-Series  ·  Astrodon Blue 31mm Gen2 I-Series  ·  Astrodon Lum 31mm Gen2 I-Series  ·  Astrodon Red 31mm Gen2 I-Series

Accessory: ZWO EFW 2″X7  ·  Celestron OAG  ·  MoonLite Focuser for EdgeHD 11

Dates:Jan. 2, 2021Jan. 3, 2021

Astrodon Blue 31mm Gen2 I-Series: 30x120" (gain: 120.00) -20C bin 2x2
Astrodon Green 31mm Gen2 I-Series: 30x120" (gain: 120.00) -20C bin 2x2
Astrodon Lum 31mm Gen2 I-Series: 60x120" (gain: 120.00) -20C bin 1x1
Astrodon Red 31mm Gen2 I-Series: 30x120" (gain: 120.00) -20C bin 1x1

Integration: 5.0 hours

Avg. Moon age: 18.58 days

Avg. Moon phase: 84.19%

Astrometry.net job: 4243723

RA center: 3h 39' 52"

DEC center: -2° 6' 50"

Pixel scale: 0.343 arcsec/pixel

Orientation: -2.038 degrees

Field radius: 0.190 degrees

Resolution: 3374x2127

Locations: Backyard (Mag 20.8 - Bortle 4.5), Onalaska, Texas, United States

Data source: Backyard


This Astrobin Debut Object, also known as UGC 2812, is a collisional ring galaxy located 0.5 billion light years away in the constellation of Eridanus at a declination of -2 degrees. This galaxy was classified by Dr. Arp into the wonderfully named category of Galaxies – Adjacent Loops. I really enjoy looking at collisional ring galaxies – my collection of them is here.

Arp 219 is at the center of the image. The main galaxy is magnitude 14.9 UGC 2812 and the tiny galaxy slightly below and left is magnitude 18.4 2MASX J03395491-0207241. UGC 2812 spans 50 arc-seconds in our apparent view and has a diameter of 120,000 light years.

I am fascinated by so many aspects of this object:

- The star stream arcing above and to the left of the main galaxy
- The contrasting yellow core and blue star formation areas
- The beautiful and well-formed loop below the galaxy

So what is causing the star stream and the beautiful loop? I don’t think it is the tiny galaxy “companion”. There is no distance information for this tiny galaxy. To be at the same distance, this galaxy would be only 30,000 light years in diameter. It looks too well formed to be that small. Plus, I don't see any distinct star streams connecting the two galaxies. So I think the tiny galaxy is far in the distance, a billion miles or more away.

The face-on grand spiral galaxy above and left is UGC 2814, located 430 million light years away. This object is also too far away from the Arp object to be causing the disturbance.

The disturbance galaxy could have been a “hit and run” culprit who has since left the frame. But I believe that the disturbance galaxy was a small companion who is now in the process of being absorbed by the main galaxy. One of the bright blue regions in the main galaxy could be the former core of this companion.

Before leaving this image, don’t miss the fantastic small face-on grand spiral galaxy (2MASX J03392591-0201341) at the top right edge of the image.