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Arp 17, 


            Gary Imm

Arp 17

Getting plate-solving status, please wait...
Arp 17, 


            Gary Imm

Arp 17

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

Dates:Jan. 4, 2021Jan. 5, 2021

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

Integration: 5h

Avg. Moon age: 20.66 days

Avg. Moon phase: 65.51%

Basic astrometry details job: 4236678

Resolution: 2560x1928

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

Data source: Backyard


This Astrobin Debut Object object, also known as UGC 3972, is a distorted spiral galaxy located 240 million light years away in the constellation of Camelopardalis at a declination of +74 degrees. It spans 1 arc-minute in our apparent view, which corresponds to a diameter of 70,000 light years. This galaxy was classified by Dr. Arp into the category of Spiral Galaxies – Detached Segments. I think for Dr. Arp that category was the equivalent of throwing in the towel. I wish he would have been brutally honest and just had a category called Spiral Galaxies - Your Guess is as Good as Mine!

This is a tough one to understand. The two bright areas are classified as 2 different galaxies – PGC 21685 (magnitude 16.0) on the top and PGC 21693 (magnitude (14.6) in the center. These 2 bright areas are connected by bending star streams. But it is hard to visualize what is happening here. I believe that the center bright area is the core of the main object we are seeing. But the bright area above doesn't look like another galaxy core to me - it is much more blue than white, and there is so little signal above, left or right of it. A set of star clusters makes more sense to me, but that still doesn't look quite right.

If you have any ideas on what we might be looking at here, please share them below!