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Arp 118, 


            Gary Imm

Arp 118

Getting plate-solving status, please wait...
Arp 118, 


            Gary Imm

Arp 118

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. 16, 2021Jan. 17, 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: 3.84 days

Avg. Moon phase: 15.92%

Basic astrometry details job: 4267043

Resolution: 2968x1979

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

Data source: Backyard


This Astrobin Debut Object is a pair of interacting galaxies located 400 million light years away in the constellation of Cetus at a declination of 0 degrees. The magnitude 13.2 yellow elliptical galaxy on the right is NGC 1143, while the magnitude 12.9 disturbed spiral galaxy on the left is NGC 1144. Each galaxy is similar in size, spanning 0.7 arc-minutes in our apparent view with a diameter of 80,000 light years.

This galaxy was classified by Dr. Arp into the category of Elliptical Galaxies that are Close to and Perturbing Spirals.

This is one of my favorite Arp objects, particularly the wonderful double ring of blue star clusters around the core of the left galaxy. One ring is horizontal and the other ring is inclined at about the same angle as the galaxy disk. This blue lumpy star cluster pattern is very similar to what is seen in Arp 244, The Antennae Galaxies. It seems likely that interaction of the spiral with the elliptical kicked off the star initiation seen in these blue clusters.

The distant spiral galaxy up and to the right is 2MASX J02550661-0009448, about 0.5 billion light years away with a diameter of 65,000 light years. It has a slightly warped disk.