Hemisphere:  Southern  ·  Constellation: Eridanus (Eri)  ·  Contains:  IC 399  ·  IC399  ·  NGC 1741  ·  NGC1741  ·  PGC16570  ·  PGC16571  ·  PGC3092704
Getting plate-solving status, please wait...
Arp 259 (Hickson 31), 


            Gary Imm
Arp 259 (Hickson 31), 


            Gary Imm

Arp 259 (Hickson 31)

Getting plate-solving status, please wait...
Arp 259 (Hickson 31), 


            Gary Imm
Arp 259 (Hickson 31), 


            Gary Imm

Arp 259 (Hickson 31)

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. 17, 2021Jan. 18, 2021

Astrodon Blue 31mm Gen2 I-Series: 30x120" (1h) (gain: 120.00) -20C bin 2x2
Astrodon Green 31mm Gen2 I-Series: 30x120" (1h) (gain: 139.00) -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: 4.78 days

Avg. Moon phase: 23.79%

Astrometry.net job: 4204088

RA center: 5h 1' 37"

DEC center: -4° 15' 30"

Pixel scale: 0.343 arcsec/pixel

Orientation: -1.629 degrees

Field radius: 0.162 degrees

Resolution: 2819x1907

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

Data source: Backyard


This Astrobin Debut Object consists of six galaxies located 190 million light years away in the constellation of Eridanus at a declination of -4 degrees. It is both an Arp and a Hickson object.

This object spans 1.8 arc-minutes in our apparent view, which corresponds to a width of 100,000 light years. It was classified by Dr. Arp into that wonderfully titled category of Galaxies – Irregular Clumps.

My interpretation when first viewing my processed image was that this is a long irregular galaxy, twisted around and looping back upon itself by interaction with the dwarf galaxy IC 339 (below and left of Arp 259). But that interpretation is entirely incorrect. Studies based on velocity measurements have concluded that this object consists of the dwarf galaxies labeled A thru G in my mouseover image. These galaxies are also known as Hickson 31. These galaxies seem to me to be in the process of merging. Each galaxy has a blue tint, but that tint varies. I especially like the difference in tint between A and C.

Just to complicate things a bit, you may have noticed that galaxy D has an orange tint and not a blue tint like its companions. Color is so useful in these images! Galaxy D is much further away, at 1.25 billion light years, and obviously is not a member of this object.