Celestial hemisphere:  Northern  ·  Constellation: Pisces (Psc)  ·  Contains:  IC 1685  ·  IC 1687  ·  NGC 507  ·  NGC 508
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NGC 507 Galaxy Group in Psc - Arp 229., 


NGC 507 Galaxy Group in Psc - Arp 229.
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NGC 507 Galaxy Group in Psc - Arp 229.


Imaging Telescopes Or Lenses
Orion Optics UK DX 250
Imaging Cameras
Starlight Xpress H9C
Vixen GPDX w/ SS2K
PHD · Astroart 3 · NEAT · PixInsight
Guiding Cameras
KWIQ Guider

Acquisition details

Oct. 13, 2010
50×120(1h 40′)
1h 40′
Avg. Moon age:
6.07 days
Avg. Moon phase:

Basic astrometry details

Astrometry.net job: 282239

RA center: 01h23m33s.6

DEC center: +33°1731

Orientation: -178.757 degrees

Field radius: 0.263 degrees

Resolution: 640x478

File size: 71.1 KB

Locations: Home, Weymouth, Dorset, UK, United Kingdom

Data source: Backyard


Lying between M31 and M33 is this interesting little galaxy group. Arp 229, also known as NGC 507 and NGC 508 is a little group in Psc but right on the border of And.

Dr Arp listed it in his Atlas of Peculiar Galaxies under the heading of 'Concentric Rings'. I must admit it taxes the imagination to see these 'concentric rings' - even the 200" atlas image is inconclusive, although Arp does concede the rings have 'a small density difference'.

It was extremely cold when I collected this data and there was a bright moon not far away but I needed to get this one before it slips away and there haven't been too many observing opportunities in the last couple of months.

I've identified most of the main players in the group and they are pretty faint and small:

NGC 507 is mag. 12.2, s.b. 15.8, GX class E/S0, size 4' x 4'.

NGC 508 is mag. 14.1, s.b. 14.8, GX class E0, size 1.3' x 1.3'.

NGC 504 is mag. 14.0, s.b. 13.3, GX class S0, size 1.6' X 0.4'.

NGC 503 is mag. 15.3, s.b. 12.7, GX class S0, size 0.4' x 0.3'.

NGC 494 is mag. 13.8, s.b. 14.1, GX class Sab, size 2.1' x 0.8'.

IC 1687 is mag. 14.8, s.b. 12.8, GX class E, size 0.5' x 0.3'.

CGCG 502-72 is mag. 15.5, s.b. 12.9, GX class S0, size 0.4' x 0.3'.

There are one or two possible quasars nearby, I have identified 1 at mag 19.9 and indicated it on the image. No redshift data available.

z for the central region of ngc 507 is 0.01646, which corresponds to a distance of 65.5 Mpc, relatively close in the scheme of things.

My image, using the 10" f4.8 reflector is the sum of 50 x 120 second exposures. Guided using the KWIQ guider/PHD combination. Acquisition, colour conversion and initial processing done using AstroArt3; some further processing in Pixinsight to help with the moonglow.



  • NGC 507 Galaxy Group in Psc - Arp 229., 


  • Final
    NGC 507 Galaxy Group in Psc - Arp 229., 


  • NGC 507 Galaxy Group in Psc - Arp 229., 



Sky plot

Sky plot


NGC 507 Galaxy Group in Psc - Arp 229.,