British Astronomical Association
Supporting amateur astronomers since 1890

Secondary menu

Main menu

BAA Community Member Pages Alan Snook
Image search

Arp 227

Image

Expand image

About this observation
Observer
Alan Snook
Time of observation
04/12/2016 - 20:40
Object
Arp 227 (NGC 474)
Observing location
Kent
Equipment
0.5m f4.1 Dobsonian
8mm Ethos eyepiece x260
Lumicon deep sky filter
Tags
Like This Image
Share

Arp 227 (NGC 474) is just E of another galaxy, NGC 470 (12.5m 2.8 x 1.7), which is not part of the Arp object. Arp listed this galaxy as an example of concentric rings. The rings belong to NGC 474.

NGC 474 is the smaller but more prominent of the pair due to its bright non-stellar core. The round core sits in an oval halo with the major axis aligned N-S. In deep images the overall impression is circular, not oval. I think the oval halo I have seen is due to the (unresolved) brightest arcs in some of the inner concentric rings. 

NGC 470 shows more detail visually. It is the larger of the pair and the surface brightness is less. There is only a tiny, faint core.  Although diffuse, there are hints of structure which suggest a face-on spiral. In particular there is a contrast effect on the E edge, due to either a dark lane or a bright knot. There is either a foreground star or bright knot in the halo on the W side.

Copyright of all images and other observations submitted to the BAA remains with the owner of the work. Reproduction of the work by third-parties is expressly forbidden without the consent of the copyright holder. For more information, please contact the webmaster.