Arp 315 / NGC 2830 / NGC 2831 / NGC 2832

Object Type(s)Galaxy, Galaxy Cluster
Relevant Catalog(s)All (Chron), Arp, NGC
Arp CategoryGroups of galaxies
Obs. Lat/Long42° 17', 073° 57'
ConstellationLynx
Date and Time Observed2026-03-02 22:17:00
InstrumentEdgeHD 8" w/f7 reducer-1,422mm FL
CameraPlayer One Apollo-M Mini
Image DetailsTransparency: Fair. Seeing: Fair. Total integration time was 60m. Exposures 20s@225g, No Filter. Dithered and recentered in SharpCap. No guiding.
DescriptionArp's criteria for selecting galaxy clusters are often opaque, and this is a good example. Here his remarks opine: "Companion E[lliptical] is quite compact". Presumably, this means he found the tightness of this grouping peculiar. NGC 2832 is the dominant E galaxy, NGC 2830 is the spiral galaxy to the upper right, and presumably NGC 2831 is the "compact" companion. These three galaxies are at the center of a much larger cluster, designated Abell 779 with at least 30 members. The original Abell cluster list was based on the 1958 Palomar Sky Survey, which didn't get terribly "deep" by modern standards. Today, it's tough to find an "official" count because people count galaxies in their images which invariably show many more galaxies than did Abell's 1958 POSS images. I've seen estimates between 32 and 80. Of course, many of the additional galaxies are background galaxies and not necessarily part of a real "cluster".

Captured on a full moon evening.
Catalog Links
 All Listings 
Featured Image