Observing the Antlia Galaxy Cluster

High up in the sky these autumn evenings, you’ll find the small faint constellation of Antlia, the air pump. Never heard of it? It's between Vela and Hydra. It was created by Lacaille in the 18th century. 

Probably best known for the iconic image of NGC 2997, the beautiful face-on spiral photographed by David Malin at the AAO.

However our target this month is the Antlia Galaxy Cluster. This is the third closest to our Local Group, with only the Fornax Cluster and Virgo Cluster lying closer. The Antlia Cluster contains about 234 galaxies and is dominated by two massive elliptical galaxies, NGC 3258 and NGC 3268.

The Northern subgroup of galaxies inside the cluster gravitate around NGC 3268, while the Southern subgroup is centered around NGC 3258. Each of the two giant ellipticals contain several thousand globular clusters.

Most galaxies in the Antlia Cluster are early type galaxies, and dwarf elliptical galaxies are the most common galaxy type. The Antlia Cluster is located between 32.58 and 32.71 million light years from Earth.

We will concentrate our observing on the Northern subgroup centered on NGC 3268, an 11.8 mag elliptical galaxy. At 2.5 x 3.0 minutes of arc it's reasonably large, and relatively easy to see in a 10” telescope. The other bright galaxy, NGC 3271 lies 15 minutes ESE of NGC 3268. The 11.8 mag barred spiral galaxy is of similar size to NGC 3268. 

Located 6 minutes North of NGC 3268, is the barred spiral NGC 3269. At 12.3 mag it is still well within reach of smaller scopes. You observe these objects under dark skies. Going out in a suburban sky is not going to auger well for you. 

Just 2.5 minutes west of NGC 3268 is the 12.5 mag NGC 3267. At 1.0 x 1.7 minutes in size, this spiral is the smallest of the quartet.

A number of fainter PGC galaxies also complete the view in larger scopes. Perhaps this cluster is a good target for our astro imagers?