Astrophilia

Elliptical galaxies, like the name suggests have an elliptical shape with no specific axis of rotation. Elliptical galaxies are classified on the basis of their eccentricity, ie how much they deviate from a circle. The class starts from E0 which are the most circular galaxies to E7 which are the most elliptical in shape. Elliptical galaxies are also divided into stages. Compact elliptical galaxies are denoted by cE, normal ellipses just by E and late elliptical galaxies by E+. For example the galaxy M32, located in the constellation Andromeda is denoted cE2. It looks like this. It is clearly seen that it is only slightly elliptical and hence denoted by 2. Another elliptical galaxy is M59 which is more elliptical than M32 and hence designated as E5. It looks like this.

Galaxies are mainly of three types - Spiral, Elliptical and Irregular. They are subdivided into classes and designated a specific type. Spiral Galaxies :  They have three main features namely a bulge , a halo and a disc . The bulge is the central portion of the spiral which is significantly brighter than the rest of the galaxy. The bulge of most galaxies is known to contain a super massive black hole (SMBH) in it. The disc consists of the spiral arms around the bulge. The halo is a faint enclosure around the galaxy. The halo mainly contains globular clusters which contain old stars. Spiral galaxies are categorised into two varieties. The spiral galaxies, whose arms extend right from the bulge are termed as ordinary spiral galaxies and designated as SA. On the other hand, some spiral galaxies have spiral arms which don't extend from the bulge, but extend from an elongation of the bulge. Theses galaxies are known as Barred Spiral Galaxies and are designated as SB.  These