Characteristics of Galaxies
Classification: The Hubble Tuning Fork
Elliptical: E0--E7 Spheroids, E0 is spherical, E7 least spherical.
    Population II stars, little dust, almost no star formation.
Normal Spirals: Sa, Sb, Sc Sa is most tightly wound, Sc least.
    Population I stars in disk, Pop. II in nucleus. Dust and star
    formation in disk.
Barred Spirals: Sba, Sbb, Sbc Have bars across nucleus, Same
   winding rules as normal spirals.  Same content as normal.
Irregulars: No definite shape. Ex. Large and small Magellanic
   clouds.  Dominate universe by number, although generally           
    smaller.  Star formation, but less dust than disks.
Peculiar: (Pec) Have a definite form, but with peculiarities.
    Radio jets or other strangeness.