Types of Galaxies  (pg. 254-255)
• Spirals
–       Sa                   Sb              Sc
   (large nuclei        small nuclei)
   (little gas,dust    lots of gas, dust)
–      SBa                SBb            SBc    (as above, with BARS)
• Ellipticals
– E0  E1 E2 E3 E4 E5 E6 E7
(spherical)               (highly elliptical)
• Irregulars