In the 1920s, astronomer Edwin Hubble developed a scheme for classifying galaxies by shape and structure. Elliptical, spiral, and barred spiral galaxies have descriptive names. Galaxies with no apparent structure are classified as irregular, and galaxies that have definite structures but don't fit neatly into the existing categories are called peculiar.

  !   Click each galaxy icon to view a telescopic image of that type of galaxy.

* The Digitized Sky Survey was produced at the Space Telescope Science Institute under U.S. Government grant NAG W-2166. The images of these surveys are based on photographic data obtained using the Oschin Schmidt Telescope on Palomar Mountain and the UK Schmidt Telescope. The plates were processed into the present compressed digital form with the permission of these institutions.