stars through their spectra. The Yerkes scheme uses the spectra of stars in the galaxy; the shape, real and apparent; and the degree of the central concentration to classify galaxies. Thus, for example, the Andromeda Galaxy is classified as kS5. See also References External links Galaxies and the Universe – an introduction to galaxy classification Near-Infrared Galaxy Morphology Atlas, T.H. Jarrett The Spitzer Infrared Nearby Galaxies Survey (SINGS) Hubble Tuning-Fork, SINGS Spitzer Space Telescope Legacy Science Project Go to GalaxyZoo.org to try your hand at classifying galaxies as part of an Oxford University open community project Astronomical classification systems Extragalactic astronomy Edwin Hubble