M94 as photographed by the Kitt Peak National Observatory in the visual (red) light, with the 36-inch (0.9 meter) telescope, by W. H. Waller (Hughes STX, UIT Science Team). In this spectral range, M94 shows a very bright central bulge, composed mostly of old, cool stars, the main disk with many short spiral arms, and an extensive, faint outer ring.
UV photo from the Ultraviolet Imaging Telescope (UIT), a 38-cm f/9 Ritchey-Chretien telescope, on the Astro-2 mission, photographed during the nighttime of March 12, 1995 during the Astro-2 mission of the Space Shuttle Endeavour. This is a 1040 seconds exposure made at an effective wavelength of 1520 angstroms (152 nanometers), with a bandwidth of 354 angstroms (35.4 nanometers). This is a false-color image coded for UV intensity.
A remarkable giant ring of hot young stars appears in this ultraviolet image of M94, a striking contrast to the visual light image. The central bulge is almost invisible. The stars in this ring formed in the last 10 million years (before the light we see was emitted); these hot stars are intensely visible in the UV range of the spectrum. Because of the large number of young hot stars, M94 is called a starburst galaxy. This image was taken to study why almost all massive star formation in M94 is concentrated in a very narrow zone and has not occurred in other parts of the galaxy.
Last Modification: June 20, 1999