M81 in True-Color
This true-color composite CCD image shows the familiar appearance of M81
(NGC 3031). The central bulge has the yellowish color of an old stellar
population, fading to the blue tints of star-forming regions in the outer
spiral arms. This is a "grand-design" spiral, perhaps due to an encounter
with neighboring M82 outside the field to the north (top). Dust lanes also
marking the spiral pattern are especially visible where they block the
background light of the bulge (which they give a reddish hue, blocking blue
light more effectively than red).
This image was taken with a focal-reducer camera on the 1.3-meter (50-inch)
telescope on McGraw-Hill Observatory on Kitt Peak, Arizona, and was provided
by Greg Bothun (University of Oregon). The field shown is 8.7 by 12.3
arcminutes in size. The relay optics needed to image such a nearby galaxy all
at once produced reflections of the brighter stars, visible as red or blue
patches around the image edge; the black centers of bright star images are due
to digital overflow in the camera electronics.
M81 multiwavelength data |
Messier gallery |
Galaxies |
Image gallery |
UA Astronomy |
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keel@bildad.astr.ua.edu
Last changes: 5/2001 © 2001