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M81 Galaxy by Starlight
Ssc2019 15d

Credit: NASA/JPL-Caltech

Observation • August 27th, 2019 • ssc2019-15d


The nearby spiral galaxy, Messier 81 (M81) is shown in this image from NASA's Spitzer Space Telescope. Located in the northern constellation of Ursa Major (which also includes the Big Dipper), this galaxy is easily visible through binoculars or a small telescope. M81 is located at a distance of 12 million light-years.

This image shows us M81 at infrared wavelengths of light at 3.6 & 4.5 microns (blue & green). At these shorter wavelengths of infrared light we are seeing the light from the stars in this galaxy, unobscured by dust that blocks our view in the visible spectrum.

M81 appears remarkably smooth in this picture, demonstrating how well-blended the populations of stars can be even in spiral galaxies. The spiral arms so visible in other parts of the spectrum are subdued and gives us a clearer picture of how stellar mass is distributed through the galaxy.

About the Object

M81Messier 81NGC 3031Bode's GalaxyUGC 5318
Galaxy > Type > Spiral
8,500,000 Light Years

Color Mapping

Band Wavelength Telescope
Infrared 3.6 µm Spitzer IRAC
Infrared 4.5 µm Spitzer IRAC


Position (J2000)
RA =9h 55m 33.0s
Dec = 69° 3' 52.7"
Field of View
24.0 x 24.0 arcminutes
North is 30.0° right of vertical