Posted by:
Kelly Rae on
May 7, 2010 at
7:26AM PST
Spring Galaxy M101, the Pinwheel Galaxy. Credit: NOAO/AURA/NSF
Spring is the most popular time of year to do some galaxy hunting. During the spring months, the arch of the Milky Way runs closely along the horizon, which means when you are looking up on spring nights, you are peering out into the universe. A number of galaxies are clustered in the spring constellations, from Virgo to Leo north into Ursa Major.
Ursa Major, the constellation of the Great Bear, is easy to spot because of its well-known asterism of the Big Dipper. The Big Dipper is actually the body of the bear and its handle is supposedly the bear’s tail. If you follow the stars off the front of the bowl of the Big Dipper you will spot the stars that mark its triangular head. Two of the brighter galaxies that share very close quarters are located above the bear’s back and about halfway between the last bowl star and the star that marks the bear’s nose.
These two galaxies are M81 and M82. M81, also called Bode’s Galaxy, is the brighter of the two at magnitude 6.9, which makes it visible in binoculars. M81 lies 11 million light-years away. It is a spiral galaxy seen nearly face on. Through binoculars or a telescope, look for its brighter core and the faint glow of its arms. M82, also called the Cigar Galaxy, is dimmer at magnitude 8.4 because it appears edge on. At 12 million light-years distant, it is a physical pair with M81, which may be distorting M82 and causing heavy star formation. The two galaxies can be seen in the same field of view.
M101, at magnitude 7.8, is a beautiful spiral galaxy known as the Pinwheel. It is also found in Ursa Major, but this galaxy lies above the tail of the bear. M101 forms a triangle with the last two stars in the tail, about five and a half degrees from both Alkaid and Mizar. When you are looking at M101, you’re looking twice as far back in time as when you spotted M81 or M82, because the Pinwheel Galaxy lies 24 million light-years away. Look for a bright central core and arms that wrap clockwise around it.
Get more observing tips on other spring galaxies.
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Kelly Kizer Whitt loves clean, clear, and dark skies. Kelly studied English and Astronomy at the University of Wisconsin-Madison and worked for Astronomy magazine. She is currently the Feature Writer for Astronomy and Space at Suite101.com. You can follow her on Twitter at twitter.com/Astronomommy
