GALAXY GAZING: Spring Galaxies: M81, Bode’s Galaxy
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Amateur astronomers always look forward to spring because the nights are warmer; our fingers don’t stick to frozen mounts; and our breath won’t instantly frost up our eyepieces. As a bonus, spring skies are often known as the Galaxy Season: the Northern Hemisphere’s ideal time of the year, when most of the larger, brighter and most spectacular galaxies are nicely positioned high in the sky after sunset for the best viewing and imaging.
When observing deep-sky objects – or any object in the sky, for that matter – it’s always best when they’re high above the horizon. Basically, you’re looking through less atmosphere and have less atmospheric distortion, or what we call good or bad “seeing”: when turbulence distorts the view. This is similar to when you look at a fish under water when there are waves over it versus still water (although sometimes photons are easier to catch than a fish!).
One of the finest showpiece galaxies of the spring skies is M81, also called Messier 81 or Bode’s Galaxy. It’s bright enough to be seen with binoculars in relatively dark skies, and it’s partnered with a smaller galaxy named M82 or Cigar Galaxy.
Johan Elert Bode discovered M81 in December 1774, so he’s got his name on it. In 1779, astronomer and comet searcher Charles Messier added it to his catalog of Messier objects, which he created to document objects that were not comets to make his comet-searching quest easier.
In urban areas, it would appear as a small, gray blob when using a modest telescope of six or more inches in diameter. If viewed from a very dark site such as Newport State Park, it would be possible to just make out some of the spiral arms with a 10-inch or larger telescope. It’s a fun object to study for a while through the eyepiece on a warm evening because the longer you study it, the more you can make out some of the finer details.
To find M81, look for the constellation of Ursa Major, the Big Bear. The familiar shape of the Big Dipper is the core of that constellation. The galaxy is just off the end of the dipper’s bowl, as if it’s been “splashed” out of the bowl.
This galaxy appears just under magnitude 7 in the sky. The larger the magnitude number, the dimmer the object. For example, the planet Venus at its brightest can be -4 magnitude (look for it after sunset in the coming weeks).
The distance to M81 is 11 million light years. The light we see from the galaxy now has been traveling across space since, well, before the first humans appeared on Earth around 7 million years ago. Just remember not to blink when that photon of light finally completes its long journey to your eye!
Smear yourself up with some bug spray, grab a blanket and binoculars, and enjoy the spring skies!
Tom Gwilym, vice president of the Door Peninsula Astronomical Society (DPAS) in Sturgeon Bay, is a local astronomer who operates the DPAS’s Leif Everson Observatory and its planetarium show. Witness the fruits of Gwilym’s galaxy gazing at nightskiesnetwork.com, and connect with the DPAS on Facebook at “Door Peninsula Astronomical Society” to read about space-exploration current events and see the latest images from its telescope.