The wonderful canopy of stars that fill the sky over or heads, seen best on from a dark, rural location, are all part of the vast Milky Way Galaxy. In the distant background are trillions of other galaxies punctuating the fabric of the Universe. Dozens of these galaxies are close enough and sufficiently bright to be picked up with a common pair of 7x50 binoculars.
The most obvious example is the Andromeda Galaxy, the only one easily visible to unaided eyes. Andromeda is well placed on autumn evenings, but during the springtime is lost in the Sun’s glare.
The evening spring sky contains a wealth of galaxies visible in a small telescope. There are hundreds within reach, scattered across the constellations Virgo, Leo and Coma Berenices. Many of these are among the massive "Virgo Supercluster" some 60 million light years away.
Like people, dogs, geese, trout and wildflowers, galaxies roam in bunches. Attracted by their mutual gravity and having a common origin, galaxies are found in grand clusters, among the largest structures of the cosmos.
Our own Milky Way Galaxy is part of a cluster of galaxies known as the "Local Group." The Milky Way and the spiral galaxy M31,commonly called the Andromeda Galaxy, lead the pack. (M31 is larger.)
Two other neighboring galaxies, M81 and M82, may be seen in binoculars on a dark, clear spring evening. They are not far from the "bowl stars" of the Big Dipper, high up in the northern sky in mid-evening.
Note: Galaxies, at their best, will appear as a very small, dim, gray "fuzzy patch" in binoculars. They do not appear bold, bright, colorful and with detail as you see in most photographs. To me, the very faintness and obscurity adds to the wonder, as it helps me appreciate how incredibly far they are and how amazing it is to glimpse them at all.
M81 and M82 appear very near each other in the sky.
At this time, the Big Dipper is at its highest, with the "handle" to the right and the "bowl" apparently upside down. Use two of the four stars of the "bowl," Phecda and Duhbe, to point to the location of M81/M82. These stars are at opposite corners in the "bowl." Extend an imaginary line the same distance to the lower left (northwest). M81/M82 are within a couple degrees of that point, and if you patiently and slowly scan with binoculars, you should able to find them, especially M81. M81, the brighter of the two, appears just above M82.
In a small telescope (with a main lens or mirror 3 inches wide or larger), using about 60x, you can see how M81appears as a wide oval, brightest in the middle. M82 appears more edge-on, shaped like a clumpy cigar.
M81/M82 were discovered by Johann Elert Bode on December 31, 1774.
They are within the constellation Ursa Major the Big Bear, of which the Big Dipper is a part.
The galaxy pair is 11.8 million light years from the Earth, fairly close in astronomical terms. Photos show that M82 is a grand spiral. M81 is known as a starburst galaxy, with new stars forming at exceptionally high rates. They are only around 150,000 light years apart. The two galaxies interact, and a bridge of hydrogen gas has been detected between them.
Last quarter Moon is this Friday, April 27. This week, do your galaxy-hunting early, before the Moon rises.
Keep looking up!