60 ASTRONOMY • APRIL 2018
Choosing the Whirlpool Galaxy, M51,
was easy. It’s my favorite galaxy. Not only
is it bright enough to be visible through
binoculars from suburban skies, but it
shows more subtle detail than any other
galaxy visible from mid-northern latitudes.
You’ll find it within a small trapezoid
of 6th- and 7th-magnitude stars a few
degrees southwest of Alkaid [Eta (η)
Ursae Majoris].
A quick glance through a 3- or 4-inch
telescope will immediately show the
Whirlpool Galaxy’s slightly oval disk and
bright central nucleus. Its smaller compan-
ion galaxy, NGC 5195, is also apparent, as
is an arm that seems to reach out from
M51 to NGC 5195. Studies show, however,
that they are only slightly physically
connected.
Given dark, clear skies, 6- to 8-inch
instruments will reveal the galaxy’s whirl-
pool-like arms wrapping around the central
core. Although they are rather subtle, and
may require a concentrated effort using
averted vision, the spiral arms help rank
M51 as one of the sky’s true
showpieces. If your telescope
isn’t quite large enough to show
them, try to get a view of the
galaxy through a larger instru-
ment, such as at a star party
hosted by a local astronomy
club. It will be worth the trip.
There is no finer close-set
pair of galaxies north of the
celestial equator than M81 and M82. Both
lie at the end of a long line extending to the
northwest from Phecda [Gamma (γ) Ursae
Majoris] through Dubhe [Alpha (α) Ursae
Majoris], in the bowl of the Big Dipper. The
galaxies and Phecda are both about equal
distances from Dubhe, but set directly
opposite one another.
Spiral galaxy M81 shines at 7th magni-
tude, making it bright enough to be seen
through even the smallest pocket binocu-
lar. Through my 8-inch reflector, it displays
a fuzzy, oval disk surrounding a prominent
core. On exceptional nights, I can also
make out some vague irregularities across
the spiral halo using averted
vision. Trying to see M81’s
spiral arms through even
large backyard telescopes,
however, is daunting.
M82 is just half a degree
to the north. Even though it’s about a full
magnitude fainter than its neighbor, it
shows more structural detail through ama-
teur scopes. First thing you’ll notice, and
again averted vision may be needed, is that
M82 appears sliced in half. A dark rift
cleaves the center of the galaxy in two.
That’s the only visual indication we get of
the great turmoil going on inside this dis-
tant galactic island. Studies show that M82
passed near M81 recently (in galactic
terms, that is), with its gravity stirring the
pot. As a result, M82’s structure was dra-
matically disrupted. Although many
sources still refer to this as an irregular
galaxy, a report published in The
Astrophysical Journal in 2005 showed that
M82 is actually a spiral galaxy, but with its
arms greatly disfigured.
Before moving on, can you see two
other galaxies hidden in the same field?
NGC 2976 is southwest of M81. Its low
surface brightness proves challenging
through 6-inch and smaller telescopes.
NGC 3077, to the east-southeast of M81,
is easier to see.
M101 holds a wealth of detail for
patient visitors. You can find it 5.5° east-
southeast of Mizar [Zeta (ζ)
Ursae Majoris] and 5.5° north-
northeast of Alkaid [Eta (η)
Ursae Majoris]. Maybe. I say
“maybe” because locating M101
is easy, but seeing it can be
another matter. Although it is
listed as 8th magnitude, that
A
s winter fades into spring, our nighttime view of the
universe slowly turns away from the plane of the
Milky Way and out toward intergalactic space.
There, we find thousands of other galaxies scattered
across the sky, each an island of billions of stars.
Trying to draw up a short list of the finest
galaxies in the spring sky is daunting. There are
many worthy candidates. Nonetheless, here are
some of my personal favorites.
Sometimes called
the Pinwheel Galaxy,
M101 in Ursa Major
offers a nearly face-on
spiral for observers
with moderate-sized
telescopes. ADAM BLOCK/
MOUNT LEMMON SKYCENTER/
UNIVERSITY OF ARIZONA
Ursa Major’s M81
(left) and M82 bring
together two bright
galaxies in one low-
power telescopic field
of view. GERALD RHEMANN
