Sky & Telescope - March 2024 - 20

Ursa Major Targets
M82
M81
IC 2574
NGC 3077
NGC 2976
MAJESTIC DUO The striking pair of M81 and M82 anchor an attractive quintet of galaxies in the northern reaches of Ursa Major. Besides several
Messier targets, the constellation also offers a great variety of more challenging galaxies at which you can point your telescope. You might be able to
fit some in the same field of view (as with M81, M82, and NGC 3077 shown above), while for others you'll need to do a bit of star-hopping. This image
was acquired with a 4-inch telescope.
group, but it's also the brightest in the constellation. The
elegant spiral forms one of the best-known galaxy pairs in
the heavens with its neighbor, M82 (fondly called the Cigar
Galaxy). Separated by just 37′, the duo makes a remarkable
sight in a wide-field eyepiece and is obvious in binoculars.
While M81 is large and bright at magnitude 6.9, I find its
fainter 8.4-magnitude companion to be far more interesting.
A starburst galaxy, M82 is particularly prone to supernovae
- several have been observed since 2004 alone, and radio
observations have revealed a further number of supernova
remnants. You'll easily spot the pair a bit more than 10°
northwest of 2nd-magnitude Alpha (α) Ursae Majoris, familiarly
known as Dubhe.
German astronomer Johann Elert Bode discovered both
objects on December 31, 1774. Pierre Méchain, Charles
Messier's younger colleague, independently discovered the
pair in August 1779. William Herschel observed them on
several occasions, and during one session an error in position
led his astronomer sister, Caroline Herschel, to confuse M81
with M82. This may have influenced John Herschel, William's
son, for he listed M82 as a new object in his catalog that he
published in 1847 based on observations from his observatory
at the Cape of Good Hope. John Louis Emil Dreyer finally
20 MARCH 2024 * SKY & TELESCOPE
righted this confusion when he published the New General
Catalogue of Nebulae and Clusters of Stars in 1888, in which he
assigned each object its current NGC designation.
NGC 3077 fits in the same low-power field of view as
M81. Astronomers sometimes refer to this 10th-magnitude
irregular galaxy as the Garland, a name that perhaps more
properly applies to a string of knots that extends toward the
southeast from the southern edge of the galaxy. These structures
comprise groups of blue stars that were probably drawn
out of NGC 3077 during an interaction with M81 and are
only detectable in large-scale photographs. In the eyepiece,
NGC 3077 appears as a large irregular oval with a conspicuous
core, which itself brightens to a small, obvious nucleus.
There's no sign of the namesake garland of stellar knots even
in my 30-inch Dob.
From M81, scan 1.4° southwest to arrive at another 10thmagnitude
galaxy, NGC 2976. It's an irregular dwarf spiral
that has no central condensation or apparent core. In my
18-inch at 197× it has a very mottled appearance, and I can
see at least three brighter patches presumably marking starforming
regions. A study published in 2010 of the star-formation
history of NGC 2976 using the Hubble Space Telescope
determined that active star formation is shutting down in the
FRANZ KLAUSER / MANFRED WASSHUBER / CCD GUIDE

Sky & Telescope - March 2024

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