My first Magazine Sky & Telescope - 04.2019 | Page 56

APRIL 2019 OBSERVING
Deep-Sky Wonders by Sue French
Small-Scope Galaxies
Turn your optics toward these intriguing “island universes.”
One thinker gazed upon the distant sky
Until he dreamed the Cosmos’ mystic dream.
He watched the “Pageant of the Stars” go by
And caught the faint and fascinating gleam
Of island universes, nebulae.
—Lisa Oland, The Star-Gazer, 1937
evolutionary ideas on the nature
of the heavens were heartily tossed
about early last century. Dutch-Amer-
ican astronomer William J. Luyten
discussed these concepts in his 1928
book The Pageant of the Stars, where he
wrote: “We see the abysmal chasms of
space strewn with countless ‘island uni-
verses,’ vast conglomerations of matter
far beyond the confi nes of the Milky
Way.” Today we call them galaxies.
The origin of the term “island uni-
verses” as used for external galaxies has
R
long intrigued and confused me, for
the matter is far from simple. Tackling
the problem once more for this article,
I was thrilled to fi nd that Tom Siegfried
of Science News had already untangled
the twisted strains of this story. Credit
is most commonly given to philosopher
Immanuel Kant, who in 1755 reasoned
that some “nebulae” were distant
systems akin to our Milky Way, but
he didn’t call them islands. Although
others have been nominated for father
of this phrase, its most likely origin
may surprise you — Ormsby MacKnight
Mitchel, founder of the Cincinnati
Observatory. Mitchel frequently used
the expression “island universe” in his
popular lectures and in his magazine,
The Sidereal Messenger, which pioneered
the term in 1846. The whole, fascinat-
ing story can be read at https://is.gd/
SNIslandUniverse .
Observers often think of galaxies
as prey for large telescopes, but with
patient study you’ll fi nd quite a few that
reveal their charms to small scopes. All
shown here were observed with my 130-
mm refractor from my semirural home,
but the sketches were later contrast-
enhanced to help you pick out features
you might try to see. They appear much
more subtle at the eyepiece.
Our fi rst small-scope galaxies are
Messier 81 and Messier 82, seen as a
pair of dust bunnies just behind the Big
Bear’s ear (24 Ursae Majoris) through
my 9×50 fi nderscope. Some observers
have even been able to spot M81 with
the unaided eye. They’re nice and bright
at 23×, more so M81 with a prominent
core that intensifi es toward the center,
whereas M82’s signature cigar shape
looks patchily luminous. Zooming in
on each galaxy at 164×, M81 hosts a
small nucleus ensconced in a fl eecy
core. South of the core, two foreground
stars are pinned to M81’s face. A pair of
spiral arms can be teased from the haze,
each one winding about halfway around
the galaxy. M82 is gorgeous, displaying
obvious dark lanes and bright patches.
Its ruffl ed façade is likely due to a close
The interacting galaxies that
make up the Leo Triplet lie
within ½° of one another, making
for an attractive view in the eye-
piece. The 7th-magnitude fore-
ground star HD 98388 shines
between M65 and NGC 3628.
54
A PR I L 2 019 • SK Y & TELESCOPE