skyandtelescope.org • JUNE 2020 21
Remarkable Shapes, etc.” The galaxy was
obvious at low power during the star-hop.
NGC 5109 is one of a close pair of
galaxies 1.4° southwest of NGC 5204.
The fainter of the two, indicated with
an arrow in the image on page 16, is
often designated NGC 5113. Gottlieb’s
excellent website (https://is.gd/Gottlieb)
discusses the history behind NGC 5109
and NGC 5113. There’s no visually
detectable galaxy at Herschel’s position
for NGC 5113 (which he observed 11
months prior to NGC 5109). Astrono-
mers studying the region later on
concluded that a faint galaxy nearby
was, in fact, the object that Herschel had
actually observed. Gottlieb’s entry notes
that Harold Corwin (of the NGC/IC
Project) leans toward NGC 5113 being
the same object as NGC 5109. Images do
show an elongated and mottled galaxy
that is much fainter than NGC 5109
at the position at which the Millen-
nium Star Atlas plots NGC 5113. This is
the object that I observed, but I note in
my master observing log that the faint
galaxy should probably be identifi ed as
CGCG 294-034 rather than NGC 5113.
Along with all the NGC galaxies in
this article, NGC 5113 is listed among
William Herschel’s 2,400+ deep-sky
discoveries. It’s very unusual for one of
these galaxies to be diffi cult to see with
my 16-inch. My experience in observ-
ing targets plucked from Herschel’s full
list has been that if there’s a group of
four or fi ve galaxies in a tight clump on
my atlas, all of them detectable with my
16-inch, Herschel usually noted only the
one or two brightest. So I doubt that he
had seen an object as challenging as the
galaxy labeled NGC 5113.
I located the spiral NGC 5109 at 76×
with some effort. At 203× it’s fairly faint,
elongated by 4:1, and has a somewhat
brighter core along the long axis. The
nucleus is barely discernible, and a very
faint star sits at the southern tip of the
galaxy. I could just detect the adjacent
galaxy at magnitude 15.3, some 5′ north-
east of its brighter companion.
UGC 8837, another member of the
M101 Group, hides 1.3° west-southwest
of M101. While at magnitude 13.4, it’s
4.6′ long, which yields a surface bright-ness of just 15.1 magnitudes per square
arcminute. With the 16-inch it was
large, elongated, and extremely faint.
This ghost was very diffi cult, but the
position angle was correct, so I was con-
fi dent I’d bagged it. A barred irregular
galaxy, it’s only 13′ northeast of a bright
magnitude-5.7 star, 86 Ursae Majoris,
which might be why it wasn’t discovered
by the great visual observers of the late
18th and 19th centuries. Then again,
my notes say “not something that you
would ever sweep up” with a 16-inch.
NGC 5368 , in the same fi eld as
UGC 8337, 26′ to its north, was fairly
bright in the 16-inch. It’s small and
round with a nucleus. I saw NGC 5368,
a mixed spiral, immediately at low
power during my star-hop.Concluding Trio
NGC 5238 , a dwarf irregular galaxy 5°
southwest of M101 in Canes Venatici,
is very faint and amorphous and is
possibly a member of the M101 Group.
Adjacent NGC 5225, a much easier gal-
axy since I can spot it with low power, is
in the same high-power fi eld 15′ farther
west-southwest of NGC 5238. A spi-
ral, it’s small and round and showing
a nucleus. Just barely back across the
border in Ursa Major, but also obvious
in the same medium-power fi eld of view
½° southeast of NGC 5225, the len-
ticular NGC 5250 is fairly bright, very
small, and round, with a nucleus.
I hope you enjoyed this visit to M101,
the Pinwheel, and the survey of its com-
panions. Maybe this June — or perhaps
even next June, or one several years later
— you’ll take a peek for yourself.¢ Contributing Editor ALAN WHITMAN
thanks the International Astronomical
Union for minor planet 21330 Alanwhit-
man. This ying mountain will save his
heirs the cost of a gravestone.tMANY FLAVORS The galaxies in this sample
come in many shapes and orientations. These
DSS images are approximately 13′ × 13 ′. The
spirals are the most recognizable, but the
edge-on lenticulars, such as NGC 5422, are
curious to behold. Can you discern the different
characteristics of M101’s companions?POSS-II / STSCI / CALTECH / PALOMAR OBSERVATORY (4)
SAO 29187NGC 5443NGC 5678NGC 5204NGC 5422