Sky & Telescope - April 2020 - 55

SK E TCH: ERIC G R A FF; T WO G A L A XIES: ESO / IGOR CHEK A LIN

Astronomical Society members call this
"beautiful little starfall" Rinnan's Run
after Dan Rinnan (see page 84), who
chanced upon it during one of their
2009 observing sessions while perusing
the sky with binoculars. Tomm Lorenzin zeroed in on the southern end of
the line, where the stars are fainter but
more densely packed. He dubbed that
section The Scar in his 1997 online
2000+ Catalog. With 11×80 binoculars
in 1980, California's Dana Patchick
saw a wide V made up of The Scar and
a second starry line reaching northeast from its southern end. I've always
called it Dana's V.
Now that you're acquainted with
the area, look for the galaxy NGC 3423
two-thirds of the way from 35 Sextantis
to the reddish orange star 56 Leonis.
It's stored on the attic ﬂoor of a skinny,
Cepheus-like, stick-ﬁgure house of
ﬁve stars. The house is ½° tall with its
sharply peaked roof aimed south-southwest. NGC 3423 is magnitude 11.1 and
as distant as the Spindle Galaxy.
Through my 130-mm refractor at
63×, NGC 3423 is a 2½′ roundish glow
of fairly low surface brightness embracing a small, slightly brighter core. At
117×, a faint star guards the northeastern edge of the galaxy. My 10-inch
reﬂector at 171× reveals a lovely 3¼′
× 1¼′ oval tipped north-northeast. It
appears very patchy, especially around
the outer edges, giving the impression
of weakly deﬁned spiral arms wrapping
clockwise outward. The core is round
and spans 40″.
Our next two galaxies are nearly
the same magnitude as NGC 3423, but
they're much harder to see. Sextans B

11h 00m

α

10h 30m

+10°

Regulus

ο
π

56

75
0°
69

φ
-5°

9h 30m

ρ
LEO

χ
+5°

10h 00m

59

3423

Sextans B

35

3169

58

9
7

3166
Rinnan's
Run

α

β

3044

θ

2967

ι

HYDRA

δ
Sextans A

SEXTANS

2974
23

ε
-10°

(UGC 5373) is magnitude 11.3, and
Sextans A (MCG-1-26-30) is 11.5. At 5
million light-years, these dwarf galaxies
dwell just beyond the boundaries of our
Local Group.
Sextans B sits 1½° east-northeast of
the pretty, wide, orange-and-gold double
9 Sextantis. In my 10-inch scope at
171×, Sextans B is a very faint glow that
covers about 3′ × 2′ and leans west-

3115

γ

α

24
27

northwest. A 14th-magnitude star is
pinned to its northern edge, and 13thmagnitude stars rest 2½′ north and
east-northeast of the galaxy's center.
Sextans A is located 4.4° south and
a bit east of Alpha Sextantis. With my
10-inch reﬂector at 187×, I could only
pick out its brightest patch, which
lies in the western side of a faint star
pattern that's a lopsided version of

u NGC 3169 (left) and 3166 are distorted by
each other's gravitational pulls. The author also
spotted little NGC 3165 (far right) but didn't
include it in the article because it's
below the 12.0-magnitude cutoff.
u At 60×, the galaxies NGC
3166 and 3169 are easily
located north of a prominent
asterism. Fainter NGC 3156
lies just west of the asterism's
brightest stars. All sketches
represent views through a
6-inch reflecting telescope.
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Sky & Telescope - April 2020

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