Sky & Telescope - August 2021 - 59

Face the Challenge
Moving southwest from the 7619/7617
pair, we encounter two spiral galaxies.
D'Arrest discovered NGC 7611 in
September 1862 while observing with
the 11-inch refractor at Copenhagen
Observatory. Located 12.7′ southwest of
NGC 7619, it appears as a moderately
large, smoothly illuminated oval with a
bright stellar core. French astronomer
Stéphane Javelle discovered its similarsize
neighbor, IC 5309, on October 23,
1903. Look for the 13.7-magnitude
spiral 6.8′ northwest of NGC 7611.
IC 5309, involved with a 14th-magnitude
star at its southern tip, is faint and
requires averted vision to detect. You
can also use a pair of stars of magnitude
9.2 (HD 219866) and 9.6 to locate
the galaxy 7.2′ to their south.
The brightest star in the vicinity of
the Pegasus I cluster is 6.9-magnitude
HD 219949, sitting 5.6′ southeast of
NGC 7611. It's a convenient guidepost
for locating the next two objects.
Faraway Galaxies
Object
Type
NGC 7619
NGC 7626
NGC 7623
NGC 7621
NGC 7617
NGC 7631
NGC 7612
PGC 71091
NGC 7615
NGC 7608
UGC 12510
NGC 7611
IC 5309
MCG 1-59-54
MCG 1-59-53
UGC 12535
Elliptical
Elliptical
Spiral
-
Spiral
Spiral
Lenticular
Barred Spiral
Spiral
Spiral
Elliptical
Barred Spiral
Spiral
Spiral
Spiral
Spiral
MCG 1-59-58 Barred Spiral
MCG 1-59-61 -
MCG 1-59-54 lies 7.2′ east-northeast
of HD 219949 and 2.2′ southwest of a
10.2-magnitude star. (It's also about
12′ due south of NGC 7619.) I required
averted vision to see this very faint
dwarf spiral. Its neighbor 4.5′ to the
south-southwest is MCG 1-59-53, a very
elongated, low surface brightness streak.
For an even greater challenge, look
5.2′ southeast of NGC 7626 to see if
you can detect the elongated spiral
UGC 12535. At 185 million light-years,
this is the second farthest galaxy on our
tour. On my most recent visit to the
Pegasus I group, I fi nally spotted this
nearly edge-on spiral with my 30-inch
Dob. The DSS image on page 58 shows a
close companion - even though I didn't
reliably spot it, I have confi dence in my
detection of UGC 12535.
About 4.7′ south of UGC 12535 is
MCG 1-59-58, which may be a barred
spiral or a double system - images show
what might be two nuclei in its core.
Using averted vision with my 18-inch
Dob, I see MCG 1-59-58 as a faint
smudge elongated roughly east-west.
Wrapping Up
For our fi nal stop, let's jump back to
the northern edge of the cluster and
look in on MCG 1-59-61, which you'll
fi nd 16.2′ northeast of NGC 7623. This
nearly face-on barred spiral is probably
the faintest galaxy I have detected so
far in the Pegasus I group and the one I
would describe as the most challenging.
I haven't found a distance estimate or a
visual magnitude for this galaxy, and I
was a little surprised to be able to detect
it. It appears as a small, round splotch
of nebulosity.
Professional astronomers study galaxy
Surface
Brightness Mag(v) Size/Sep
12.9
13
12.8
12.4
13.2
13.2
12.9
14.3
13.3
13.5
14.6
12.3
13.4
15.4
13.8
14.1
13.8
11.1 2.5′ × 2.3′
11.1 2.6′ × 2.3′
12.9 1.2′ × 0.9′
14.7 0.7′ × 0.2′
13.8 0.9′ × 0.7′
13.1 1.8′ × 0.7′
12.8 1.6′ × 0.8′
14.8 0.7′ × 0.5′
14.3 0.9′ × 0.5′
14.2 1.5′ × 0.4′
15.1 1.1′ × 0.6′
12.5 1.5′ × 0.6′
13.7 1.4′ × 0.6′
14.8 1.5′ × 1.4′
14.5 1.4′ × 0.3′
13.3 1.0′ × 0.2′
14.6 1.1′ × 0.5′
Dist
(M l-y)
163
146
162
167
183
163
137
139
197
151
153
139
184
117
116
185
169
RA
23h 20.2m +08° 12′
23h 20.7m
+08° 13′
23h 20.5m +08° 24′
23h 20.4m +08° 22′
23h 20.2m +08° 10′
23h 21.4m
23h 19.7m
23h 19.9m
23h 19.9m
23h 19.3m
23h 19.7m
23h 19.6m
23h 19.2m
+08° 13′
+08° 35′
+08° 34′
+08° 24′
+08° 21′
+08° 16′
+08° 04′
+08° 07′
groups and clusters for a number of reasons.
Galaxy clusters are slow to evolve
and therefore leave indelible evidence of
how they formed. Unlike single galaxies,
clusters are closed systems that tend
to retain their gas and thus provide a
ready laboratory for the study of nucleosynthesis.
They're
also of paramount
importance to our
understanding of
dark matter. Amateur
astronomers
are also drawn to
these clusters. For
me, it's to enjoy the
thrill of the hunt in
tracking down these
faint wisps of light
that push the limits
of detection, to
revel in the contemplation
of our vast
universe, and to
vicariously retrace
the steps of the
great visual observers
of a bygone era.
Dec.
23h 20.3m +08° 00′
23h 20.2m +07° 56′
23h 21.0m
+08° 11′
- - 0.5′ × 0.4′ -23h 21.4m
23h 20.3m +08° 00′
+08° 32′
Angular sizes are from recent catalogs. Visually, an object's size is often smaller than the cataloged value and varies according to the
aperture and magnifi cation of the viewing instrument. Right ascension and declination are for equinox 2000.0.
 Contributing
Editor TED FORTE
enjoys observing
the deep sky
from his backyard
observatory in
southeastern
Arizona.
sk yandtelescope.org * AUGUST 2021 59
http://www.skyandtelescope.org
Sky & Telescope - August 2021

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