Sky & Telescope - July 2024 - 57

RON BRECHER
AND SECOND PLACE GOES TO . . . In the
contest of competing Hercules globular star
clusters, M92 places a solid second to M13.
About 4,000 light-years farther away, M92 is
smaller than the Great Hercules Cluster and
not quite as bright. However, M92 has strong
visual appeal because of its angular outline
and compressed core.
southwest of Iota. Working from my
suburban yard, I can spot the cluster as
a fuzzy " star " in the finder field, provided
I don't overshoot Iota.
M92 is certainly less prominent
than M13. However, at magnitude 6.5
and sporting a diameter of 14′, it's still
a substantial target. M92's brightest
members are magnitude 12.1, only
two-tenths dimmer than those of M13.
Even so, all the little differences add up.
Those dimmer, smaller aspects pose a
challenge for my 4¼-inch when it comes
to resolving M92 into stars. Moreover,
the core of the cluster is extremely
concentrated. It's a brilliant but singular
mass. Maintaining sharp focus
is crucial for teasing out any detail. A
9.8-magnitude star immediately east
of M92 is handy for checking focus,
though it's much less bright than the
guardians of M13.
In my smaller scope at 93×, the globular's
periphery is salted with very faint
stars, but the strongly condensed interior
resists resolution. In the 10-inch
Dob, that compact core packs a punch
since M92 is more strongly packed in
the middle than M13. Even at 218×, the
central region yields very few individual
points, but the halo resolves nicely. The
whole cluster is outlined by dim outliers
that give the cluster a slightly squarish
appearance. It's a pretty sight.
Faint Fuzzy
The last - and admittedly, least - of
the Hercules globulars is 9.4-magnitude
NGC 6229. This third entry is no
prize-winner - but, hey, it's one that
most casual observers don't even know
about, so why not give it a try? Though
relatively dim, the little fellow is easy
to find. Well, sort of. You might be
tempted to make a right-angle turn at
M92 and head northwest for 7°, hoping
you'll bump into NGC 6229. I tried that
once - and veered way off-course.
I think it's wiser to retreat to M13. A
line drawn from M13 through Eta Herculis,
aimed 7° north-northeastward,
passes less than 20′ west of a handy
finderscope star: 4.8-magnitude 52 Hercules.
A further 1.6° onward, the line
runs a mere 10′ east of NGC 6229. The
key part of the star-hop is 52 Hercules,
which is plainly visible in any finderscope.
I center that star in my telescope
then, using a low-power eyepiece, carefully
nudge my way the required extra
distance to NGC 6229.
There's no hiding it: NGC 6229 is
a wimp. It's almost three magnitudes
dimmer than M92, and its diameter
of 4.5′ is about three times smaller.
The brightest stars of NGC 6229 are
magnitude 15.5 and not visible in citybased
scopes like mine. Still, the feeble
Hercules Hits
Object
Type
M13
Σ2104
Σ2101
Σ2097
M92
NGC 6229
Globular cluster
Double star
Double star
Double star
Globular cluster
Globular cluster
fuzzball can at least be detected using
backyard instruments. In my 4¼-inch
at 54×, NGC 6229 appears much the
way M92 looks in 10×50 binoculars.
Viewed at 93× it now resembles M13 in
the same binos. In my 10-inch at 200×,
the cluster grows in size just enough to
reveal a brightening towards the middle.
I can't resolve any part of the cluster.
Two 8th-magnitude stars lined up
north-south immediately west of NGC
6229 aid high-power focusing.
Okay, you've seen what my scopes
reveal. Give these light Labors a go.
That strongman, Hercules, will thank
you for it.
¢Contributing Editor KEN HEWITTWHITE
first sighted M13 in the summer
of 1967 with his 4.5-inch Tasco reflector.
Mag(v)
5.8
7.5, 8.8
7.5, 9.4
9.4, 9.6
6.5
9.4
Size/Sep
20.0′
5.7″
4.1″
1.9″
14′
4.5′
RA
16h 41.7m
16h 48.7m
16h 45.8m
16h 44.8m
17h 17.1m
16h 47.0m
Dec.
+36° 28′
+35° 56′
+35° 38′
+35° 44′
+43° 08′
+47° 32′
Angular sizes and separations are from recent catalogs. Visually, an object's size is often smaller than
the cataloged value and varies according to the aperture and magnification of the viewing instrument.
Right ascension and declination are for equinox 2000.0.
sk yand tele scope .o r g * JULY 2024 57

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Sky & Telescope - July 2024

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