Hosted by Chris Beckett & Shane
Ludtke, two amateur astronomers in Saskatchewan who
enjoy teaching astronomy classes and showing the public views
through their telescopes. actualastronomy@gmail.com
On Episode 547 of Actual Astronomy, hosts Chris and Shane guide
listeners through observing an array of August Messier objects
across the constellations Ophiuchus, Scorpius, and Sagittarius.
The show details viewing techniques for globular and open
clusters—highlighting targets like the egg-shaped globular M19,
the historical Ptolemy's Cluster (M7), and the beginner-friendly
M23. Additionally, they explore iconic Milky Way nebulae,
including the active star-forming Lagoon Nebula (M8) and the
nearby Trifid Nebula (M20) with its distinctive three-lobed dark
dust lanes.
1. M10 & M12 (Globular Clusters in
Ophiuchus)
- Binoculars: Sweeping through central Ophiuchus reveals these
two bright globulars in the same binocular field. They appear as
soft, distinct bluishgray spheres.
- Telescope: In an 8-inch telescope, M12 resolves well into
individual stars across its core, while M10 appears somewhat more
tightly packed, brighter toward the center, and slightly fuzzier
at the edges.
- Compare the two side-by-side: Despite being located near each
other in our sky, M12 has lost a significant portion of its
lower-mass stars due to repeated passages through the Milky Way’s
dense galactic disk.
2. M107 (Globular Cluster in Ophiuchus)
- Binoculars: A challenging target for binoculars; requires dark
skies and averted vision to spot as a minute, faint smudge.
- Telescope: Small-to-medium telescopes reveal a delicate,
somewhat un-concentrated patch of light with a loose core.
- M107 contains noticeable dark dust lanes or obscuring regions,
which is relatively rare for a globular cluster, giving it a
unique visual texture in medium-to-large scopes.
3. M9 (Globular Cluster in Ophiuchus)
- Binoculars: Similar in scale to M107, though slightly brighter
and easier to catch in 10x50s on a clear night.
- Telescope: Small scopes show a bright, unresolved central
nucleus surrounded by a faint, grainy halo.
- M9 is located remarkably close to the Galactic Centre—only
about 5,500 light-years away from it. It lies near dark nebulae
like Barnard 64, making the surrounding starfield visually
compelling.
4. M19 & M62 (Globular Clusters in
Ophiuchus)
- Binoculars: Separated by about 4 degrees, both fit easily into
a standard binocular field of view south of M10/M12. They look
like round, soft patches brightening toward their centers, with
M19 appearing noticeably brighter.
- Telescope: Smaller telescopes show compact, fuzzy disks.
Moderate magnification begins resolving outer stars on both.
- M19 is famous for being one of the most distinctly oblate
(egg-shaped) globular clusters known, likely due to tidal forces
from its proximity to the galactic core.
- M62 has an asymmetric core, heavily deformed by galactic tidal
forces, and hosts a rich population of millisecond pulsars.
5. M6 (The Butterfly Cluster) & M7 (Ptolemy’s
Cluster) Scorpius
- Naked Eye: Both are bright and obvious to the naked eye under
dark skies near the "stinger" of Scorpius.
- Binoculars: Binoculars provide the absolute best view. Both
clusters fit together in a wide 10x50 field. M7 is larger and
brighter; M6 displays a striking butterfly-like star arrangement.
- M7 is one of the oldest recorded deep-sky objects, noted by
Ptolemy in 130 AD.
- The orange giant star BM Scorpii, which sits on the wing of the
"Butterfly" in M6 and adds a nice pop of stellar color contrast.
6. M8 (The Lagoon Nebula) Sagittarius
- Naked Eye: Appears as a distinct, hazy patch in the Milky Way
band above Scorpius.
- Binoculars: Shows as a huge, glowing oval patch—larger than the
full Moon—with several bright stars embedded within it.
- Telescope / Filters: A UHC or O-III filter enhances the dark
dust lane ("the lagoon") bisecting the bright nebulosity.
- M8 is an active star-forming region containing Bok globules
(collapsing clouds of protostellar gas) and the famous "Hourglass
Nebula" region at its core.
7. M20 (The Trifid Nebula) Sagittarius
- Binoculars: Located just 1.4 degrees northwest of M8. Appears
as a faint, ghostly glow surrounding a central triple/multiple
star system.
- Telescope: Medium scopes under dark skies reveal the dark dust
lanes splitting the bright emission portion into three distinct
lobes.
- M20 is a rare "triple threat" nebula containing an emission
nebula (red in photos), a reflection nebula (blue in photos), and
a dark dust lane network (Barnard 85) that gives it its name.
8. M21 (Open Cluster) Sagittarius
- Binoculars: Situated right next to M20. Appears as a small,
compact, bright knot of stars.
- Telescope: Low-power views easily resolve 20–30 stars packed
tightly together.
- The "Trifid Trio": In wide-field eyepieces or binoculars, you
can view M8, M20, and M21 all in a single field of view, offering
one of the most spectacular Milky Way vistas available to visual
observers.
9. M23 (Open Cluster) Sagittarius
- Telescope: Low magnification is key. Small telescopes easily
resolve over 80–100 stars spread across a wide field in subtle
arc-like patterns.
- M23 sits against a rich background Milky Way star field, making
low-power wide-field views ideal. It is an excellent target for
beginners practicing star-hopping in northern late-summer skies.
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