Howdy Star Gazers and welcome to this episode
of Star Trails. Drew here and I'll be your guide
to the night sky for the week starting May 18th
through the 24th. This week the moon wanes and
the early morning sky comes alive. We'll also
take a journey back into history and learn about
one of the largest constellations in the sky,
and why it doesn't exist anymore. Also, did you
know there was once a house cat in the sky? More
on that later. Whether you're tuning in from
the backyard, the balcony, or just your imagination,
I'm glad you're here. So find a cozy spot, let
your eyes adjust, and let's see what the sky
holds for us this week. Let's start with the
moon. On May 18th, it's in a waning gibbous phase,
still bright in the sky but shrinking each night.
By the 20th, we hit the last quarter, meaning
the moon rises around midnight and leaves us
with dark skies after it sets. And by the end
of the week, we're deep into the waning crescent
phase, which means prime conditions for hunting
faint galaxies and star clusters. Now onto the
planets. In the evening Jupiter is hanging low
in the western sky after sunset. It's getting
closer to the sun's glare each night, so catch
it while you can. Mars is much easier to spot,
glowing reddish high overhead after dark. It's
a great target this week, especially with less
moonlight to compete. If you're an early riser,
the morning sky has even more going on. Venus
is blazing away in the eastern pre -dawn hours.
It's the brightest thing in the sky other than
the moon. Look above it and you'll find Saturn,
more subdued but still visible without a telescope.
And just before sunrise, try spotting Mercury.
It's hugging the eastern horizon and can be tricky,
but it's worth the challenge. Meanwhile, spring
constellations are still putting on a show. Look
south for Virgo and Leo, or trace the arc of
Boötes, where bright orange Arcturus anchors
the view. This is also a fantastic week to aim
for deep -sky gems like M13 in Hercules or M5
in Serpens, especially now that the moon isn't
hogging the spotlight. Before we get into the
second half of the show, I have a little housekeeping
to discuss. As we end May and head into summer,
astronomy starts becoming difficult for many
of us. Moving towards the summer solstice, the
days will grow much longer, affording us less
observation time. Increased heat and crazy summer
weather can be a problem for some of us. For
example, here in the southeast U .S., summer
brings haze, humidity, and daily thunderstorms.
Not to mention 90 degree temperatures, mosquitoes,
and other pests. So all this to say, I won't
be doing a lot of observation for the next 3
or 4 months. I haven't decided if the show will
continue to be weekly during the summer or whether
I'll try releasing every 2 weeks. If you have
any opinions on this, go to StarTrails .Show
and let me know. Also, last year, right before
our December break, I mentioned that I would
be reading Nightwatch, a practical guide to viewing
the universe, by Terence Dickinson. This is a
popular book for backyard astronomers. Well,
sadly, I never got around to reading it, so I
apologize to anyone who was hoping for a Star
Trails book club moment. I do plan to start reading
it soon, especially since observation will be
rough for me in the coming weeks. I'll report
back with my thoughts on this book in a future
episode. This book is often cited as a must -read
for backyard astronomers, so be sure to get the
fifth edition, which is the latest version. Today
we're going to discuss some constellations of
the southern sky. Regular listeners know that
we generally focus on the skies over North America,
so this may be unfamiliar territory. I was once
told by an astronomer that the southern hemisphere
wasn't as impressive as the northern. He said,
and I quote, all they have are some Magellanic
clouds. This couldn't be farther from the truth.
I once spent several weeks in Australia, and
one night in the country I was able to see a
stunningly dark, clear night sky filled with
dazzling, unfamiliar patterns. While the northern
sky is home to some of the most iconic and familiar
constellations, like Ursa Major, Orion, and Cassiopeia,
it offers a more edge -on view of the Milky Way.
That means we see a thinner, less dense section
of our galaxy, but it's rich in recognizable
shapes and nearby objects like the Andromeda
Galaxy and the Pleiades Cluster. Polaris, the
North Star, also makes navigation easy, and centuries
of mythology have helped etch these constellations
deep into cultural memory. But head south and
the sky explodes with drama. The Southern Hemisphere
gives us a direct line of sight to the galactic
core, where the Milky Way appears brighter, denser,
and far more intricate. It hosts the Southern
Cross, the dazzling Carina Nebula, which we'll
discuss in a moment, the massive Omega Centauri
Cluster, and even entire satellite galaxies,
the large and small Magellanic Clouds that my
astronomer friend was so dismissive of. The reason
I mention this is because the southern sky was
home to a fascinating constellation that doesn't
exist anymore. There's actually a whole cast
of constellations that used to exist and don't
anymore. And none of them were quite as grand
or as doomed as Argo Navus, the ship that got
sunk by astronomers. This was once a constellation
so big, so sprawling, it had to be broken up
like a decommissioned schooner at a shipyard.
Argo Navus was named after the mythical ship
Argo, the one Jason and the Argonauts sailed
on during their legendary quest for the Golden
Fleece. This is classic Greek mythology. The
constellation was first catalogued by Claudius
Ptolemy in the 2nd century CE, during the golden
age of ancient astronomy. Back then, they weren't
too concerned with how huge this thing was. It
sprawled across a massive chunk of the southern
sky. To give you an idea of its size, if you
took Orion, Canis Major, and Gemini, and smashed
them all into one mega constellation, that's
the scale we're talking about. For centuries,
Argo Navus stood as the largest single constellation
in the sky, but it had a problem. Simply, it
was really, really impractical. By the 1700s,
astronomers started to feel like Argo Navis was
less of a constellation and more of a mess. It
had hundreds of stars and no clear borders. Trying
to map or reference anything inside it was like
trying to navigate a ship with three captains
shouting different directions. Enter Nicolas
-Louis Delacay, an 18th century French astronomer.
He was mapping the southern skies from the Cape
of Good Hope in South Africa. In 1763, Lakai
decided enough was enough. He chopped Argo Navus
into three new nautical -themed constellations,
and they've stuck ever since. There's Carina,
the keel of the ship. Pupus, the stern, also
known as the poop deck, and Vela, the sails.
And just like that, the mighty Argo Navus was
no more. Of course, just because the name disappeared
doesn't mean the stars did. These three new constellations
inherited all kinds of celestial treasures. Carina
is home to Canopus, the second brightest star
in the night sky, just behind Sirius. For viewers
in the Southern Hemisphere, Canopus is a brilliant
white beacon low on the horizon. Deep in Carinna
lies the Carinna Nebula, one of the largest star
-forming regions visible from Earth. Inside it,
we find the massive and unstable Etta Carini,
a binary star system so volatile it once brightened
the sky in the 1800s to become the second brightest
star for a time. Let's drift over to Vela. Its
most famous feature is the Vela Supernova Remnant,
a massive bubble of gas and dust left behind
by a star that exploded about 11 ,000 years ago.
Its ghost is still expanding through space. Inside
the remnant is the Vela Pulsar, a rapidly spinning
neutron star beaming out radio waves like a cosmic
lighthouse. Pupus is home to Messier 93, an open
-star cluster tightly packed with hot young stars.
There's also NGC 2467, a vibrant nebula sometimes
called the Skull and Crossbones Nebula. Despite
its eerie nickname, it's actually a stellar nursery.
So even though Argonavis, as a name, is gone,
its pieces are alive and well. filled with some
of the most dazzling and active regions of the
Milky Way. Of course, Argo wasn't the only constellation
to get the axe. Here are a few other sky figures
that were edited out of the final draft. Quadrons
Morales was a northern hemisphere constellation
created in the 18th century and named after a
wall -mounted astronomical instrument, the quadrant.
It no longer exists officially, but its name
survives in the quadrantid meteor shower that
peaks in early January. Felis, the cat, was a
house cat in the sky. It was introduced by French
astronomer Joseph -Jérôme de la Londe in 1799
because, as he put it, cats deserve to be represented.
The IAU disagreed and poor Phelous got booted
in 1922. The constellation was located near Hydra.
While it's not acknowledged anymore, its brightest
star, Phelous, is a reminder that it existed
and is quite an interesting star in its own right.
Located more than 600 light years from Earth,
Felis is an orange -red giant with a high proper
motion. That's the apparent movement of the star
compared to others in the sky. And finally, Antinous
is another constellation that was quietly retired.
A tragic figure from Roman history, Antinous
was Hadrian's young lover. He was later deified
and immortalized as a star pattern. The constellation
was removed from charts in 1922 and became part
of the constellation Aquila. More recently, the
IAU working group on star names approved the
name Antinous for the star Theta Aquili in 2024
in honor of the defunct constellation. If there's
any lesson here, it's that the sky is always
evolving. constellations aren't permanent. They're
cultural artifacts shaped by who we are, what
we believe, and how we explore the universe.
They remind us that the tapestry of the cosmos
is a mirror of our evolving time here on Earth.
If the stars spoke to you this week, or if a
question's been on your mind, I'd love to hear
it. visit our website, StarTrails .Show, where
you can contact me and explore past episodes.
Be sure to follow us on Mastodon, Blue Sky, and
YouTube. Links are in the show notes. Until we
meet again beneath the stars, clear skies everyone.