Howdy Stargazers, and welcome to this episode of Star Trails.
I'm Drew, and I'll be your guide to the night sky for the week starting October 20th to
the 26th.
This week brings meteor showers, conjunctions, some classic deep sky objects, and of course,
a comet that has everyone talking.
We'll complete a celestial family drama that played out in Greek mythology, and later in
the episode we'll talk about the scourge of stargazers, light pollution, and what we can
do about it.
So grab a comfortable spot under the night sky, and let's get started.
Comet C 2023 A3, also known as Shushin Shin Atlas, is currently one of the most exciting
celestial objects in the sky.
It reached its closest approach to Earth on October 12th, and will remain visible in the
evening skies throughout this month.
Look for it around twilight, shortly after the sun sets, and make sure you have an unobstructed
view of the western horizon.
The comet is steadily climbing higher each night, making it easier to observe as the
days progress.
By October 26th, it will be about 38 degrees above the horizon.
That's about the height of four fists held at arm's length to the sky.
And it sets roughly four and a half hours after sunset.
During this period, the comet's tail is expected to become more prominent, stretching dramatically
as it moves further from the sun.
If you're in a location with dark skies far from city lights, you may even spot some
detailed features of the tail.
While binoculars or a small telescope will enhance your view, it may also be visible
to the naked eye in optimal conditions.
This period may be the best chance to observe this comet, as it won't return for tens of
thousands of years.
The moon will be rising later in the evening this week, which may prove useful for comet
spotting.
I went out and photographed comet A3 a few days ago, and I can confirm it's a spectacular
object, visible even in the light of the full supermoon.
With averted vision, I was barely able to make it out, but it jumped out of the sky
in my 11x70 binoculars.
I was able to photograph it using an iPhone in night shot mode, and it looked great at
200mm when photographed with a full-frame, mirrorless camera.
It took me two tries to spot A3.
My first effort went horribly awry as I attempted to locate it against the bright backdrop of
metropolitan light pollution near my home.
But since we've had consecutive clear nights lately, I decided to try spotting it the next
evening, but this time I drove about an hour into one of the most desolate counties in
my state, to a location where I've had good success shooting the Milky Way in the past.
Lens still weren't great.
I was fighting against both the brilliance of the full supermoon and time.
The comet was low in the sky.
I estimated it was about 10 degrees above the horizon by the time I arrived, so it wasn't
going to hang around long for photos.
I put my camera on a tripod and found an old barn to place in the foreground for some wide
shots.
Then I switched to a 200mm lens for a closer view, and before I left, I placed my iPhone
on a tripod to see how those would turn out.
I discovered that if you're in a reasonably dark area, a steadily held smartphone using
a night shot or astronomy mode can easily capture this comet.
Although I did manage to eke out a few images, I won't be entering these into a competition
or even sharing them on social media.
I plan to make another effort in the coming days, provided we have clear skies, and I
encourage anyone listening to go out and see this comet now before it's too late.
The last time I saw a comet this spectacular was Haley's Comet in 1985 when I was just
10 years old.
A3 is really that good, so go get your eyes on it if you can.
And not to be captain obvious here, but the darker the skies, the better your view will
be, and that goes for every object in the night sky.
In the second half of the show, I'll tell you how you can find the darkest skies in
your neck of the woods.
But first, let's find out what else is happening in the sky this week.
The last quarter moon is on October 24th, so you'll see half of it illuminated, rising
late at night and setting in the early afternoon.
Before that, on October 20th and 21st, keep an eye out for a nice conjunction of the moon
and Jupiter.
As the second brightest planet in the sky, Jupiter will shine brightly next to the moon
all night long.
By the end of the week, on October 26th, the moon will also be hanging out with Regulus,
the red heart of the constellation Leo.
This early morning pairing will be a great way to start your day just before dawn.
Jupiter will be visible all night long, hanging out in Taurus.
As I mentioned, you'll see it in conjunction with the moon on the 20th and the 21st, but
it will be shining brightly throughout the week.
Saturn is situated in the constellation Aquarius and is a perfect target for telescope viewers,
especially with its rings becoming more edge-on as we head into 2025.
You'll spot Mars rising in Gemini later at night, around midnight by week's end.
On the night of October 23rd, it will also pass close to the moon, another conjunction
worth checking out.
Meanwhile, Venus, our bright evening star, will be glowing low in the southwestern sky,
especially around October 24th when it appears next to the bright red star Antares in Scorpius.
Don't forget the Orionid meteor shower, peaking tonight and into the morning.
These meteors come from Haley's Comet and shoot across the sky at 41 miles per second.
Be aware the moon will be quite bright during the peak, which means it may drown out some
of the fainter meteors.
Try to block the moon behind a tree or building and focus on the darker parts of the sky.
Later in the week, the Leonis-Manorids meteor shower peaks on October 24th, but these are
a bit quieter, with fewer meteors per hour.
For deep sky enthusiasts, the Perseus double cluster will be well positioned in the northern
sky on October 26th.
This duo of open star clusters NGC 869 and NGC 884 are about 7,500 light-years away,
and you can find them nestled between Perseus and Cassiopeia.
Even with just binoculars, you'll be able to see this rich field of stars sparkling
against the darkness of space.
Also well placed this week is the Andromeda Galaxy, our nearest galactic neighbor.
At about 2.5 million light-years away, it's the largest galaxy visible from Earth and
can be spotted with the naked eye if you're in a dark area.
You'll find it in the constellation Andromeda, rising higher in the sky as the night goes
on.
And for telescope users, the Triangulum Galaxy M33 is another great target.
It's the third largest member of our local group of galaxies and offers a beautiful spiral
structure for those with larger scopes.
You'll find it in the small constellation Triangulum, which is located roughly between
Andromeda and Aries.
Lastly, don't miss the Pleiades, or Seven Sisters star cluster.
This open cluster in Taurus is always a breathtaking sight, and it will be visible in the eastern
sky.
A prominent constellation that rises this time of year is Cepheus, the king.
If he sounds familiar, it's because he's been a big player in some of the night sky
lore we've discussed recently, particularly in the stories of Andromeda, Cassiopeia, Cetus,
Pegasus, and Perseus.
Right near the constellation's Cassiopeia and Draco, Cepheus is best seen in the northern
sky during the fall and early winter months.
It's easily identifiable by its house shape, a five-sided figure that somewhat resembles
a child's drawing of a house with a peaked roof.
The constellation contains several notable stars, including Alderaemon, the brightest
star in Cepheus, and Delta Cephe, which has been critical in the study of variable stars.
In fact, Delta Cephe is the prototype of Cephed variable stars, which astronomers use to measure
distances to far off galaxies.
Another highlight is the Garnet Star, a strikingly red supergiant that shines with a deep, ruddy
hue.
Cassiopeus also hosts IC 1396, an expansive star-forming region containing the Elephant's
Troncnebula, a favorite among astrophotographers.
According to Greek myths, Cepheus was the king of Ethiopia, and he was caught up in some
celestial drama after his wife, Cassiopeia, boasted that she was more beautiful than the
sea nymphs.
Cassiopeus angered the sea god, Poseidon, who sent a sea monster, Cetus, to ravage their
kingdom.
To appease Poseidon, Cepheus and Cassiopeia sacrificed their daughter, Andromeda, by
chaining her to a rock.
But the hero, Perseus, swooped in riding Pegasus to save her just in the nick of time, and
she ended up marrying him.
The entire family is immortalized in the night sky as constellations, with Cepheus often depicted
as a king on his throne or holding a royal scepter.
If you like fast cars, you've at some point probably heard the expression, there's no
replacement for displacement, meaning that you can bolt on a turbo or a supercharger in
various go-fast parts that boost an engine's power, but at the end of the day, the greatest
performance will come with more displacement, in other words, a bigger engine.
In astronomy, and especially astrophotography, there are tricks to pull dim objects from
light-polluted skies, such as techniques involving filters, exposure stacking, certain types
of cameras and computer processing.
But everything gets a lot easier to deal with, and viewing is much more enjoyable if you
can simply relocate to darker skies.
Today we'll talk about the Bordle Scale, which measures the brightness of the night sky based
on light pollution, and will get into practical ways you can still enjoy the stars even if
you live in a brightly lit area.
This light pollution scale was developed by astronomer John E. Bordle in 2001.
The scale ranges from 1 to 9, with 1 being the darkest, most pristine sky you could ever
imagine, and 9 being a sky flooded with artificial light, such as in the middle of a large city.
If you've looked at any astrophotography online recently, you'll often see the photographer
mentions the Bordle rating of the area where the photo was taken.
Knowing your rating can give you a great sense of what you'll be able to see from your location
or capture with your astrophotography rig.
Let's break down a few key levels of the Bordle Scale.
Bordle 9 is the worst of the worst.
Think of downtown in a major city like New York or Tokyo.
Here, you might only be able to see a handful of the brightest stars.
Forget about spotting the Milky Way or planets other than Venus or Jupiter, and you can't
see any deep sky objects.
Bordle 7 and 8 are suburban skies.
You'll see more stars than in the city, but the Milky Way is still a no-show.
You'll be able to spot a few planets and the brighter constellations like Orion in winter
or Scorpius in summer.
I live in a transitional zone between Bordle 7 and 8, just a few miles outside a metropolitan
area.
But still, with binoculars, I can spot star clusters and some major nebula, such as the
Great Nebula in Orion.
Bordle 4, 5, and 6 are rural skies, with varying degrees of light pollution.
In 5 or 6, you can start to see the Milky Way on a clear night, but it's faint.
As you move toward Bordle 4, the Milky Way gets clearer, and you might spot some of the
brighter nebula and the Andromeda Galaxy.
When I went out to photograph Comet A3 a few days ago, my location was in a Bordle 4 zone.
My local astronomy club's observation site is also located in Bordle 4.
Bordle 2 and 3 zones are considered truly dark skies.
You can see the Milky Way shining brightly, and if you have a telescope, you can start
tracking down faint galaxies.
Bordle 1 is the dream.
A truly dark sky where the Milky Way is so bright, it casts a shadow.
You can see thousands of stars, all the constellations, the zodiacal light, and even faint details
of nebula without any equipment.
It's the kind of sky you can find in remote deserts, high mountains, or far out at sea.
I live in a southeastern state where Bordle 4 is common in between small cities and a few
metropolitan areas.
In my experience, I typically need to drive about 30 miles away from my home location
to get truly dark skies.
In my state, we have a handful of small areas that are Bordle 3 or even 2.
So how can you determine what zone you're in and where some darker skies are?
My favorite resource is, of course, a website.
Visit lightpollutionmap.info and click anywhere on the map to get detailed information on
the sky brightness at that point.
Zooming out will give you an idea of where light pollution hotspots are, and I'll include
a link in the show notes.
If you're stuck in a Bordle 7 or 8 zone, there are ways to enhance your stargazing.
First up is reducing local light interference.
It sounds simple, but blocking out nearby street lights or house lights can make a big
difference.
These nearby light sources wreak havoc on your night vision.
And a spot where they aren't shining in your eyes.
Even moving just a few blocks away from bright street lights or heading out to a park or
field can make a difference.
If you can, seek out higher ground, hills or rooftops where there's less light reflecting
off nearby surfaces.
Filters are another tool in your kit.
Light pollution filters like a UHC that's ultra high contrast or a CLS, City Light Suppression
Filter, can help cut through some of the artificial light by blocking certain wavelengths, such
as those emitted by street lights.
These filters really improve the visibility of faint objects like nebula, star clusters
and galaxies, even in moderately light polluted areas.
Astrophotographers who live in areas with a lot of light pollution have devised some smart
techniques to deal with pollution.
As with visual observation, a broadband light pollution filter can be especially useful.
These selectively block the most common types of artificial light, like sodium vapor and
certain LED lights, which are the main culprits in city and suburban lighting.
You can also use narrowband filters, which only let through very specific wavelengths
of light.
These are useful for photographing nebula as they enhance the light emitted by ionized
gases while filtering out other types of light.
Another strategy for astrophotography is using a monochrome camera with narrowband filters.
Monochrome cameras, as the name suggests, don't capture color the same way a regular
DSLR might.
They essentially shoot black and white images, so you have to use red, green and blue filters
to create the layers for an RGB image.
There are other useful filters for monochrome cameras too.
By capturing different wavelengths separately, usually hydrogen alpha, oxygen 3, and sulfur
2, you can build up a detailed high contrast image even in areas with significant light
pollution.
After capturing each filter's data, you can stack the images in image processing software.
This technique is a favorite among astrophotographers who shoot in urban areas because it allows
you to essentially exclude the wavelengths you don't want to capture, such as those of
light pollution.
Regardless of the camera used, image stacking is an essential technique for almost all astrophotography
nowadays.
By taking multiple long exposure shots and then using software to combine them, you can
increase the signal to noise ratio in your final image.
This helps to bring out faint celestial objects while minimizing the impact of light pollution.
Programs like Deep Sky Stacker or Pixensight are popular for this technique, and the results
can be stunning even from a city.
Light pollution doesn't just affect our ability to see the stars, it's also impacting
wildlife.
Artificial lights confuse animals that rely on natural light cues for navigation, migration,
and reproduction.
Birds, sea turtles, even fireflies can suffer from the excess light that we throw into the
sky.
So reducing light pollution isn't just about us as stargazers, it's about keeping nature
in balance too.
Some communities are adopting dark sky initiatives.
These efforts work to replace traditional street lights with shielded, downward-facing
lights, which reduce unnecessary outdoor lighting and promote even more efficient lighting
designs.
It's a win for the environment, energy use, and of course for stargazing.
That's it for today's episode of Star Trails.
If you found this episode informative or entertaining, please share it with a friend.
The easiest way to do that is by visiting our website, startrails.show, where you can
find all of our episodes, including transcripts, night sky maps, and more.
Until next time, keep looking up and exploring the night sky.
Clear skies, everyone!