Sky Tour Podcast for December 2025

This month’s episode is sponsored by Celestron, manufacturer of high-quality telescopes and an industry leader in developing exciting optical products with revolutionary technologies.
*****
I’m Kelly Beatty of Sky & Telescope magazine, and tonight we’re going on a tour of the stars and planets that you’ll see overhead during December. First we’ll watch for some impressive shooting stars, track down Mercury before dawn, check in with Jupiter and Saturn, gaze at a tall tower of evening dazzlers, and spend some time with the Ghoul — a star that can’t decide how bright it wants to be. So bundle up, grab your curiosity, and come along on this month’s Sky Tour.
****
December is the month of the solstice, when the Sun appears farthest south in the sky. This term — first used in the 14th century — comes to us from the Latin word solstitium, meaning “Sun standing still.” Nowadays it signals the beginning of winter for those of us north of the equator, and summer for Australians. This year’s December solstice comes at 10:03 a.m. Eastern Standard Time on the 21st. If you have a chance, watch where sunset occurs on this date — that will mark the spot on the horizon where the Sun sets its farthest south for the entire year. 
Y’know, virtually every culture has celebrated the winter solstice as a seasonal “turning point,” a sign that brighter, longer days lie ahead. But none of them celebrate the solstice because it’s the longest stargazing night of the year. Hmph! The truth is that December is one of the best times of the year to watch the stars. For one thing, unlike much of summer, you step outside and the air just looks clean. And clean air makes the stars and planets easier to see. Then you factor in what this season has to offer overhead — which is a lot. And it gets dark early, by 5 pm in most places. Heck, I sometimes try to sneak in a little stargazing before supper.
But before we get to the stars and planets of this holiday season, let’s check on the Moon’s whereabouts. Full Moon comes early this month, on the 4th. It’s sometimes called the Full Cold Moon, for obvious reasons, and it can appear directly overhead — or nearly so — around midnight as it arcs across the sky. Last quarter follows on the 11th, and new Moon on the 19th. The lunar crescent returns to the evening sky after that, with first quarter falling on December 27th. As you’ll hear in a moment, these dates have a bearing on what’s arguably the best meteor shower of the year.
*****
The annual Geminid meteor shower peaks this month. Pretty much everyone knows about the Perseid meteors that arrive each August. But the Geminids are under-appreciated, because they often produce the year’s best meteor event. Ordinarily you can count on the Geminids to deliver maybe one meteor per minute from a really dark location, and these can often appear bright and intensely colored. 
This shower gets its name because the shooting stars you’ll see all seem to streak across the sky from the direction of the constellation Gemini. And it has a broad maximum, so those “shooting stars” can be appreciated over a few nights. But if you had to pick one night to brave the cold to watch them, go for either the 13th or 14th. By then the Moon will be past last quarter, rising after midnight, so it won’t wash out the evening’s faintest meteors. 
Gemini rises by about 7 pm, and the show should be well under way by 9 pm with the shower’s radiant, near the star Castor, about 30° high in the east. This is the spot from which all these meteors will seem to radiate as they flash all over the sky. 
Here’s a tip: You really don’t need to face Gemini for this — just look in whichever direction your sky is darkest, and that’s often straight up. You can park yourself in a comfortable chair or even lie flat and, heck, watch the show all night long if you want. Just make sure you dress very warmly.
Usually meteor showers happen when our planet plows though a stream of small particles shed by a comet that get spread out along its orbit over time. But in this case the source isn’t a comet — instead it’s an unusual asteroid, called Phaethon, whose orbit carries it to within 13 million miles of the Sun every 524 days. Wow!
*****
While you’re waiting for the Geminids to appear, or any other time this month in early evening, you can easily track down a couple of planets. The most obvious is Jupiter, a brilliant beacon that rises in the east a couple of hours after sunset. Next month the king of planets reaches opposition, when it will be situated opposite the Sun in the sky and look very slightly brighter. But even now it’s a dazzling addition to the late-evening sky.
The other bright planet to look for is Saturn, which looks much dimmer than Jupiter — but it’s not hard to find. At nightfall, it’s roughly due south and about halfway to overhead. If you still aren’t sure you’ve found it, head outside on the evening of December 26th, when a fat crescent Moon will sit about 3° to its upper right.
Now, there is one more planet you can hunt for this month, and that’s Mercury. In fact, early December offers your last and arguably best opportunity to spot this fast-moving planet. The only downside is that you’ll have to be up before dawn, roughly 6 a.m., to catch sight of it. That’s about an hour before sunrise. You’ll find it just above the southeastern horizon by about the width of your clenched fist at arm’s length. As dawn approaches, Mercury climbs higher but the twilight gets brighter.
*****
With all this planetary action going on, are there any stars worth viewing? You bet! We might be on winter’s doorstep, but the evening sky is still hanging on to some of the stars of summer. 
Look well to the upper right of where the Sun sets, about halfway up in the sky. That bright, icy-white star is Vega [VAY-guh], which is sometimes called the Summer Star because it rides high in the sky during the balmy evenings of July and August. To Vega’s left by about three fists is Altair, the brightest star in Aquila, the Eagle. Above Vega, by about 1½ fists, is a slightly dimmer star called Deneb. Vega, Altair, and Deneb are the corners of the Summer Triangle, and this is it’s last hurrah until we get well into next year.
Deneb forms the head of the Northern Cross, which stands more or less upright during the evening at this time of year. Do you see it? There are five main stars in this cross, which overall is about two fists tall. Deneb is brightest and at the top. Below it is a row of three stars, roughly the same brightness and more or less in a horizontal row. The middle one is called Sadr, Arabic for “the chest.” Down at the foot is Albireo, about half as bright as Sadr. And in between, along that line, are two more stars that are fainter still. If you can see all seven, you’ve got a decently dark sky. If all you see is Deneb, well, sadly, you’re dealing with an awful lot of light pollution.
*****
Now do an about-face so you’re facing east. Around 9 p.m. early in December, and by 7 p.m. at month’s end, you can take in five of the 10 brightest stars in the nighttime sky! Start low down by finding Orion and the easy-to-spot vertical trio of stars that mark his belt. The belt is flanked by Betelgeuse to its left and Rigel to its right. To Orion’s left by a couple of fists are the twins of Gemini, anchored by the stars Castor and, below it, slightly brighter Pollux. That’s the general area from which the Geminid meteors will seem to originate as they zip across the sky. And Jupiter, unmistakably bright, is to the lower right of Pollux.
Above Orion is Taurus, the Bull, whose angry eye is marked by the reddish superstar Aldebaran. Look a little more than one fist above Aldebaran for a fuzzy patch of light. This is the Pleiades, a tight little nest of stars. Sometimes they’re called the Seven Sisters. If you’ve got decently sharp eyesight, you’ll see that the six brightest stars of the Pleiades form a tiny dipper shape. Don’t confuse this with the real Little Dipper, which is much bigger and located due north in the sky.
To Aldebaran’s left is the bright star Capella. This is the alpha star in the constellation Auriga (aw-REE-guh or sometimes pronounced aw-RYE-guh), which you can make out as a broad, misshapen hexagon with Capella at its top. Now, Auriga has a split personality — he’s either a charioteer or a goat-herder, depending on whom you ask. Capella mean’s “she-goat”, and just to its right is a faint, narrow triangle of stars sometimes called The Kids, as in baby goats.
Continue upward from Capella by about two fists to spot a loose chain of stars, about two fists long, marking the mythical hero Perseus. He’s on his side right now, with his head to the left and his body extending for about two fists to the right. The brightest star in Perseus, called Mirfak, marks his chest. Let’s spend some time with this hero to track down a star called “the Ghoul.”
*****
In Greek mythology, Perseus beheaded by the monstrous Medusa, whose could turn someone to stone just by looking at her face. Perseus kept the head as a weapon, because it retained its ability to turn any onlooker to stone. And one eye of that head is marked by a star that Arabic skywatchers named Algol, meaning “head of the ghoul (or ogre).” In Hebrew folklore, it was known as the Devil’s Head. It’s also known as the Demon Star.
So how did Algol get such a bad rap? Today astronomers know that it’s actually a triple star system, and its two main stars orbit each other tightly. Every 2.9 days, the dimmer of this pair passes in front of its brighter companion and covers it. This eclipse causes Algol, from our vantage point, to abruptly dip to about a third of its usual brightness for several hours. And you can see this drop yourself, by eye, with just a little preparation and good timing.
First, look carefully at Perseus to identify Mirfak and Algol, which are about one fist apart. Algol is on the right. They’re almost the same brightness. But during the eclipses, Algol dims so much that it becomes much fainter than Mirfak. Instead, it’s a closer match to the ghoul’s other “eye,” just to its right.
Now, remember, these dimmings take place every 2.9 days, like clockwork, and often they occur during daytime or during the wee hours of the night. So here are two dates and times in December to get you started — I picked these because it’ll be evening all across the Americas. Ready? OK, on the 17th, mid-eclipse is at 10:28 p.m. EST, and on the 29th it’s at 9:45 p.m. If you can’t remember those, don’t fret: Just go to SkyandTelescope.org and search for “Minima of Algol” — that will take you to a handy online app that will calculate the right times for any future date.
*****
Let’s end the evening tour by looking a bit west of directly overhead — well above Saturn. Look for four medium-bright stars at the corners of a huge square that’s a bit bigger than the size of your clenched fist. That’s another asterism, called the Great Square of Pegasus, and it marks the body of a mythical horse that’s flying across the sky. But this isn’t much of a horse — it’s upside down as seen by us northerners, and it has no hindquarters. The neck and head extend westward from the square’s bottom corner, ending in the star Enif, an Arabic word meaning “the nose.”
If you’re lucky enough to have good, dark skies, and if there’s no bright moonlight, look past Enif, toward lower right, for a parade of four small constellations: 
Equuleus (eh-QWOO-lee-us), the Little Horse; 
Delphinus, the Dolphin; 
Sagitta (suh-GIT-uh), the Arrow; and 
Vulpecula, the Fox.
Each of these is marked by only 3 or 4 dim stars, so they might be a challenge to spot. You can always use the star chart in center of every issue of Sky & Telescope to help you track them down.
*****
That’s about it for this month. If you want more tips for viewing the night sky, including a free, interactive star chart for any time or date, check out our website, SkyandTelescope.org.
If you haven’t already subscribed, you can find Sky Tour on Apple Podcasts, Spotify, Stitcher, or wherever you listen. And please leave a rating or review! It will help others find the show. 
And if you want to explore the solar system and universe more deeply, please do check out the full line of binoculars and telescopes available at Celestron.com.
Sky Tour is a production of Sky & Telescope, a division of the American Astronomical Society, and is produced by me, Kelly Beatty.
Next month we’ll spend some time with the easy-to-spot constellations Cassiopeia and Orion. Until then, I wish you clear skies.