What's Up Above? December Stargazing

Winter is here. In all fullness the shortest day and the longest night arrives on December 21st. Those living in the northern hemisphere at the dawn of humanity saw the autumnal Sun continue to fall in the sky in fear it would not return. The end was near. Yet, the winter solstice took place and the Sun did indeed return. They lit fires and torches. They danced and celebrated.

With this in mind, go outside any clear cold night this December. Look up. As you do, feel the skin on your face contract from the cold's touch; watch the condensation of your breath form a cloud to rise and dissipate. Permit the dancing pinpricks of light; jewels, big and small, in colors of brilliantly blue, sharp white, dim yellow, and soft copper to capture your awareness. Give way to the magic of the moment washing over you. When you do, feel a profound connection and lineage to your ancestors; and to those who looked up at the same stars in a deep December night with fear the Sun was going away and never coming back.

Then, out of nowhere a flash, streak, ignite, bomb! A meteor breaks through the serene scene. December is full of meteor showers, of major and minor classification, capable of radiating from anywhere overhead at any time of the night. Feel the Cold Full Moon all night long, while Jupiter, our benevolent god of the sky, reigns with Saturn in our celestial dome throughout the month.

Are you ready? Come outside with me and look up. Stargazing with your family and friends is a delightful way to celebrate our season of joy, hope, and promise. Our Sun returns. Here’s some of the best this December has to offer.

The Steed of the Sky: The Great Square of Pegasus, The entire month of December

Pegasus, the immortal winged horse in Greek mythology, is one of the children of Poseidon and Medusa. A mythological horse notoriously wild and free-roaming, was said to be so powerful that it created water streams when he struck his hoof on the Earth.

Our story begins when Perseus, the demigod offspring, being sent by King Polydectes to kill Medusa, the Gorgon. Using the polished bronze shield given to him by Athena he slays her, and from her severed neck Pegasus and Chrysaor emerge. The stallion of the night sky was finally tamed by the hero Bellerophon, after he was given a golden bridle by Athena to capture Pegasus. Bellerophon did so while the winged horse was drinking water by the Pierian Spring. On the winged horse, Bellerophon was invincible; victorious against all opponents, filling him with hubris. He believed he was more than mortal and thus belonged with the gods on Mount Olympus. On Pegasus' back, he rode upward, and this angered Zeus. He sent a gadfly to sting Pegasus which caused the horse to buck, throwing Bellerophon to Earth and to his death. The riderless Pegasus reaches Olympus where Zeus places him with his other steeds and tasks him to leading his thunderbolt chariot. For this service Zeus awarded Pegasus with a constellation that bears his name. Now, that’s a story.

This December, Pegasus rides directly overhead throughout the night. It is an unmistakable constellation identified by the four bright and similar magnitude stars forming the asterism of the Great Square of Pegasus. Check out the image above. An asterism is made up of the dots of stars and lines between to create a shape that describes what you see; in this case it’s a square. The key to identifying an asterism is that you are looking for stars that are the same brightness, or magnitude. When you find the Great Square, the upper right star is Scheat, and this is where the front legs of Pegasus are located. The lower right star is Markab, where the neck of our steed begins. The lower left star is Algenib, and the upper left star is Alpheratz. True, your eyes don’t deceive. Pegasus, indeed does ride through the night, upside down. Say what? Oh, and the star Alpheratz denotes the beginning of the constellation Andromeda, our chained princess. Ah, and that’s another story for another time.

 A Cold Winter Full Moon, December 4^th 

This month’s Full Moon is called the Cool Full Moon, amongst many other labels, as it rises during the longest, coldest, darkest period of the year. Throughout history for our North American first people and our European brethren, the December Full Moon is significant. One of the oldest observations of the event involved the early Celtics calendar aligning with a period of Alban Arthan (Light of Winter) observing the rebirth of the Sun and the time when the Oak King defeats the Holly King, returning light to the land. For the Mohegan people of North America, the Cold Full Moon, begins the time when families gather. Elders share stories, wisdom, and lessons with the children of endurance during dark times. I like this lesson.

What about the astronomy of this month's Cold Full Moon? The December Full Moon is the last of three supermoons to occur this year. More so, 2025’s supermoons were consecutive, three in a row. A supermoon is a term used to describe when the Moon is both full and at or near its closest point to Earth in its orbit. This point, or moment is called perigee. The average the Moon orbits the Earth is 238,855 miles. The Cold Full Moon this year is approximately 17,000 miles closer. The geometry of the Cold Full Moon is extreme. When the Moon is full, it is said to be at opposition to the Sun. Plus, in the northern hemisphere, during winter the Sun is at its lowest in the southern sky, thus the Moon is at its highest altitude in the sky; of any of the Full Moons throughout the year.

Even more, as the Sun sets at its earliest, the Full Moon rises at its earliest giving us one of the longest Full Moon nights. And the December Cool Full Moon is often the brightest of the year. This is because cold air holds less moisture, which means less of the Moon’s light scatters as it enters Earth’s atmosphere and gives us a crisper looking, brighter Moon.

When you spy the December Full Moon rising over the eastern horizon this month you may perceive a bigger, brighter, closer Moon than usual. This is your perceiving process playing tricks on you. How? When the Moon is low on the horizon your brain compares it to the surrounding objects, as is the case with the trees in the above image, and it tells you “Holy cow, that Moon looks HUGE!” As the night progresses and the Moon gains altitude, it appears smaller which is due to there being no reference for your brain to compare and contrast.

Want to test this for yourself? Try this. Get out and look at the Moon as it comes into view about the horizon. Extend your arm out towards the Moon, turn your thumb up, and compare the width of your thumbnail to the width of the Moon. Later, after the Moon rises higher in the night sky, get outside and take the same measurement. Your thumbnail covers the same amount. You see, that sometimes, “seeing isn’t believing.”     

Geminids Meteor Shower:  Peak December 14^th 

The annual Geminids meteor shower is a major meteor shower and is active from the 4th through the 20th of December. For 2025, the shower peaks on December 14th. The meteor shower radiates within the constellation Gemini (see above) and your chance to see meteors is any time the constellation Gemini is above the horizon. Plus, this year Jupiter will show you the way as it is the brightest, biggest point of light in the sky at that time, in that direction.

The Geminids is a class I meteor shower. A meteor shower class is a measure of how productive the meteor shower is and to be a class I the shower has to reliably display more than 10 meteors per hour. The parent body responsible for the Geminids is asteroid 3200 Phaethon. This year it is estimated that at the peak, the zenithal Hourly Rate (ZHR) will be around 100 - 120 meteors per hour. That’s a ton-o-meteors. Look for the constellation Gemini to rise above the east-northeastern horizon after 5:30pm local time. The opportunity for you to see the most meteors is after Gemini has risen highest in the sky around 2am.

This year’s Geminids are going to be great, as the Moon is 24 days old meaning our solar system’s street light is in its waning crescent phase and will rise above the horizon late allowing you to view fainter meteors which normally would be washed out by moonlight. As is the case with most meteor showers, they are best viewed around midnight due to the Earth’s rotational angle into the meteor stream. This year the predicted best time to view the shower is at 2am local time. Mark your calendar now because all of the meteor gazing conditions line up in our favor for a great show. While this time is considered the best time to view the shower, meteors can come from anywhere in the sky at any time.

Gather the family, bundle up, and get outside for 10 minutes to see some streakers, tracers, smokers, flares, sparkers, bolides, bursters, gliders, poppers, and train-makers. Get out and look at the Geminid meteor shower. I guarantee It will bring you merriment, and fill your heart with holiday joy.

The Winter Solstice:  December 21^st   

This is the day when the Sun’s solo annual sojourn stops its southern slide at what is known as the winter solstice. This year, the winter solstice occurs on December 21st at 8:04am. It is the moment when the Sun reaches its most southern point in the sky, in the constellation of Capricornus, and it is the first day of winter in the northern hemisphere. The good news is hence the solstice, the Sun now begins its return to the northern hemisphere.

Conversely, in the southern hemisphere, the Sun is above the horizon for longer than on any other day of the year. Thus, their first day of summer. All this happens because of the Earth’s angle on its axis, tilted at an angle of 23.5° to the plane of its orbit around the Sun. As this angle is fixed throughout the Earth’s orbit, sometimes the Earth's north pole is tilted towards the Sun (June), and at other times it is tilted away from it (December). That time is now. Take heart, daylight lasts a little bit longer. Don’t forget, longer night time means more time for stargazing! Sadly though, the Sun’s return journey doesn’t necessarily mean it’s warmer at night for us up here in the north.

Ursids Meteor Shower:  Peak December 22^nd  

Another major meteor shower in December is the Ursids meteor shower. See them streak through the night from December 17th through December 22nd. That’s correct, this shower overlaps with the Geminids. At their peak, the Ursids usually produce around 10 meteors per hour. This year, it is predicted to be 7 meteors per hour. The shower is expected to reach peak activity on the 22nd around 9am local time. The shower is visible from sunset to sunrise because the constellation Ursa Minor (Little Dipper) is circumpolar. It rotates around the northern hemisphere’s celestial North Pole, the star Polaris. Oh, and the end of Little Dipper’s handle is Polaris. So to find the radiant point, look north. The later in the evening / early morning you look, the higher the radiant point is in the northern sky. A benefit of this shower is you don’t have to crane your neck and stare straight up to see the radiate point. Assume a comfortable position and enjoy. Remember, that meteors can radiate from anywhere in the night sky, so keep a keen eye and a wide, panoramic view.

Update: Don’t Call Us Minor! Monocerotids, Coma Berenicids, December Cassiopeid, and December Leonis Meteor Showers:  The entire month of December

Meteor showers are categorized into classes. The Geminids and Ursids are Class I, while the Monocerotids (Dec. 5 – 20), Coma Berenicids (Dec. 12 – 20) are Class II, while the December Cassiopeid (Dec. 1 – 8), and December Leonis (Dec. 5 – 24) are Class IV. A class is determined by the shower’s ZHR, the Zenith Hourly Rate. That is the average meteors visible per hour if the radiant is directly overhead. The “if” in that last sentence is important since a significant portion of all meteor showers’ have radiant points that are not even close to being overhead as it traverses the celestial dome.

A Class I meteor shower is a ten or better ZHR. Remember that the name of the meteor shower denotes the specific constellation where the radiant point for the meteor shower resides. It is the specific area within the constellation from where the meteors will emanate. That said, never forget that meteors can appear, streak, flash, explode, bolide, and smoke from anywhere and at any time in the night sky. Oh, the anticipation. Sort of like Christmas Eve, and what fun is that?

High above us this Christmas Eve night, Princess Andromeda will journey home upon the winged horse Pegasus with her hero Perseus at the reins. Accompanying them and creating an expansive parade across our holiday night sky is the Cold winter Moon, those mischievous sisters we call the Pleiades, the conspicuous King of the Sky, the planet Jupiter, as well as the planet Saturn, bringer of peace and abundance.

Indeed, a splendid seasonal gathering on their own, yet major and minor meteor showers will add to the merriment at every unexpected moment and turn. Together they create quite a festive celebratory celestial dome. (Personally, I think all this merriment and festiveness is due to those seven sisters that make up the open star cluster we call the Pleiades returning to the night sky. Heck, they’re the ones that organize all the parties around the world celebrating the return of the Sun at the Winter Solstice. I knew it.)

Just step outside in December, for however brief a moment it is and look up. Embrace the unique immersion of the darkness found inside this special time of year. There are truly many many magical moments overhead for you and your loved ones to behold.

As a child, I would stay up late on Christmas Eve. Lying in my bed I’d stare up in wonder, through a frosted bedroom window, at the stars on the other side. That night when sleep never arrived, viewing the stars filled my heart. I hope they do for you too when you look up and see our wonderful expansive universe. Consider this a gift to you from the cosmos.

Season’s greetings, happy holidays, and forever clear skies to one and all!