The planets
Mars is leaving the evening sky. Don’t expect to see it this month and next. It’s heading for conjunction with the sun on January 10.
Saturn is high on the eastern side of the celestial dome at dusk for most observers as the month starts. The ringed planet is at quadrature on the 17th, so it will be right about on the meridian at dusk mid-month. And then it’s high up on the western side of the celestial dome at month’s end. Saturn is within the boundaries of Aquarius all month, but slowly heading for the boundar with Pisces as it hangs a little south of the southwestern fish head.
Neptune is somewhat close to Saturn. Neptune is retrograde until the 10th and then resumes direct motion. All month, it’s close to a double star with HD 224510 as one of its names. The star’s about 360 light years away. Meanwhile, the light from Neptune takes just four hours, seven minutes to get to us. To us, they appear just 3.5 arcminutes apart on and about the 7th. Of course, you need magnification and a lot of light gathering power to see both. Neptune’s about magnitude 8. The double star is about magnitude 12.5.
Uranus is in Taurus near the Pleiades, retrograde all month. It passes just 6 arcminutes from the star 14 Tauri, which is about 395 light years away, on the 13th.
Jupiter spends all month in Gemini. It’s retrograde on the eastern side of the constellation and heading toward the star Wasat. The planet will be at opposition next month, so it’s up nearly all night now and rising earlier each evening.
Fast-moving Mercury starts the month in Libra. Greatest elongation is on the 7th at 20.7° west of the sun. On the 14th and 15th, you may spot it near Graffias in Scorpius. On the 18th, the messenger planet has entered Ophiuchus and is getting harder to see because it’s rising much closer to sunrise. You might catch a glimpse of Mercury barely above the horizon before dawn’s glow is too bright if you’re near the equator as the month ends. The planet has just entered Sagittarius then.
If you can see Venus this month, it will probably be from around 9° north, close to sunrise, and early in the month. The planet is heading for superior conjunction on January 6. Then it will become the legendary evening star for most of 2026.
The moon
On its circuit this month, the moon occults the Pleiades on the 4th. It’s full the same date and at perigee at 356,900 kilometers.
The Pleiades occultation will be a northern hemisphere event. Depending on where you watch from, the moon will hide different stars. From around 55 to 60 degrees north, the moon will go right through the middle of the kite-shaped asterism. From closer to the equator, the moon will graze the cluster on the north side. And in the Arctic, the moon will go through the southern part of the seven sisters. Of course, if you’ve ever seen the Pleiades in binoculars or a telescope, you know there are many more stars among and around those visible to the naked eye.
The Pleiades cluster has more than a thousand stars. They extend far enough, some people in the southern hemisphere will get an occultation of some Pleiades, just not the ones we can see easily without optical aids. And this occultation will be a bit hard to see even for the naked eye stars, since the full moon is so much brighter. The stars fade into the moonglow before we can see them instantly disappear as the moon’s disk covers them. But it’s going to be fun to look anyway. To minimize eye fatigue, use a filter to dim the moon’s light. Yes, that will dim the star’s light too, but that’s just something we have to deal with.
Northern lunistice is on the 5th at 28.3° north.
The moon passes by Pollux and Jupiter in Gemini on the 7th. On the 10th, a day before the moon’s at last quarter, it occults Regulus. Northern Canada and Greenland get the occultation.
Luna crosses the equator southward on the 12th. On the 17th, it’s at apogee, 406,300 kilometers away. The thinning crescent can be a guide to finding Mercury on the morning of the 18th. Southern lunistice is on the 19th at 28.2°. New moon is on the 20th. The moon would appear closest to Mars that evening, if not for Mars (and likely the moon also) being lost in the evening sunset glow.
The moon’s at first quarter and goes north over Earth’s equator on the 27th. You’ll see it nearest Saturn in the evening sky around that time too.
And then we have another Pleiades occultation on the 31st. This is also a northern hemisphere event.
Meteor shower
Under ideal conditions, you could see 120 Geminids per hour at their peak about December 14th. You don’t necessarily need to stare at Gemini to wait for meteors. While their tracks seems to go back to a spot near Castor, they might not light up until they’re partway across the sky. The bits of dust that produce Geminids come from an asteroid named 3200 Phaethon. Scientists are still studying just how they come off the asteroid.
Solstice
Earth’s southern solstice is on December 21st at 15:04 Universal Time. This is when the southern hemisphere daylight periods and the northern hemisphere nighttimes are the longest.