What’s Up in the Night Sky – December 2025
from In-The-Sky.org
Moon Phases
First Quarter – November 28
Full – December 4 – Full Cold Moon
Last Quarter – December 11
New Moon – December 19
First Quarter – December 27
Close Encounters
November 29: The 9-day old Moon passes north of Saturn by a little more than 3°.
December 2: Comet C/2025 T1 ATLAS has its closest approach to the Sun. It is currently passing through Vulpecula, then Sagitta around December 5, then Aquila the rest of December.
December 3: The nearly full Moon passes less than a degree from the Pleiades star cluster. Too far apart to fit in telescope views but a nice binocular and naked eye view.
December 4 (early AM): Mercury reached dichotomy, reaching half-phase in the early morning sky.
December 6: Mercury reached its highest point in the sky this early AM, shining at magnitude -0.5.
December 7: The 17-day old Moon passes 3.5 degrees above Jupiter in the evening sky.
December 9: The Moon passes close below Regulus in Leo around Midnight.
December 14: Geminid meteor shower. See below.
December 15: The Orion Nebula reaches opposition and is visible all night.
December 18 (early AM): The thin crescent Moon passes 6 degrees south of Mercury just before sunrise.
December 21: The shortest day of the year occurs.
December 26: The almost-first quarter Moon passes within 3.5 degrees of Saturn.
December 31 (early AM): For the second time this month, the nearly full Moon passes less than a degree from the Pleiades star cluster. Too far apart to fit in telescope views but a nice binocular and naked eye view.
Major Meteor Showers – from https://www.amsmeteors.org/meteor-showers/meteor-shower-calendar/
The Southern and Northern Taurids begin around October 13, have a fireball peak around November 4, and ends around the first of December.
The Leonid meteor shower is active from November 6 through November 30 with peak activity on November 17. A maximum zenithal hourly rate of 15 may be reached under clear, dark skies.
The Geminid meteor shower is active from December 4 through December 17 with a peak activity around December 14. Under very dark and clear skies you could see as many as 120 meteors per hour. The Moon will be new so there will be no interference from moonlight.
The Ursid meteor shower is active from December 17 through December 26 with a on the night of December 21-22. The thin crescent Moon will set early and not interfere. Zenithal Hourly Rate is around 10.
Planet Watch for November 22, 2025
Mercury is becoming visible in the morning sky as it reaches its highest altitude on December 6.
Venus is about to pass behind the Sun. It will emerge and be visible in the evening sky where it reaches its highest point in June 2026.
Mars is about to pass behind the Sun. Mars reaches superior conjunction (when Mars is on the opposite side of the Sun from Earth) on January 9, 2026.
Jupiter rises around 10:30pm and is visible for the rest of the night. It shines in Gemini at magnitude -2.5 and reaches opposition on January 10, 2026.
Saturn is visible once the sky darkens and is visible until a little after Midnight. The southern faces of the rings are coming into view, still tilted at about a 3.5° tilt from our vantage point. The ringed planet shines at magnitude 1.0 in Aquarius.
Uranus is just past opposition. The distant planet becomes reachable by telescope after around 6:24pm once skies darken and Uranus rises above the thick atmosphere near the horizon. It is currently in the constellation Taurus, shining at magnitude 5.6.
Neptune is visible in the southeast sky once skies are dark. Neptune sets low enough to preclude telescopic examination around 11:45pm as it sinks into the thick atmosphere near the horizon It is currently shining at magnitude 7.8 in the constellation Pisces.