What’s Up in Denver? December 15th through 21st, 2025

Here’s a brief look at what’s going on in the Mile High City this week.

December 15:

Look for the Andromeda Galaxy (M31) at Zenith: In dark skies, this galaxy can be spotted with the naked eye. It’s a great target for binocular viewing especially when directly overhead: 7:05 PM
Catch the waning Geminids meteor shower – even though it peaked on the evening of December 13/14, the Geminids should still put on a show of up to 50 meteors per hour under dark clear skies after midnight.

December 16:

Catch the waning crescent Cold Moon near Zubenelgenubi: Zubenelgenubi is a multiple star system in the constellation Libra (The Scales), named from Arabic for the “southern claw” of the Scorpion, and it’s a white sub-giant visible to the naked eye, known for being a visual double star where each component is itself a spectroscopic binary, making it at least four stars: Find it in the early morning eastern skies around 5:00 AM

December 17:

OH MY! Revealing the Solar System with JWST

Space Telescope Science Institute: Planets, Asteroids, and Interstellar Interlopers, OH MY! Revealing the Solar System with JWST with Dr. Stefanie Milam of NASA (Free virtual program): Livestream on Youtube: 2:00 PM
DAS Astrophotography Special Interest Group (ASIG) – Advanced Image Processing (Virtual program – check membership email and Slack for details): Online via Zoom: 7:00 PM
The waning crescent Cold Moon reaches Apogee (it’s farthest point in it’s orbit around the Earth at 406,324 km): 06:09 UTC

December 18:

Amateur Astronomers Association: Tour of the Winter Sky 2025

Amateur Astronomers Association: Tour of the Winter Sky 2025 (Free virtual program – registration required): Online via Zoom: 5:00 PM
Standley Lake Stargazing: Year In Review – Astronomy and Spaceflight (Free virtual program): Online via Zoom: 6:00PM
Catch the last of the waning crescent Cold Moon close to Mercury and Antares – the bright red star in the constellation Scorpius low in the eastern sky just before sunrise.

December 19 (Dark Sky Weekend):

Catch the Summer Triangle before it disappears. The Summer Triangle is an asterism of stars made up of Vega in Lyra, Altair in Aquila, and Deneb in Cygnus. Now is a great time to catch it in the early evening before it sinks into the west and disappears from view until next summer when it will return in the east. Find it low in the western skies right after sunset: 6:30 PM
New Wolf Moon in the constellation Sagittarius: 6:43 PM

December 20 (Dark Sky Weekend):

Milky Way at the Kline-Dodge Dark Site by DAS member Jerry Osborn.

DAS Scheduled Kline-Dodge Dark Sky Site Orientation: Check Slack and the DAS Membership portal for details; 4:00 PM

December 21 (Dark Sky Weekend):

Winter Solstice: due to Earth’s axial tilt, the winter solstice marks the furthest point from the Sun and the start of astronomical winter with the longest night of the year. Paired with the new moon, it is perfect night for stargazing. 8:03 AM

This Week’s Meteoric Activity:

You can keep track of the activity of meteor showers as well as those beyond the limits of visual observing by visiting the NASA Meteor Shower Portal.

Geminids (GEM): 2:00 AM in northern Gemini — Up to 50 per hour (rapidly decreasing after peak)
Anthelion (ANT): 1:00 AM in western Gemini — 3 per hour
Monocerotids (MON): 2:00 AM in northern Monoceros — 2 per hour
σ Hydrids (HYD): 3:00 AM in western Hydra — 2 per hour
Southern χ Orionids (ORS): Midnight in northeastern Orion — Less than 1 per hour
η Hydrids (EHY): 4:00 AM in western Hydra — Less than 1 per hour
Comae Berenicids (COM): 5:00 AM in eastern Leo Minor — Less than 1 per hour
December χ Virginids (XVI): Last hour before dawn in southwestern Virgo — Less than 1 per hour
Ursids (URS): Pre-dawn hours in eastern Camelopardalis — Less than 1 per hour
December σ Virginids (DSV): Last hour before dawn in northern Virgo — Less than 1 per hour
December α Bootids (DAB): Last hour before dawn in southern Boötes — Less than 1 per hour
κ Velids (KVE): 3:00 AM in western Vela — Less than 1 per hour