[Take the December 2024 Quiz – Christmas Special]
So what’s on this month?

A monthly look at astronomical events in the sky and on Earth
Compiled by Steve Sawyer
Welcome to December’s “What’s Up”!
Well first I can’t believe the year has passed so quickly. I just looked back at last December’s What’s Up and it seemed like 5 minutes since I wrote it!
I hope everyone has had a fantastic year filled with the excitement and wonder of exploring astronomy!
This month we can look forward to Dave’s Christmas lecture on the 6th December 2024 (don’t miss it).

Our other events coming up are :-
Date | Title | Speaker |
---|---|---|
20/12/2024 | Festive Meal, Observing and Quiz Evening | York AS Members |
03/01/2025 | Member’s Evening – Short Talks | York AS Members |
17/01/2025 | Early German Rocket Development | Martin Dawson |
07/02/2025 | Astronomy of the Islamic Calendar | Qamar Uddin |
For further details see the events page [Astronomy Presentations by guest speakers | York Astro](https://yorkastro.org.uk/astronomy-presentations/) and our Facebook group [(20+) The York Astronomical Society Chat Group | Facebook](https://www.facebook.com/groups/yorkastro) |
And in the night sky this month we can look forward to the annual Gemminid meteor shower, the winter solstice, followed by the Ursid meteor shower. Not forgetting the sight of Santa and his reindeer in the night sky on the 24!
But before all that….
The What’s Up! December 2024 Quiz
Take the Christmas quiz!, use the link and answer the questions as set by John Rowland. Good luck!
https://forms.gle/qhFV6YyrzGfBKNaZ7
So what’s on this month?
Ursa Major is now climbing in the east, with its fainter southern stars fully visible, while Ursa Minor hangs below Polaris in the north. Nearby, the faint constellations Camelopardalis and Lynx are visible. In the northwest, Vega skims the horizon, with Deneb and parts of Cygnus still visible farther west. Rising in the east are Regulus and Leo, with Cancer, Gemini, and Perseus high overhead. The Milky Way is prominent, spanning from Cassiopeia in the west to Orion in the east. The Pleiades and Hyades clusters are southward, while Taurus, Auriga, Gemini, and Orion are well-positioned for observation, alongside Canis Major, Canis Minor, and Lepus. In the west, Aquarius has set, Cetus is lowering, and Pisces, Aries, Triangulum, and Andromeda remain visible. The Great Square of Pegasus appears as a diamond nearing the western horizon.
Sky Diary

Date | Event |
---|---|
December 1 | New Moon |
December 1 | Antares 0.1ºN of the Moon |
December 2 | Mercury (mag. 2.7) 5.0ºN of the Moon |
December 4-20 | Geminid meteor shower |
December 4 | Venus (mag. -4.2) 2.3ºN of the Moon |
December 7 | Jupiter at opposition (mag. -2.8) |
December 8 | Saturn (mag. 1.0) 0.3ºS of the Moon |
December 8 | First Quarter |
December 9 | Neptune (mag. 7.9) 0.8ºS of the Moon |
December 12 | Moon at perigee = 365,361 km |
December 13 | Uranus (mag. 5.6) 4.4ºS of the Moon |
December 14-15 | Geminid meteor shower maximum |
December 14 | Minor planet (15) Eunomia at opposition (mag. 8.0) |
December 14 | Aldebaran 10.3ºS of the Moon |
December 14 | Jupiter (mag. -2.8) 5.5ºS of the Moon |
December 15 | Full Moon |
December 17-26 | Ursid meteor shower |
December 17 | Pollux 2.1ºN of the Moon |
December 18 | Mars (mag. -0.9) 0.9ºS of the Moon |
December 20 | Regulus 2.4ºS of the Moon |
December 21 | Northern winter solstice |
December 22 | Last Quarter |
December 23 | Ursid meteor shower maximum |
December 24 | Moon at apogee = 404,485 km |
December 24 | Spica 0.2ºS of the Moon |
December 25 | Mercury at greatest elongation (22.0ºW, mag. -0.4) |
December 28 | Antares 0.1ºN of the Moon |
December 29 | Mercury (mag. -0.4) 6.4ºN of the Moon |
December 30 | New Moon |
This table captures the astronomical events for December, including phases of the moon, planetary alignments, and other notable occurrences.
Sky Maps
Looking South on the 15th at 22:00

Looking North on the 15th at 22:00

The two charts above show all DSOs of magnitude 6.0 or brighter. They are both taken from
SkyViewCafe.com and correct for the 15th of the month. For a clickable list of Messier objects with images, use the Wikipedia link.
Decembers Objects

The Sun

The above sunspot image isn’t quite current as the Stanford university servers that supply these images have been damaged by flooding. I hope they dry out soon.
No CME’s inbound at the time of writing. Use the resources linked below to keep abreast of any changes.
Resources
For more info on the sun and solar weather look here : –
Space Weather Enthusiasts Dashboard | NOAA / NWS Space Weather Prediction Center
Auroa Forecasts
A bit US centred but still useful
Aurora Dashboard (Experimental) | NOAA / NWS Space Weather Prediction Center
And our own Met-office have an excellent space weather forecast page here Space Weather – Met Office
The Moon

Decembers Lunar Calendar

Decembers moon calendar from Sky View Café (skyviewcafe.com)
A full yearly lunar calendar can be found here :-
The Moons Positions in December
Date | Event |
---|---|
December 1 | Moon is 0.1ºS of Antares in Scorpius |
December 2 | Moon is 5.0ºS of Mercury (too close to the Sun to be visible) |
December 4 | Moon is 2.3ºS of Venus (mag. -4.2) in Sagittarius |
December 8 | Moon is 0.3ºN of Saturn in Aquarius |
December 9 | Moon passes 0.8ºN of Neptune |
December 13 | Moon is 4.4ºN of Uranus |
December 14 | Moon is 10.3ºN of Aldebaran and later 5.5ºN of Jupiter (mag. -2.8) |
December 17 | Moon is 2.1ºS of Pollux |
December 18 | Moon is 0.9ºN of Mars, which has begun to retrograde in Cancer |
December 20 | Moon passes 2.4ºN of Regulus |
December 24 | Moon is 0.2ºN of Spica |
December 28 | Moon is 0.1ºS of Antares |
December 29 | Moon is 6.4ºS of Mercury, one day before New |
Moon Feature
Crater Gassendi
- Location: At the northern edge of Mare Humorum.
Gassendi is a prominent lunar impact crater located at the northern edge of Mare Humorum, named after the French astronomer Pierre Gassendi. This crater was partially filled with lava during the mare’s formation, leaving only its rim and central peaks visible above the surface. Its outer rim, though worn and eroded, retains a circular shape. A smaller crater, Gassendi A, intrudes into its northern rim and connects to a rugged uplift in the northwest portion of the crater floor, together resembling a diamond ring.
The southern floor of Gassendi features a semi-circular ridge that mirrors the outer rim’s shape. The rim dips to its lowest point in the south, creating a noticeable gap. Rim heights vary from 200 meters to 2.5 kilometers. The crater floor is dotted with hummocks, rough areas, and intersecting rilles known as the Rimae Gassendi.
Gassendi A, located just north of Gassendi, has a distinctive ray system and is classified as part of the Copernican System. Historically, it was referred to as Clarkson on some older maps after British amateur astronomer Roland L. T. Clarkson, but this name is not officially recognized.
Gassendi was once considered as a potential Apollo landing site and was extensively imaged by Lunar Orbiter 5 for evaluation. It was also photographed in detail during the Apollo 16
The craters unique “starburst” pattern of ridges and rilles can evoke the appearance of a snowflake or diamond ring under favourable lighting, particularly near the first or last quarter Moon. This makes the crater an ideal feature for our December issue.

A nice flyover can he found here Gassendi Crater Flyover – NASA Science
And some close up images from LROC Gassendi’s Fractures | Lunar Reconnaissance Orbiter Camera
Planets

Mercury
Mercury starts December poorly placed in the evening sky but transitions to the morning sky after its inferior conjunction on the 6th, where it remains for the rest of the month. The best opportunity to observe it comes after mid-month. On the 15th, it shines at magnitude +0.6 and rises 100 minutes before sunrise. By the 23rd, at its greatest western elongation, it brightens to magnitude -0.2 and rises nearly two hours before the Sun.
Venus
Venus, at magnitude -4.0, is well-positioned in the evening sky after sunset. A 12%-lit waxing crescent Moon is located 4.8° southwest of Venus on the 4th, and at 19% illumination, it appears 8.5° east-southeast on the 5th. By December 31, as Venus nears its greatest eastern elongation on January 10, 2025, it brightens to magnitude -4.2 and sets 4 hours and 15 minutes after sunset.
Mars
Mars reaches opposition next month. On December 1, it shines at magnitude -0.5, sits 2° from the Beehive Cluster, and displays an 11-arcsecond disc. On the 6th, it reverses its eastward motion and begins moving westward relative to the background stars. The Moon will occult Mars (mag. -0.9) on the 18th during daylight (see page 46). By the end of December, Mars brightens to magnitude -1.2 and reveals a 14-arcsecond disc through a telescope
Jupiter
Jupiter shines brightly in December, reaching opposition on the 7th at magnitude -2.7 and remaining visible all night near the Hyades in Taurus. This is a great time to observe a full rotation of Jupiter, which takes just under 10 hours. On December 8, Ganymede and its shadow transit Jupiter’s disc, an event rare to see aligned with opposition. On December 14, the Full Moon joins Jupiter, separated by just 4.6°. By December 31, Jupiter sits 5.8° northeast of Aldebaran, with the Hyades and Pleiades clusters nearby. It reaches its peak altitude of 60° all month under dark skies.
Saturn
Saturn reaches its highest position on December 1 but begins drifting west of south and losing altitude after the 10th. By month’s end, it sits 26° above the south-southwest horizon at nightfall, with Venus approaching for a close encounter on January 18, 2025.
Uranus
At magnitude +5.6, Uranus reaches its highest point in the sky during dark evenings all month, positioned southwest of the Pleiades.
Neptune
Neptune, at magnitude +7.9, reaches its peak altitude of 35° under dark skies throughout the month. It is located south-southwest of the Circlet asterism in Pisces.
Meteor Showers

The Geminids
The Geminid meteor shower will be active from December 4 to December 17, peaking around December 14. During this time, Geminid meteors can be observed whenever the radiant point in the constellation Gemini is above the horizon.
From York, the radiant remains above the horizon all night, making the shower visible throughout the hours of darkness. The best displays are expected around 02:00 GMT, when the radiant is highest in the sky, aligning York optimally to face the incoming meteors. At this time, meteors will appear to rain straight down, producing short, bright trails. At other times, meteors may enter the atmosphere at oblique angles, creating longer, slower trails across the sky.
The shower’s peak activity is anticipated around 02:00 GMT on December 14, with a nominal zenithal hourly rate (ZHR) of 120 meteors per hour under ideal conditions. From York, with the radiant reaching a maximum altitude of 69°, observers could see up to 112 meteors per hour at the peak. However, the nearly full Moon in Taurus will cause significant light interference, reducing visibility throughout the night.

Diagrams from https://in-the-sky.org/ (c) Dominic Ford
Comets
Comet | Mag |
---|---|
C/2023 A3 (Tsuchinshan-ATLAS) | 8 |
333P/LINEAR | 9 |
C/2022 E2 (ATLAS) | 11 |
C/2024 S1 (ATLAS) | 12 |
C/2023 C2 (ATLAS) | 13 |
C/2024 M1 (ATLAS) | 13 |
13P/Olbers | 13 |
29P/Schwassmann-Wachmann 1 | 13 |
Link here for further details of each comet and how to locate it.
Visual Comets in the Future (Northern Hemisphere) (aerith.net)
Deep Sky (DSO’s)

Christmas Tree Cluster (NGC 2264)
- Type: Open Cluster
- Location: Constellation Monoceros (near Orion)
- Details: This cluster resembles a Christmas tree, with its “trunk” pointing toward the bright star S Monocerotis. It is part of a larger region that includes the Cone Nebula and the Fox Fur Nebula.
Hind’s Crimson Star (R Leporis)
- Type: Variable Carbon Star
- Location: Constellation Lepus (below Orion)
- Details: A striking red star that becomes vibrant during its variability cycle, appearing like a “Christmas ornament” in the sky.
The Little Dumbbell Nebula (M76)
- Type: Planetary Nebula
- Location: Constellation Perseus
- Details: Resembling a smaller version of the Dumbbell Nebula (M27), this planetary nebula is dimmer but offers an interesting challenge for astrophotographers and observers alike.
The Flaming Star Nebula (IC 405)
- Type: Reflection/Emission Nebula
- Location: Constellation Auriga
- Details: A fiery, wispy nebula illuminated by the nearby star AE Aurigae. It’s faint but photogenic, glowing with reds and blues that resemble a cosmic flame.
Thor’s Helmet (NGC 2359)
- Type: Emission Nebula
- Location: Constellation Canis Major
- – Details: This nebula resembles the winged helmet of Thor from Norse mythology. It’s powered by a massive Wolf-Rayet star
ISS and other orbiting bits
Date | Visible | Max Height | Appears | Disappears |
---|---|---|---|---|
Wed Nov 27, 5:31 PM | 6 min | 49° | 10° above W | 18° above ESE |
Wed Nov 27, 7:08 PM | 1 min | 18° | 10° above W | 18° above WSW |
Thu Nov 28, 4:43 PM | 7 min | 55° | 10° above W | 10° above ESE |
Thu Nov 28, 6:19 PM | 4 min | 27° | 10° above W | 24° above S |
Fri Nov 29, 5:31 PM | 6 min | 34° | 10° above W | 11° above SE |
Fri Nov 29, 7:09 PM | 1 min | 11° | 10° above WSW | 11° above SW |
Sat Nov 30, 4:42 PM | 6 min | 43° | 10° above W | 10° above SE |
Sat Nov 30, 6:20 PM | 4 min | 16° | 10° above WSW | 10° above S |
Sun Dec 1, 5:31 PM | 5 min | 21° | 10° above W | 10° above SSE |
Mon Dec 2, 4:42 PM | 6 min | 28° | 10° above W | 10° above SE |
Tue Dec 3, 5:32 PM | 3 min | 12° | 10° above WSW | 10° above SSW |
Wed Dec 4, 4:42 PM | 4 min | 16° | 10° above WSW | 10° above S |
Use the this NASA website for exact timings for York overpasses. York, England, United Kingdom | Sighting Opportunity | Spot The Station | NASA
Useful Resources
StarLust – A Website for People with a Passion for Astronomy, Stargazing, and Space Exploration.
http://www.n3kl.org/sun/noaa.html
http://skymaps.com/downloads.html
Astronomy Calendar of Celestial Events 2024 – Sea and Sky (seasky.org)
https://www.constellation-guide.com
IMO | International Meteor Organization
and of course the Sky at Night magazine!
Astronomy and Space Quiz
Compiled by John Rowland This Month’s Quiz – Christmas 2024 Special 12 multi-choice questions for beginners up to experts level. Please click on the link below to take the quiz. Follow the December 2024 Quiz link here! And Good Luck!
The winner(s) will be posted on the website (“Leave a Reply”) and also at the next YAS Meeting after the 15th.
All very good stuff Steve. Thanks again, MW2