The barred spiral galaxy Andromeda is the nearest major galaxy to the Milky Way. It is catalogued as Messier 31 (M31) and is about 2.5 million light-years from Earth. Photo: MPAS member David Rolfe
Highlights this month
- 5TueMercury at greatest evening elongation (21° from the Sun, mag −0.4) — best evening apparition. (1:22am)
- 7ThuNeptune is stationary — resumes direct (eastward) motion. (6:07am)
- 13WedMercury is stationary — begins retrograde (westward) motion. (3:44pm)
- 14ThuGeminids meteor shower peaks (up to 150/hr). A thin 2% Moon leaves the sky dark.
- 18MonThe Moon passes Saturn — 2° apart. (10:45am)
- 22FriSummer solstice.
- 22FriUrsids meteor shower peaks (up to 10/hr). A bright 76% Moon interferes badly this year.
- 22FriThe Moon passes Jupiter — 2° apart. (11:39pm)
- 23SatMercury in inferior conjunction with the Sun — lost in the glare. (5:48am)
During December, the constellations Taurus, Gemini, Orion and Auriga are visible. Looking towards the north you can see the distinct upside-down ‘V’ shape of the Hyades open star cluster, which marks the head of the constellation Taurus. Within Taurus you can also observe the open star cluster Pleiades, or M45, which can be seen with the naked eye and is a wonderful sight through a small telescope. Just next to it towards the northeast is Orion, a magnificent sight with its bright stars Rigel and Betelgeuse and the fantastic nebula M42.
Emerging from the foot of Orion, Eridanus meanders high across the sky. Look out for Perseus and Auriga below Taurus in the north. Auriga can be found by locating the bright star Capella, which is low in the sky this month.
December is also a great time to look out for the Magellanic Clouds, which can be seen sitting in the southern part of the night sky. The Small Magellanic Cloud (SMC) sits in Tucana, while the Large Magellanic Cloud (LMC) hovers on the border of the constellations Dorado and Mensa. Look out for the Tarantula Nebula (NGC 2070) in the LMC.
On the night of December 14-15 we have the Geminids meteor shower, which is considered to be one of the most spectacular meteor showers of the year. The shower owes its name to the constellation Gemini because the meteors seem to emerge from this constellation. Unlike most other meteor showers, the Geminids are not associated with a comet but with an asteroid called 3200 Phaethon. As Earth passes through a massive trail of dusty debris shed by the weird, rocky object, the dust and grit burn up as it runs into Earth’s atmosphere in a flurry of shooting stars. The asteroid takes about 1.4 years to orbit the sun.
This month’s conjunctions, which is when two astronomical objects appear close to each other in the sky, include the moon and Venus on December 10, the moon and Saturn on December 18, and then the moon and Jupiter on December 23.
By Nerida Langcake
This article appeared in the December 2023 issue of the Mornington Peninsula Magazine.
The sky in detail — December 2023
Sun & twilight
| Date | Sunrise | Sunset | Day length | Astro. dark begins | ends |
|---|---|---|---|---|---|
| Fri 1 | 5:51am | 8:27pm | 14h 36m | 10:19pm | 3:59am |
| Sun 10 | 5:50am | 8:35pm | 14h 45m | 10:30pm | 3:55am |
| Wed 20 | 5:52am | 8:42pm | 14h 50m | 10:39pm | 3:55am |
| Sun 31 | 5:59am | 8:46pm | 14h 47m | 10:42pm | 4:03am |
Days lengthen by about 11 minutes over the month.
The Moon
- Last QuarterTue 5, 4:48pm
- New MoonWed 13, 10:37am
- First QuarterWed 20, 5:41am
- Full MoonWed 27, 11:34am
Apogee 5 Dec (404,800 km) · Perigee 17 Dec (367,700 km)
The planets
Rise/set for mid-month at The Briars.
| Planet | In | Mag | Rise | Transit | Set | Best |
|---|---|---|---|---|---|---|
| Mercury | Sgr | 0.8 | 6:59am | 2:21pm | 9:43pm | Hidden |
| Venus | Lib | −4.0 | 3:42am | 10:28am | 5:14pm | Hidden |
| Mars | Oph | 1.4 | 5:19am | 12:40pm | 8:01pm | Hidden |
| Jupiter | Ari | −2.5 | 4:39pm | 10:01pm | 3:27am | Evening |
| Saturn | Aqr | 0.8 | 11:22am | 6:03pm | 12:49am | Evening |
| Uranus | Ari | 5.7 | 5:49pm | 10:54pm | 4:03am | Evening |
| Neptune | Psc | 7.9 | 1:16pm | 7:28pm | 1:44am | Evening |
Meteor showers
- Geminids — peaks 14 December, radiant in Gemini (up to 150/hr). The richest shower of the year; the radiant reaches a useful altitude after local midnight, so it rewards southern observers well. A thin 2% Moon leaves the sky dark.
- Ursids — peaks 22 December, radiant in Ursa Minor (up to 10/hr). A circumpolar northern shower whose radiant never rises from Victoria. A bright 76% Moon interferes badly this year.
Computed for The Briars, Mt Martha. Times are local (Melbourne).
Generated automatically from the MPAS sky engine on 15 July 2026.
The solar system — December 2023
Evening sky Morning sky Up much of the night Lost in the Sun’s glare
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