by Mark Phillips
You see the video of Jim Nisbet’s guide to the Sky in December 2024 from our 6 December meeting.
The charts show the sky at 21:00 GMT 15 December 2024.
Highlights:
- Jupiter is still the brightest and easiest to observe planet on display, visible all night long and at opposition on 7 December. Saturn also still visible low down in the south with rings closing up. Mars rising later on but small size telescopically. Venus bright but low in the South at dusk.
- Comet C/2023 A3 (Tsuchinshan-ATLAS) still on display but rapidly fading.
- The Geminids meteor shower peaks on 14 December. Rates may peak at over 100 per hour but the waxing almost full moon will interfere.
- New Moon 1 Dec, Full Moon 15 Dec
- Winter solstice: Sat 21 Dec 2024 at 09:20 GMT
- Although there are a number of planetary occultations by the Moon this month, none are easily visible from Edinburgh.
Click on an item to expand for more information:
For 15 Dec 2024 from in-the-sky.org
Mercury recently passed behind the Sun at superior solar conjunction. From Edinburgh, it is not observable – it will reach its highest point in the sky during daytime and is 2° below the horizon at dusk.
07 Sep 2024 – Mercury at highest altitude in morning sky
16 Nov 2024 – Mercury at greatest elongation east
24 Nov 2024 – Mercury at highest altitude in evening sky
20 Dec 2024 – Mercury at highest altitude in morning sky
Venus is emerging into the evening sky as it approaches greatest elongation east. From Edinburgh, it will become visible at around 16:06 (GMT), 13° above your southern horizon, as dusk fades to darkness. It will then sink towards the horizon, setting 3 hours and 35 minutes after the Sun at 19:12.
24 Oct 2023 – Venus at greatest elongation west
10 Jan 2025 – Venus at greatest elongation east
10 Feb 2025 – Venus at highest altitude in evening sky
31 May 2025 – Venus at greatest elongation west
Mars is currently visible as a morning object. From Edinburgh, it is visible in the morning sky, becoming accessible around 22:26, when it reaches an altitude of 9° above your north-eastern horizon. It will then reach its highest point in the sky at 05:25, 55° above your southern horizon. It will be lost to dawn twilight around 06:43, 52° above your south-western horizon.
12 Jan 2023 – Mars ends retrograde motion
06 Dec 2024 – Mars enters retrograde motion
12 Jan 2025 – Mars at perigee
16 Jan 2025 – Mars at opposition
Jupiter is currently approaching opposition and is visible as a morning object. From Edinburgh, it is visible in the morning sky, becoming accessible around 19:14, when it reaches an altitude of 7° above your north-eastern horizon. It will then reach its highest point in the sky at 02:33, 56° above your southern horizon. It will be lost to dawn twilight around 06:59, 31° above your western horizon.
09 Oct 2024 – Jupiter enters retrograde motion
07 Dec 2024 – Jupiter at opposition
04 Feb 2025 – Jupiter ends retrograde motion
11 Nov 2025 – Jupiter enters retrograde motion
Saturn is currently an early evening object. From Edinburgh, it is visible in the evening sky, becoming accessible around 17:14 (GMT), 15° above your south-eastern horizon, as dusk fades to darkness. It will then reach its highest point in the sky at 20:13, 25° above your southern horizon. It will continue to be observable until around 23:50, when it sinks below 11° above your south-western horizon.
08 Sep 2024 – Saturn at opposition
15 Nov 2024 – Saturn ends retrograde motion
23 Mar 2025 – Saturn ring plane crossing
06 May 2025 – Equinox on Saturn
Data from in-the-sky.org
| Comet name | Mag | Constellation | Separation from Sun | Trend | Absolute magnitude last updated |
| C/2023 A3 (Tsuchinshan-ATLAS) | 8.9 | Aquila | 49° | Fading | 5 Sep 2024 |
| 333P/LINEAR | 11.3 | Ursa Major | 78° | Brightening | 2 Jun 2016 |
| C/2024 G3 (ATLAS) | 11.9 | Lupus | 21° | Brightening | 2 Aug 2024 |
| C/2024 S1 (ATLAS) | 12.7 | Hydra | 61° | Fading | 3 Oct 2024 |
| C/2022 E2 (ATLAS) | 12.8 | Camelopardalis | 131° | Brightening | 3 Oct 2024 |
| 37P/Forbes | 12.8 | Sagittarius | 43° | Fading | 2 Oct 2018 |
| 12P/Pons-Brooks | 12.9 | Lupus | 27° | Fading – in outburst | 3 Oct 2024 |
| 13P/Olbers | 13.5 | Ophiuchus | 12° | Fading | 3 Oct 2024 |
| 154P/Brewington | 13.6 | Leo | 104° | Fading | 8 Feb 2017 |
| 48P/Johnson | 14.2 | Sagittarius | 31° | Brightening | 31 Oct 2018 |
| C/2017 K2 (PANSTARRS) | 14.2 | Orion | 150° | Fading | 2 Dec 2023 |
| C/2023 C2 (ATLAS) | 14.3 | Sagittarius | 42° | Fading | 5 Sep 2024 |
| C/2021 G2 (ATLAS) | 14.3 | Libra | 22° | Brightening | 4 Apr 2024 |
| C/2021 S3 (PANSTARRS) | 14.4 | Cygnus | 84° | Fading | 1 May 2024 |
| 65P/Gunn | 15.4 | Libra | 7° | Brightening | 1 Aug 2017 |
| 21P/Giacobini-Zinner | 15.5 | Ophiuchus | 26° | Brightening | 4 Feb 2019 |
| 32P/ComasSola | 15.5 | Virgo | 44° | Fading | 14 Sep 2017 |
| C/2020 V2 (ZTF) | 15.8 | Pavo | 63° | Fading | 30 Aug 2023 |
| 60P/Tsuchinshan | 15.8 | Pisces | 129° | Brightening | 3 Oct 2020 |
| C/2020 K1 (PANSTARRS) | 16.1 | Columba | 108° | Fading | 30 Aug 2023 |
| 43P/Wolf-Harrington | 16.2 | Pisces | 147° | Brightening | 4 Dec 2018 |
| 47P/Ashbrook-Jackson | 16.3 | Sagittarius | 33° | Brightening | 29 Feb 2012 |
| C/2022 L2 (ATLAS) | 16.4 | Vela | 83° | Brightening | 1 May 2024 |
| C/2019 U5 (PANSTARRS) | 16.5 | Puppis | 97° | Fading | 3 Jul 2023 |
| 69P/Taylor | 16.5 | Sagittarius | 58° | Fading | Unknown |
The position of each comet is calculated from orbital elements published by the Minor Planet Center (MPC).
The Geminid meteor shower will be active from 4 December to 17 December, producing its peak rate of meteors around 14 December.
Over this period, there will be a chance of seeing Geminid meteors whenever the shower’s radiant point – in the constellation Gemini – is above the horizon.
From Edinburgh , the radiant point is above the horizon all night, which means that the shower will be active throughout the hours of darkness.
The shower is likely produce its best displays in the hours around 02:00 GMT, when its radiant point is highest in the sky.
The shower is expected to reach peak activity at around 02:00 GMT on 14 December 2024.
At its peak, the shower is expected to produce a nominal rate of around 120 meteors per hour (ZHR). However, this zenithal hourly rate is calculated assuming a perfectly dark sky and that the radiant of the shower is situated directly overhead. In practice, any real observing sight will fall short of these ideal conditions. The number of meteors you are likely to see is thus lower than this, and can be estimated using the ZHR formula.
From Edinburgh, the radiant of the shower will appear at a peak altitude of 67° above your horizon, and on the basis of this, we estimate that you may be able to see up to 110 meteors per hour at the shower’s peak.
The Moon, in Taurus, will be only one day away from full phase at the shower’s peak, presenting significant interference throughout the night.
The parent body responsible for creating the Geminid shower has been identified as asteroid 3200 Phaethon.
21 December will be the shortest day of 2024 in the northern hemisphere, midwinter day.
Sat 21 Dec 2024 at 09:20 GMT
This is the day when the Sun’s annual journey through the constellations of the zodiac reaches its most southerly point in the sky, in the constellation of Capricornus at a declination of 23.5°S. This day is counted by astronomers to be the first day of winter in the northern hemisphere.
In the southern hemisphere, the Sun is above the horizon for longer than on any other day of the year, and astronomers define this to be the first day of summer.
At the solstice, the Sun appears overhead at noon when observed from locations on the tropic of Capricorn, at a latitude 23.5°S.
| Stars | Open Clusters | Globular Clusters | Galaxies |
| Aldebaran (mag 1.0) | Caldwell 41 (mag 1.0) | NGC 1587 (mag 11.7) | |
| Elnath (mag 1.7) | Messier 45 (mag 1.3) | NGC 1589 (mag 11.8) | |
| Alcyone (mag 2.9) | NGC 1746 (mag 6.1) | NGC 1615 (mag 12.0) | |
| ζ-Tau (mag 3.0) | NGC 1647 (mag 6.4) | NGC 1550 (mag 12.1) | |
| θ²-Tau (mag 3.4) | NGC 1807 (mag 7.0) | NGC 1642 (mag 12.6) | |
| λ-Tau (mag 3.4) | NGC 1817 (mag 7.7) | NGC 1349 (mag 13.1) | |
| Ain (mag 3.5) | NGC 1750 | NGC 1541 (mag 13.5) | |
| Atlas (mag 3.6) | NGC 1758 | NGC 1590 (mag 13.7) | |
| O-Tau (mag 3.6) | NGC 1802 | NGC 1474 (mag 13.8) | |
| γ-Tau (mag 3.6) | NGC 1996 | NGC 1542 (mag 13.9) | |
| Electra (mag 3.7) | NGC 2026 | NGC 1588 (mag 14.1) | |
| ξ-Tau (mag 3.7) | NGC 1517 (mag 14.2) | ||
| δ-Tau (mag 3.8) | NGC 1633 (mag 14.5) | ||
| θ¹-Tau (mag 3.8) | IC 1977 (mag 14.6) | ||
| Maia (mag 3.9) | NGC 1497 (mag 14.6) | ||
| ν-Tau (mag 3.9) | IC 357 (mag 14.6) | ||
| f-Tau (mag 4.1) | NGC 1593 (mag 14.7) | ||
| Merope (mag 4.2) | NGC 1409 (mag 14.8) | ||
| κ-Tau (mag 4.2) | IC 331 (mag 14.8) | ||
| τ-Tau (mag 4.3) | IC 365 (mag 14.8) | ||
| d-Tau (mag 4.3) | IC 338 (mag 14.9) | ||
| V776 Tau (mag 4.3) | IC 1967 (mag 14.9) | ||
| c¹-Tau (mag 4.3) | NGC 1634 (mag 15.0) | ||
| μ-Tau (mag 4.3) | IC 330 (mag 15.0) | ||
| υ-Tau (mag 4.3) | IC 329 (mag 15.1) | ||
| Taygeta (mag 4.3) | IC 2057 (mag 15.2) | ||
| 10-Tau (mag 4.3) | IC 363 (mag 15.2) | ||
| A¹-Tau (mag 4.4) | IC 358 (mag 15.2) | ||
| CE Tau (mag 4.4) | NGC 1410 (mag 15.2) | ||
| V777 Tau (mag 4.5) | NGC 1508 (mag 15.2) |
From our Newsletter:
Two comets for the small hours
by Douglas Heggie
According to the BAA, comet 29P/Schwassmann-Wachmann continues its current period of high activity. This does two things: it brightens the total magnitude (now around 12, according to COBS), and it gives interesting structure in the coma, which changes nightly as the most recent outbursts expand within the bright cloud remaining from outbursts earlier this month. The comet is close to Regulus and rises before midnight.
While you’re up, you might like to take a look at another comet in the vicinity, just above the rump of Leo. This is 333P/LINEAR, which is currently about magnitude 13, with a short tail. But it is brightening rapidly, and on Seiichi Yoshida’s excellent web page it is predicted to reach magnitude 10 before the year’s end. In the same period it rises rapidly through the handle of the Plough, along Draco and past Ursa Minor into Cepheus, and so soon you won’t even have to get up in the small hours to see it.
Use the chevrons to choose the month:
Much of the material is provided with thanks to Dominic Ford on his excellent site in-the-sky.org. Star charts by Cartes du Ciel.