The Sky over the Mornington Peninsula — December 2121
Highlights this month
- 1MonThe Moon passes Jupiter — 5° apart. (4:41pm)
- 8MonVenus in superior conjunction with the Sun — lost in the glare. (3:43am)
- 14SunGeminids meteor shower peaks (up to 150/hr). A thin 19% Moon leaves the sky dark.
- 17WedMercury at greatest evening elongation (21° from the Sun, mag −0.5) — best evening apparition. (12:36am)
- 18ThuJupiter is stationary — begins retrograde (westward) motion. (9:13am)
- 22MonSummer solstice.
- 22MonUrsids meteor shower peaks (up to 10/hr). A bright 96% Moon interferes badly this year.
- 24WedMercury is stationary — begins retrograde (westward) motion. (9:22pm)
- 25ThuThe Moon passes Saturn — 0.5° apart. (12:10pm)
- 29MonThe Moon passes Jupiter — 5° apart. (1:47am)
Sun & twilight
| Date | Sunrise | Sunset | Day length | Astro. dark begins | ends |
|---|---|---|---|---|---|
| Mon 1 | 5:50am | 8:27pm | 14h 37m | 10:19pm | 3:58am |
| Wed 10 | 5:50am | 8:35pm | 14h 46m | 10:30pm | 3:55am |
| Sat 20 | 5:52am | 8:42pm | 14h 50m | 10:39pm | 3:55am |
| Wed 31 | 5:59am | 8:46pm | 14h 47m | 10:42pm | 4:03am |
Days lengthen by about 11 minutes over the month.
The Moon
- Last QuarterTue 2, 10:46am
- New MoonWed 10, 11:49am
- First QuarterWed 17, 3:08pm
- Full MoonWed 24, 12:10pm
Apogee 4 Dec (405,000 km) · Perigee 19 Dec (369,200 km)
The planets
Rise/set for mid-month at The Briars.
| Planet | In | Mag | Rise | Transit | Set | Best |
|---|---|---|---|---|---|---|
| Mercury | Sgr | −0.5 | 7:15am | 2:44pm | 10:13pm | Hidden |
| Venus | Oph | −3.8 | 5:58am | 1:22pm | 8:47pm | Hidden |
| Mars | Sgr | 1.3 | 7:03am | 2:28pm | 9:54pm | Hidden |
| Jupiter | Leo | −2.0 | 12:37am | 6:01am | 11:25am | Morning |
| Saturn | Gem | −0.4 | 10:04pm | 2:57am | 7:46am | Morning |
| Uranus | Gem | 5.5 | 10:39pm | 3:33am | 8:22am | Morning |
| Neptune | Vir | 8.0 | 3:18am | 9:57am | 4:36pm | Morning |
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 19% 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 96% Moon interferes badly this year.
The solar system — December 2121
Evening sky Morning sky Up much of the night Lost in the Sun’s glare
Open the full interactive orrery ↗ — fast-forward, pick any date, toggle the Moon and more.
Looking for an earlier month? Browse all past monthly guides →
Generated automatically from the MPAS sky engine on 9 September 2026.