Do you like standing outside during cold and dark December nights? Probably not. Stargazing at this time of year is never easy, though for anyone in the northern hemisphere now the cusp of winter it’s arguably the very best time of year to do just that.
The nights are long and dark, and allow bite-size stargazing sessions before supper. On December 21 we’ll celebrate the winter solstice in the northern hemisphere, the longest night of the year and the beginning of astronomical winter. That has obvious advantages to anyone looking at the night sky.
However, on that very same date is a special planetary event as Jupiter and Saturn get within 0.06° of each other in a super rare “Great Solstice Conjunction.” That’s not happened since the year 1623, and it hasn’t been this easy to see since the year 1226.
Now that is rare!
As well as a special solstice this month, will see a rare total solar eclipse in South America—minus international eclipse-chasers—as well as the year’s most powerful meteor shower. And that’s just the top-line highlights!
Here’s exactly what you need to know about when, where and how to catch December 2020’s stargazing highlights:
1. A ‘Great Solstice Conjunction’
When: Monday, December 21, 2020
Where to look: southwest immediately after sunset
Planets occasionally pass each other in the night sky, but rarely this close. Faster-moving Jupiter laps Saturn every 20 years, but not since 1623 has there been a “great conjunction” or “appulse” this close.
Even more impressively, not since 1226 has such a sight been this easily observable. To see the two planets just 0.06º apart have a look to the southwest immediately after sunset. Don’t waste any time—they’ll be sinking towards the horizon.
Why does it happen on the exact date of the solstice? That’s essentially a celestial coincidence, though an inevitable one given the long-term celestial mechanics at play.
2. A total solar eclipse
When: Monday, December 14, 2020
Where: “path of totality” through southern Chile and Argentina
A total solar eclipse doesn’t come along very long, so when travel is so affected by COVID-19 it’s a huge shame for international eclipse-chasers. During this uniquely South American event the Moon’s shadow will slip across Chile and Argentina in sweep across South America in 24 spell-binding minutes, plunging those near the center of the “path of totality” below into darkness for 2 minutes 9 seconds.
Those in Pucón, Chile and south of Neuquén in Patagonia, Argentina will experience a host of natural phenomena, from “crescent Sun” shadows on the ground and silvery light to dropping temperatures and a glorious glimpse of the Sun’s mighty white corona.
3. Geminid meteor shower
When: after dark through the early hours of the following morning, Sunday/Monday, December 13/14, 2020
Where to look: all-sky
The years most powerful meteor shower doesn’t get the attention it deserves. Despite it producing up to 150 multicoloured “shooting stars” per hour (if you’re in a dark sky site) in a display that begins well before midnight and lingers all night, it often gets ruined by cold, by cloud and by a bright Moon bleaching the sky.
At least the last factor won’t come into play this year, with the peak of this year’s Geminid meteor shower coinciding with a New Moon.
Those in the “path of totality” in South America may be able to glimpse some “shooting stars” in the northern sky just a few hours before witnessing a total solar eclipse … and perhaps even during totality itself. Wow!
4. Moon eclipses Venus
When: Saturday, December 12, 2020
Where to look: east before sunrise/eclipse during daylight in the morning
For most of us this event will be little more than a beautiful pairing of a super-slender Crescent Moon—just a few days before New Moon—and the super-bright planet Venus.
However, for those in western U.S. states the Moon will actually block Venus, though it takes place in daylight so only those with telescopes will be able to witness the event.
5. Crescent Moon, Jupiter and Saturn
When: Wednesday, December 16, 2020
Where to look: southwest after sunset
In something of a warm-up event for the “Great Solstice Conjunction” on December 21 comes the gorgeous sight of a two-day old Crescent Moon just 5º underneath Jupiter and Saturn, which themselves will be super-close—and be shining almost as one.
6. The Moon and Mars
When: Wednesday, December 23, 2020
Where to look: south after dark
However, before it recedes from us there’s just time for us to view the red planet about 5º from a big, bright Half-Moon a few days past its Last Quarter phase.
7. Full Cold Moon
When: Wednesday, December 30, 2020
Where to look: east at sunset, west at sunrise
Also called the “Long Nights Moon” for obvious reasons, the final Full Moon of the year appears a week after the solstice, so is the first Full Moon of the new season.
Here’s what the Moon is up to this month:
- Tuesday, December 8, 2020: Last Quarter Moon (Half-Moon)
- Monday, December 14, 2020: New Moon (causing a total solar eclipse, see above)
- Monday, December 21, 2020: First Quarter Moon (Half-Moon)
- Wednesday, December 30, 2020: Full Moon
Wishing you clear skies and wide eyes.