After a wait of 397 years in orbit, we’re finally getting a truly ‘Great’ Conjunction.
Recently, December 21, 2020, Jupiter and Saturn finally met.
Looking towards the southwest skies from the northern hemisphere, an observer would see the sights in the sky shift as shown by viewing the heavens at the same time from November 30 to December 28, 2020: about 1 hour after sunset. Jupiter and Saturn make their closest approach on the night of December 21, 2020. (E. SIEGEL / STELLARIUM)
Passing within 0.1° of each other, this is the closest
Great Conjunction since 1623, and a sight unseen since 1226.
With the smallest angular separation in Earth’s skies since the year 1623, the December 21, 2020 great conjunction of Jupiter and Saturn will cause both planets to simultaneously be visible, along with their moons, in the eyepieces of most amateur and many professional telescopes. (E. SIEGEL / STELLARIUM)
Here are 7 must-follow tips.
To even the naked eye, Jupiter and Saturn will feature prominently in the southwestern skies shortly after sunset throughout the remainder of December. They will make a great sight in telescopes for another few days and an excellent pair in binoculars until December 30th or so. (NASA/BILL INGALLS)
1.) Look southwest ~30–45 minutes after sunset. Jupiter will be the “first star” visible post-sunset, appearing worldwide once the sky darkens.
Jupiter and Saturn have been approaching slowly over the past few months. Here, this December 20, 2020 photo shows the pair after sunset over the famous windmill in Brill, England. Although they get close every 20 years periodically in their orbit, this will be the first time they are this close and visible (not in the Sun’s glare) since the year 1226. (Jim Dyson/Getty Images)
2.) Look with your naked eye first. You’ll see Jupiter and Saturn separately if your vision is better than 20’/100’ (6m/30m), with bright Jupiter outshining Saturn by over 1000%.
On December 17, 2020, the crescent Moon passed close by the Jupiter/Saturn pair, as they approach conjunction on December 21. Alternately known as a ‘double planet,’ a ‘Christmas/Solstice star,’ or the ‘Great Conjunction,’ this sight is a delight for skywatchers with cooperative cloud cover all over the world. (Chris McGrath/Getty Images)
3.) Europe and Africa have the best views. The exact moment of closest approach is 18:37 Universal Time on December 21: just 8½ hours after solstice.
With either a small telescope or a good pair of (mounted) binoculars, Saturn’s rings, the distorted ‘ear-like’ shapes they create, and Jupiter’s bright disk and four brightest moons can all be easily revealed in the same field of view. Although they’ll appear best in telescopes on the night of December 21, 2020, they’ll be excellent in binoculars for as long as Jupiter and Saturn are visible. (ISAAC BONYUET OF INSTAGRAM AND TWITTER)
4.) What will I see? Binoculars or a 3” (8cm) telescope reveal up to four of Jupiter’s moons, with larger telescopes showcasing planetary bands, Saturn’s Titan, and ring features.
This image, taken just 1 day before the great conjunction, shows Jupiter and Saturn imaged together in the same telescope eyepiece. Careful examination reveals a much brighter Jupiter, a fainter, smaller Saturn whose rings are larger than Jupiter, and Jupiter’s bands with three moons and 1 faint background star. (CHRISTIAN FRÖSCHLIN/@CHRFRDE ON TWITTER)
5.) Marvel at Saturn’s rings! Saturn is 15% smaller than Jupiter and twice as distant, but its enormous rings cause Saturn to apparently exceed Jupiter’s diameter.
6.) Don’t let clouds discourage you. Watch virtually here, while the planets remain close until 2021’s arrival.
If your skies are cloudy, lots of people and observatories are set up to share their views of the conjunction with the world, both in real-time and also in archival photos and videos. The days before and after maximum conjunction also provide wonderful views. (MICHAEL JÄGER/@KOMET123JAGER OF TWITTER)
7.) If you miss it, come back soon. Jupiter/Saturn conjunctions occur every ~20 years; March 15, 2080’s pre-dawn Great Conjunction will appear equally spectacular.
In the predawn sky on March 15, 2080, Jupiter and Saturn will be excellently positioned once again, experiencing another extremely close great conjunction, bringing them within 0.1 degrees of one another. Additionally, the Moon, Uranus, and Mercury all form an approximate line, where a dedicated observer with a clear east/southeast horizon could potentially view all of these worlds at once. (E. SIEGEL / STELLARIUM)
Mostly Mute Monday tells an astronomical story in images, visuals, and no more than 200 words. Talk less; smile more.
Starts With A Bang is written by Ethan Siegel , Ph.D., author of Beyond The Galaxy , and Treknology: The Science of Star Trek from Tricorders to Warp Drive .