December 18, 2020: The crescent moon overlooks the impending Jupiter – Saturn Great Conjunction during the early evening hours. Mars is in the southeast after sunset. Great Conjunction Countdown: 3 days!
by Jeffrey L. Hunt
Chicago, Illinois: Sunrise, 7:14 a.m. CST; Sunset, 4:22 p.m. CST. Check local sources for sunrise and sunset times for your location.
As night falls, the crescent moon, that is 21% illuminated, is to the upper left of the impending Jupiter – Saturn Great Conjunction in 3 evenings.
About 45 minutes after sunset, Jupiter is the bright star in the southwest. Saturn is immediately to the upper left of its brighter companion planet. The planets are 0.3° apart, that’s less than the moon’s size in the sky. The tip of your pinky finger held at arm’s length covers the two planets.
Note the early sunset time and locate the planets before they appear too low in the sky and eventually set. The best time window to see them is 45 minutes after sunset for the next 60 minutes. Jupiter sets 2 hours, 30 minutes after sunset this evening.
Great Conjunction Countdown: 3 days!
Farther eastward, Mars continues its eastward march in Pisces. Find the planet about halfway up in the sky about one hour after sunset. With a binocular note that it is to the upper left of dim Zeta Piscium (ζ Psc on the chart) and Epsilon Piscium (ε Psc). It continues to move away from those stars and toward Aries that is marked by Hamal, its brightest star.
Read about Mars during December.
Detailed note: In the evening, look for Jupiter and Saturn in the southwest as the sky darkens after sunset. Jupiter moved into Capricornus from Sagittarius today. The planet pair is about 15° up in the southwest. The Jupiter – Saturn gap is 0.3°, with Jupiter to Saturn’s lower right. Great Conjunction Countdown: 3 days. The moon (4.3d, 21%) is over 20° to the upper left of Jupiter. Farther east, Mars is over 48° up in the southeast. It is moving eastward among the stars of Pisces. The Red Planet is 2.1° to the upper left of ζ Psc and 4.6° to the lower left of ε Psc.
For more about the Great Conjunction, read our feature article. This is the closest Jupiter – Saturn conjunction since 1623.
Read more about the planets during December.
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