2020, December 17: Jupiter, Saturn, and Crescent Moon

Jupiter, Saturn, Moon, December 17, 2020
2020, December 17: After sunset, Jupiter and Saturn are in the southwest. The moon is to the upper left of the planet pair.

December 17, 2020: Jupiter and Saturn appear again with the crescent moon although the moon’s spacing is larger than last night.  Jupiter continues to close in on Saturn.  Great Conjunction Countdown: 4 days!

by Jeffrey L. Hunt

Chicago, Illinois:  Sunrise, 7:13 a.m. CST; Sunset, 4:21 p.m. CST.  Check local sources for sunrise and sunset times for your location.

2020, December 17: Jupiter, Saturn, and the crescent moon. The Great Conjunction of Jupiter and Saturn is 4 days away.
2020, December 17: Jupiter, Saturn, and the crescent moon.

Jupiter slowly closes the gap to Saturn.  Find them in the southwest, beginning about 45 minutes after sunset.  Jupiter is the bright “star” low in the sky.  Saturn is to the upper left of its brighter companion. 

2020, December 17: Jupiter, Saturn, and the crescent moon.
2020, December 17: Jupiter, Saturn, and the crescent moon.

The planets are closer in the sky than the moon’s apparent size.  Extend a pinky finger to arm’s length.  The tip of your finger covers both planets.  It’s not often that two planets appear this close in the sky.

Great Conjunction Countdown: 4 days!

This evening the crescent moon, that is 13% illuminated, is to the upper left of Jupiter and Saturn.

Mars, December 17, 2020
2020, December 17: After sunset, Mars is over 47° up in the southeast, 1.8° to the upper left of Zeta Piscium (ζ Psc) and 4.0° to the lower left of Epsilon (ε Psc).

Farther east, Mars marches eastward in front of the stars of Pisces.  It is moving away from Zeta Piscium (ζ Psc on the chart) and Epsilon Piscium (ε Psc).

The Red Planet is over halfway up in the southeast as night falls.  The planet is south about three hours after sunset.  It sets in the west a few hours after midnight and over five hours before sunrise.

Read about Mars during December.

Detailed note: Forty-five minutes after sunset, Jupiter is nearly 16° up in the southwest, 0.4° to the lower right of Saturn. Great Conjunction Countdown: 4 days. The lunar crescent (3.3d, 13%) is over 10° to the upper left of Jupiter. As the sky darkens further, Mars is over 47° up in the southeast, 1.8° to the upper left of ζ Psc and 4.0° 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.

2021, May 13: Brilliant Venus, Mercury, and the crescent moon in the evening sky.

2021, August 3: Four Evening Planets: Venus, Mars, Saturn, Jupiter

August 3, 2021:  Four planets appear in the evening sky.  Brilliant Evening Star Venus and dim Mars are in the west after sunset.  A little later during the evening, Saturn and Jupiter are easily visible in the southeast.

Saturn (NASA)

2021, August 2: Saturn at Opposition

August 2, 2021: Saturn is at opposition with the sun.  Earth is between the sun and the planet.

2020, July 17: The crescent moon appears near Venus before sunrise. The night portion of the moon is gently illuminated by earthshine.

2021: August 1 – 6: Morning Moon, Bright Stars

August 1 – 6, 2021:  The morning moon wanes toward its New moon phase in the eastern sky.  It passes the bright stars that are prominent in the evening sky during the winter season in the northern hemisphere.  The stars have been making their first appearances in the morning sky during summer.  At this hour, Procyon and bright Sirius are the last stellar duo to appear.

2021, July 8: The flowers celebrate summer.

2021, August 6: Summer’s Midpoint

August 6, 2021:  In the northern hemisphere, summer’s midpoint occurs today at 6:27 p.m. CDT.

The moon and Spica, December 10, 2020

2021, July 31: Morning Sky, Moon, Mira, Uranus

July 31, 2021:  The slightly gibbous moon, nearing its Last Quarter phase, is in the southeast as morning twilight begins.  It is near the planet Uranus, easily within reach of a binocular.  Mira, a variable star, reaches its brightest next month.



Categories: Astronomy, Sky Watching

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