December 25, 2020: The gap between bright Jupiter and Saturn widens each evening. Find them low in the southwest as night falls. Bright Mars is to the upper right of the gibbous moon. The Red Planet marches eastward in Pisces.
by Jeffrey L. Hunt
Chicago, Illinois: Sunrise, 7:17 a.m. CST; Sunset, 4:25 p.m. CST. Check local sources for sunrise and sunset times for your location.
As night falls, Jupiter and Saturn are low in the southwest. From about 45 minutes after sunset and for the next hour, they are high enough to be easily seen. Jupiter is the brighter and it is nearly an apparent full-moon diameter (0.4°) to the upper left of Saturn.
The gap between the planets widens each evening. Both are slowly moving eastward. Jupiter revolves around the sun in nearly 12 years, while Saturn’s orbital period is nearly 30 years.
Farther east the bright moon that is 85% illuminated is in the east-southeast. It is over 20° to the lower left of bright Mars.
The Red Planet is marching eastward among the dim stars of Pisces. Use a binocular to see the starfield with the bright moon in the sky. Mars is 4.7° to the upper left of Zeta Piscium (ζ Psc on the chart) and 2.6° to the lower right of dim Pi Piscium (π Psc).
Read about Mars during December.
Detailed note: One hour after sunset, Jupiter is over 10° above the southwest horizon, 0.4° to the upper left of Saturn. In the starfield, Jupiter is 1.8° to the lower right of σ Cap. Mars is 83.4° of ecliptic longitude east of Jupiter among the dim ζ Psc stars of Pisces. The Red Planet is marching eastward. It is 4.7° to the upper left of ζ Psc and 2.6° to the lower right of π Psc. The bright gibbous moon (11.3d, 85%) is over 24° to the lower left of Mars and about 14° to the lower right of Pleiades. Block the moon’s glare to see the star cluster.
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, September 29: Gemini Moon, Evening Planet Pack
September 29, 2021: The thick crescent moon is in the southeast before sunrise, approaching the middle of Gemini. The evening planet pack is visible after sunset.
2021, September 28: Morning Moon, Evening Planets
September 28, 2021: This morning the moon, as it approaches its Last Quarter phase, is high in the south at the Gemini – Taurus border. The evening planet pack – Venus, Jupiter, and Saturn – brightly shine after sunset.
2021, September 27: Moon Between the Horns, Evening Planet Pack
September 27, 2021: Before sunrise this morning, the bright moon seems caught between the horns of Taurus, Elnath and Zeta Tauri. The planet pack, Venus, Jupiter, and Saturn, are visible after sundown.
2021, September 26: Morning Moon, Taurus
September 26, 2021: This morning a bright moon is between the Pleaides and Hyades star clusters.
2021, September 25: Morning Moon, Evening Planet Pack
September 25, 2021: The bright morning moon approaches the Pleiades star cluster and Aldebaran. In the evening sky, brilliant Evening Star Venus, Jupiter, and Saturn are easy to spot.