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.
Read more about the planets during December.
- 2023, December 26: Cold Moon, Venus, Jupiter, SaturnDecember 26, 2023: The Cold Moon is visible during the nighttime hours. Venus shines before sunrise while Jupiter and Saturn are visible after sundown.
- 2023, December 25: Telescope First Light, Bright PlanetsDecember 25, 2023: For sky watchers with new telescopes, here’s what to look at before dawn or after sunset.
- 2023, December 24: Morning Moon, Pleiades, Antares Heliacal RisingDecember 24, 2023: The moon appears near the Pleiades star cluster during the earlier morning hours. Antares is at its first morning appearance, known as the heliacal rising.
- 2023, December 23: Check out Planet Uranus, Pleiades near MoonDecember 23, 2023: Look for the planet Uranus and the Pleiades star cluster through a binocular during nighttime hours.
- 2023, December 22: Mercury at Inferior Conjunction, Bright Jupiter, Gibbous MoonDecember 22, 2023: Mercury is between Earth and Sun, known as inferior conjunction. Jupiter and the gibbous moon are celestial companions during nighttime hours.