December 16, 2020: The crescent moon joins Jupiter and Saturn as a prelude to the Great Conjunction in 5 evenings. The moon is visible below the planets. Mars is in the southeast after sunset.
by Jeffrey L. Hunt
Chicago, Illinois: Sunrise, 7:12 a.m. CST; Sunset, 4:21 p.m. CST. Check local sources for sunrise and sunset times for your location.
Just five days before the Great Conjunction of Jupiter and Saturn, the moon makes a dramatic appearance with the converging planets. From about 45 minutes after sunset to about 90 minutes after the sun’s nightly disappearance, the moon can be seen below the planet pair.
Not until March 17, 2080, does the moon appear near a very close grouping of Jupiter and Saturn. The moon passes Jupiter and Saturn every month, but the two planets are near each other every 19.6 years. Other Great Conjunctions occur in 2040 and 2060, but the conjunction distance is over 1°.
Jupiter sets at about 7 p.m. CST in Chicago, Illinois, about 2.5 hours after sunset for other locations.
The crescent moon is only 7% illuminated and over 5° below the bright planet Jupiter. Saturn is 0.5° to the upper left of the Jovian Giant. The separation of the two planets is about the same as the moon’s width in the sky.
The Great Conjunction occurs in 5 evenings! Jupiter continues to slowly close the gap to Saturn for this once-in-a-generation meeting of the two planets.
Photographers can capture the trio together with time exposures ranging from a few seconds to about 10 seconds on a tripod-mounted camera. The longer exposures will capture earthshine, the glow of reflected sunlight from Earth’s features that gently illuminates the lunar night.
Farther east, bright Mars is about halfway up in the east. It is marching eastward in front of the starry background of Pisces. In the starfield, the Red Planet is 1.5° to the upper left of Zeta Piscium (ζ Psc on the chart) and 3.7° to the lower left of Epsilon Piscium (ε Psc).
The Red Planet is in the south about three hours after sunset. It sets in the west over 5 hours before sunrise.
Read about Mars during December.
Detailed note: Jupiter is 16° up in the southwest, 0.5° to the lower right of Saturn. Great Conjunction Countdown: 5 days. One after sunset, the crescent moon (2.3d, 7%) is 5.4° below Jupiter. Farther east, Mars (m = −0.6) is over 45° up in the southeast. In the starfield, the Red Planet is 1.5° to the upper left of ζ Psc and 3.7° to the lower left of ε Psc.
Read more about the planets during December.
April 25, 2021: Mercury passes Evening Star Venus this evening after sunset. Look low in the western sky about 20 minutes after sunset. Mars is marching eastward in Gemini, near the star cluster Messier 35. The bright moon is near Spica.
April 25, 2021: Morning planets Jupiter and Saturn are in the southeast before sunrise. Jupiter is in front of the stars of Aquarius, while Saturn’s starry background is Capricornus.
April 24, 2021: Brilliant Evening Star Venus and bright Mercury are entering the evening sky. They are low in the west-northwest during evening twilight. The bright moon is in the southeast in Virgo. Mars moves into Gemini as it approaches the star cluster Messier 35.
April 24, 2021: The bright gibbous moon is near a star in Virgo during the early morning. From parts of the Western Hemisphere, the moon covers the star. Before sunrise, bright morning planets, Jupiter and Saturn are in the southeast before sunrise.
April 23, 2021: Evening Star Venus and Mercury are entering the evening sky. They are found very low in the west-northwest after sunset. The bright moon is in the southeastern sky during the early evening. Mars is moving toward the star cluster Messier 35.