January 1, 2021: Jupiter and Saturn are becoming more difficult to see as Jupiter opens a 1.2° gap after their Great Conjunction on the winter solstice. Look early after sunset. Find Mars high in the southeast.
by Jeffrey L. Hunt
Chicago, Illinois: Sunrise, 7:18 a.m. CST; Sunset, 4:31 p.m. CST. Check local sources for sunrise and sunset times for your location.
Bright Jupiter and Saturn, after their Great Conjunction 11 days ago, start the evening low in the southwest as night falls. Bright Jupiter has opened a gap of 1.2° to dimmer Saturn.
We are making our last call to see the planets, mainly because of their altitude. Unless you have a horizon free from obstructions, the planets have likely disappeared from your view.
The days are numbered to see Jupiter and Saturn. Before the month ends, both worlds disappear into the sun’s brightness as they reach their solar conjunctions.
The window to see the planets narrows. Jupiter sets about 100 minutes after sunset. Before they set, the window begins about 45 minutes after sunset and lasts 20-25 minutes before the planets are too low to be seen easily, especially dimmer Saturn.
They can be seen as early as 30 minutes after sunset, but that requires a binocular to pick out Saturn during bright twilight.
Mercury joins the Jovian duo in several days and the best views occur about 30 minutes after sunset. If you plan to see the speedy planet near Jupiter and Saturn, begin looking earlier with a binocular to locate Saturn in a brighter sky.
As the sky darkens further, find Mars nearly two-thirds of the way up in the southeastern sky. The planet continues its eastward march in Pisces near the Aries border. Use a binocular to spot the planet against the dim star field that includes Pi Piscium (π Psc) and Omicron Piscium (ο Psc).
Mars is high in the south about 2 hours after sunset. It sets in the west about 6 hours before sunrise.
Read about Mars during January.
Here is a summary of the planets’ activities during January 2021.
Detailed Note: Forty-five minutes after sunset, Jupiter (m = −2.0) is less than 9° up in the southwest, 1.2° to the upper left of Saturn (m = 0.6). As the sky darkens further, Mars (m = −0.2) – 80.9° of ecliptic longitude east of Jupiter – is over 55° up in the southeast. It is marching eastward in Pisces. In the starfield, it is 1.1° to the lower left of Pi Piscium (π Psc, m =5.5) and 2.5° above Omicron Piscium (ο Psc, m = 4.2). Four hours after sunset (8:30 p.m. CST), the gibbous moon (18.4d, 90%), in western Leo, is over 12° in altitude in the east-northeast.
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.