March 20, 2021: After sunset, look for the nearly half-full moon high in the southwest. It is between the horns of the Bull, Elnath and Zeta Tauri. Mars is to the lower right of the moon. The Red Planet passes to the upper right of Aldebaran, the constellation’s brightest star.
by Jeffrey L. Hunt
Chicago, Illinois: Sunrise, 6:54 a.m. CDT; Sunset, 7:03 p.m. CDT. Check local sources for sunrise and sunset times for your location.
This evening the nearly first quarter moon (44%) seems to be caught between the horns of Taurus, Elnath, “the one butting with horns,” and Zeta Tauri (ζ Tau on the chart). An hour after sunset, look for the moon over two-thirds of the way up in the southwestern sky.
Mars is over 14° to the lower right of thick lunar crescent. This evening it has a conjunction with Aldebaran, “the follower.” The gap is 6.9°. The Red Planet is to the upper right of the star.
Mars continues its eastward march through the constellation. Use a binocular to spot it 2.6° to the lower right of Tau Tauri (τ Tau).
Here’s more about Mars during 2021.
Read about Mars during March.
Detailed Note: The sun is at 0° of ecliptic longitude at 4:37 a.m. CDT, signaling the beginning of astronomical spring (Vernal Equinox) in the northern hemisphere. During mid-twilight, about 45 minutes before sunrise, Jupiter and Saturn are low in the southeastern sky. Saturn is 11° up in the southeast. Jupiter is 10.4° of ecliptic longitude east of Saturn. The Giant Planet is nearly 7° up in the east-southeast, 3.0° to the lower left of ι Cap, while Saturn is 3.7° to the upper right of θ Cap. An hour after sunset, the moon (7.6d, 44%) – between the horns of Taurus – is over two-thirds of the way up in the southwest. It is 3.0° to the upper right of Zeta Tauri (ζ Tau, m = 2.0) and 4.8° to the lower right of Elnath (“the one butting with horns,” β Tau, m =1.6). Mars is over 14° to the lower right of the thick lunar crescent. This evening, Mars passes 6.9° to the upper right of Aldebaran. The planet is nearly 10° to the upper left of Alcyone and the Pleiades. Among the dimmer stars, the Red Planet is 2.6° to the lower right of τ Tau.
Read more about the planets during March 2021.
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.