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.
December 28, 2021: The Great Andromeda Galaxy is nearly overhead at the end of the evening twilight.
December 29, 2021: The morning crescent moon approaches Scorpius and Mars. In the evening sky, four evening planets – Venus, Mercury, Saturn, and Jupiter – are lined up in the southwest. Venus is rapidly leaving the evening sky.
November 28, 2021: During twilight this evening, the three bright evening planets – Venus, Saturn, and Jupiter – are on parade in the southwestern sky.
December 28, 2021: Brilliant Venus is quickly slipping from the evening sky. Mercury appears beneath Venus after sunset. This duo is joined by Jupiter and Saturn. In the morning, Mars is near Antares and the moon near Spica.
December 27, 2021: The Red Planet Mars passes Antares this morning before sunrise. At the same hour, the moon is near Spica. The three bright planets – Venus, Saturn, and Jupiter – are in the evening sky.