2021, March 20: Moon Between Horns

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.