2021, January 13: Evening Planets

2021, January 13: After sunset, Jupiter and Mercury are low in the west-southwest. The Jupiter – Mercury gap is 3.3°.

January 13, 2021:  Mercury and Jupiter can be found in the west-southwest during bright evening twilight.  Mars is higher in the sky when the sky is darker.  It is nearing the planet Uranus.

by Jeffrey L. Hunt

Chicago, Illinois:  Sunrise, 7:16 a.m. CST; Sunset, 4:43 p.m. CST.  Check local sources for sunrise and sunset times for your location.

Mercury and Jupiter appear low in the west-southwest as night falls.  To the unaided eye, the planets appear as overly bright stars.

Thirty minutes after sunset, Jupiter is less than 5° in altitude.  Find a clear horizon to see them.  Mercury is over 3° to the upper left of brighter Jupiter.  This observation is difficult to make.  Use a binocular to initially spot these planets. Catch Jupiter before it leaves the evening sky.

As the sky darkens further, Mars is high in the south-southeast in a dim star field in Aries.  The planet passes the star Gamma Arietis (γ Ari on the chart).  The gap is wide, 6.0°, but γ Ari, Beta Arietis, and Hamal are the three brightest stars in the constellation.  The trio is far from the ecliptic, where the planets appear in the sky.

2021, January 13: Mars is 6.0° to the lower left of Gamma Arietis (γ Ari) and 3.7° to the upper right of Uranus.

Mars is approaching dim Uranus.  The distant planet is at the limit of human eyesight, but not considered one of the “naked-eye planets.”  Use a binocular to find an aquamarine “star” 3.7° to the lower left of Mars.  The star 19 Arietis (19 Ari) is shown on the chart for scale.

A telescope needs about 100x magnification to see the planet’s spherical shape,

Mars passes the distant world in a week, although the moon is in the vicinity on that evening.

Read about Mars during January.

Detailed Note: Thirty minutes after sunset, Jupiter is over 4° in altitude above the west-southwest horizon, 3.3° to the lower right of Mercury. One hour after sunset, Mars (m = 0.1) is 6.0° to the lower left of γ Ari.  Look for the planet and the star over 60° up in the south-southeast. Uranus is 3.7° to the lower left of Mars.

Read more about the planets during January.


Leave a ReplyCancel reply