May 4, 2021: Three planets are visible after sunset. Brilliant Venus is low in the west-northwest after sundown. Mercury is above Venus. It is visible lower as the sky darkens. As night falls, Mars is over a third of the way up in the west, under Castor and Pollux, the Gemini Twins.
by Jeffrey L. Hunt
Chicago, Illinois: Sunrise, 5:43 a.m. CDT; Sunset, 7:53 p.m. CDT. Check local sources for sunrise and sunset times for your location.
Five planets are visible during a 24-hour period. This evening, Venus and Mercury are visible during brighter twilight. Mars is visible when the sky is darker in the western sky.
Twenty minutes after sunset, brilliant Venus is about 5° up in the west-northwest. The window to see Venus is narrow, as it sets about 50 minutes after sunset. A binocular may be needed to initially see the brilliant planet.
Read more about Venus in our summary document.
Bright Mercury is nearly 7° to the upper left of Venus. The planet is enroute to its best evening appearance of the year. This speedy planet sets about 90 minutes after sunset. As the sky darkens, it is visible lower in the west-northwest sky.
Forty-five minutes after sunset, Mercury is about 7° above the horizon. With a binocular, spot the Pleiades star cluster to the lower right of Mercury. The cluster is not in the best observing location. The gap from Mercury to the cluster’s brightest star, Alcyone (η Tau on the chart), is 4.4°.
Here’s more about Mercury during May 2021.
When the sky is darker, around an hour after sunset, Mars is over 35° up in the west among the stars of Gemini, under Castor and Pollux. The planet is moving eastward compared to these stars. The plane of the solar system, known as the ecliptic, generally cuts across the constellation from the lower right corner of the diagram to the upper left.
Mars’ eastward march takes it from tonight’s place to the lower left of Pollux by month’s end.
This evening, Mars is 2.6° to the upper right of Tejat Posterior (μ Gem on the chart) and 3.2° to the lower right of Mebsuta (ε Gem).
Tomorrow morning look for the moon near Jupiter and Saturn.
Here’s more about Mars during 2021.
Detailed Note: One hour before sunrise, the moon (22.3d, 48%) is over 15° above the southeastern horizon. Bright Jupiter is 8.9° to the moon’s upper left, while Saturn is 9.6° to the upper right of the lunar orb. In the starfield, Saturn is 0.9° to the right of θ Cap. Jupiter is 1.3° above ι Aqr. Twenty minutes after sunset, Venus is nearly 5° up in the west-northwest. Mercury (m = −0.8) is 6.9° to the upper left of Venus. Mercury sets about 90 minutes after sunset. As the sky darkens it is lower in the sky above the west-northwest horizon. By 30 minutes after sunset, Venus is nearly 4° above the horizon, while Mercury is 10.0° up in the sky. Forty-five minutes after sunset, Mercury is over 7° in altitude and 4.4° to the upper left of η Tau. By one hour after sunset, Mercury is about 5° above the horizon. At this hour, Mars is visible over 35° to the upper left of Mercury among the stars of Gemini. The Red Planet is 2.6° to the upper right of μ Gem and 3.2° to the lower right of ε Gem.
Read more about the planets during May 2021.
July 26, 2021: Four bright planets are in the evening sky. Mars closes in on Regulus for their conjunction in three evenings. Brilliant Evening Star Venus appears to the upper left of the impending Mars – Regulus conjunction. Saturn and Jupiter are low in the southeastern sky after sunset.
July 25, 2021: Four evenings before its conjunction with Regulus, find Mars in the western sky to the lower right of Venus. As the calendar day ends, look for the moon below bright Jupiter.
July 24, 2021: After sunset, Venus and Mars are in the western sky. A little later during evening hours, the moon is near Jupiter and Saturn in the southeast.
July 23, 2021: Four bright planets are visible during evening hours. Venus and Mars are in the western sky after sunset. A little later, the moon is near Saturn and Jupiter in the southeastern sky.
July 29, 2021: Jupiter and Mars are 180° apart along the ecliptic. Dim Mars sets in the west-northwest as Jupiter rises in the east-southeast. This event signals that soon both appear in the sky simultaneously.