March 4, 2021: Evening planet Mars passes the Pleiades star cluster and its brightest star Alcyone.
by Jeffrey L. Hunt
Chicago, Illinois: Sunrise, 6:20a.m. CST; Sunset, 5:45 p.m. CST. Check local sources for sunrise and sunset times for your location.
In the evening sky, Mars is the lone bright planet. It is moving eastward in front of the stars of Taurus and close to the Pleiades. While not as bright as it was at the beginning of the year, it is easy to spot with the bright winter stars.
Here’s where to find it: Step outside about an hour after sunset. (The planet and surrounding stars do not set until over 6 hours after sunset, so there’s a wide window to see it.) Look high in the west-southwest. A small group of dim, tightly packed stars will catch your eye. This is the Pleiades star cluster. Mars is to the lower left of the cluster.
Tonight, Mars passes the brightest star in the cluster, Alcyone. (Do not confuse Mars with Aldebaran, the reddish star to the upper left of the Pleiades) The separation is 2.6°. It’s not a close conjunction. Anytime a bright planet treks through the field is an interesting view.
Venus trekked through the region about a year ago.
The grouping is easily visible to the unaided eye. A binocular reveals many blue, and blue-white stars in the Pleiades star cluster.
Here’s more about Mars during 2021.
Read about Mars during March.
Detailed Note: One hour before sunrise, the moon (20.7d, 68%) is about 30° up in the south-southwest. It is between Gamma Librae (γ Lib, m = 3.9) and Iota Librae (ι Lib, m = 4.5). The lunar orb is 3.9° to the lower right of γ Lib and 3.5° to the upper left of ι Lib. Three planets are in the east-southeast before sunrise. Forty-five minutes before sunrise, Saturn is over 6° in altitude in the east-southeast. Fifteen minutes later, Jupiter is nearly 5° in altitude, over 8° to the lower left of Saturn. Use a binocular to find it with Mercury 0.6° to Jupiter’s upper right. One hour after sunset, Mars is less than 60° up in the west-southwest, 2.6° to the lower left of Alcyone, as the Red Planet passes the star this evening.
Read more about the planets during March 2021.
March 18, 2021: Jupiter and Saturn are visible in the southeastern sky as sunup approaches. Jupiter is the brighter planet, but it is low in the east-southeast. Saturn is to the Jovian Giant’s upper right. During the early evening, the waxing crescent moon is in the western sky near the Pleiades star cluster and below Mars. The Red Planet is moving eastward in Taurus.
March 17, 2021: Jupiter and Saturn are low in the southeastern sky before sunrise. During the early evening the lunar crescent is about one-third of the way up in the sky to the upper left of Hamal, the brightest star in Aries. Mars is higher in the sky in Taurus. This evening it makes a pretty triangle with two dim stars.
March 16, 2021: Jupiter and Saturn are low in the southeastern sky before sunrise. During the evening the lunar crescent displays earthshine, while Mars continues to march eastward through the starfields of Taurus.