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.
- 2023, October 20: Jupiter’s Double Shadows, Mercury at Superior ConjunctionOctober 20: After midnight, Jupiter’s moons’ shadows dance across the cloud tops. Mercury is at superior conjunction.
- 2023, October 19: Poured Moon, See Planet UranusOctober 19: Sagittarius seems to pour the moon into the sky this evening. Find Uranus with a binocular.
- 2023, October 18: Moon-Antares Conjunction, Bright PlanetsOctober 18, 2023: The moon is near Antares after sunset. Venus, Jupiter, and Saturn are in the sky during the nighttime hours.
- 2023, October 17: Scorpion MoonOctober 17, 2023: The crescent moon is with Scorpius during evening twilight. Venus and Jupiter gleam from the predawn sky.
- 2023, October 16: Venus in Starry ConjunctionOctober 16, 2023: Venus passes a star in Leo before sunrise. A crescent moon is low in the western sky during evening twilight.