April 30, 2021: Evening Star Venus and Mercury are low in the west-northwest after sunset. Venus is beginning its evening appearance and Mercury is enroute to its best evening appearance of the year. After night falls, Mars is in the west in Gemini. Through a binocular, Mars is visible near the star cluster Messier 35.
by Jeffrey L. Hunt
Chicago, Illinois: Sunrise, 5:48 a.m. CDT; Sunset, 7:49 p.m. CDT. Check local sources for sunrise and sunset times for your location.
Venus seems to take the long course into the evening sky. Look for it about 20 minutes after sunset, over 4° up in the west-northwest. Locate it first with a binocular. Can you see it during this bright twilight without optical help? Bright Mercury is 4.5° above Mercury. With a wide-field binocular both planets appear in the same field of view.
Mercury is enroute to its best evening appearance of the year. Next month it appears in a darker evening sky.
Read more about Venus in our summary document.
As the sky darkens and Venus and Mercury set in the west-northwest, Mars becomes visible along with the stars across the sky.
The Red Planet, less than 40° up in the west, is near the feet of Gemini. It is marching eastward in the constellation. The planet is 2.5° to the upper right of Propus, “the projecting foot,” (η Gem on the chart) and Tejat Posterior, “the heel,” (μ Gem).
In a binocular, Mars is now past Messier 35 (M35). It is 2.4° to the upper left of the star cluster.
Venus is slowly closing the gap to Mars. At April’s conclusion, the gap between the two planets is over 44. As Venus appears higher in the sky each night, watch the gap between the two worlds close.
Here’s more about Mars during 2021.
Read about Mars during April.
Detailed Note: One hour before sunrise, the moon (18.3d, 85%) is over 20° above the southern horizon. The lunar orb is 16.0° to the upper left of Antares and 10.6° to the right of Kaus Borealis (λ Sgr, m = 2.8), the star at the top of the lid of the Teapot of Sagittarius. At this hour, Jupiter is nearly 17° above the southeast horizon. It is moving eastward in Aquarius, 4.8° to the left of Deneb Algiedi, 2.1° to the lower left of μ Cap, and 1.5° to the upper right of ι Aqr. Saturn is 15.2° of ecliptic longitude west of Jupiter, to the upper right of the Jovian Giant in the sky. Saturn is slowly creeping toward θ Cap. This morning the gap is 1.0°. The sun is in the sky for one minute longer than 14 hours. Twenty minutes after sunset, brilliant Venus is over 4° above the west-northwest horizon. Have you observed it without a binocular? Mercury (m = −1.1) is 4.5° above Venus. As the sky darkens further, Mars is less than 40° up in the west among the stars of Gemini. It is 2.5° to the upper right of Propus and 2.4° to the right of Tejat Posterior. Use a binocular to locate the star cluster M35, 2.4° to the lower right of Mars. The month ends with Mars 44.5° of ecliptic longitude east of Venus. As Venus becomes easier to see, watch it close the gap to Mars.
Read more about the planets during April 2021
October 23, 2021: This morning the bright moon is near the Pleiades star cluster. Mercury is making its best morning appearance. In the evening sky, Venus, Jupiter and Saturn are easy to spot.
October 22. 2021: Speedy Mercury is low in the east before sunrise. It is putting on its best morning performance of the year. Arcturus, in the east-northeast, is about the same altitude as Mercury.
October 21-November 1, 2021: Brilliant Venus steps through Ophiuchus to the upper left of the star Antares in the southwest after sunset . Afterward, the planet steps farther eastward.
October 21, 2021: The bright moon is low in the west about an hour before sunrise. Mercury is in the east at about the same altitude as Arcturus. Venus, Saturn, and Jupiter shine from the evening sky.
December 18, 2021: This is the anticipated launch date of the James Webb Space Telescope, the largest and most sophisticated space telescope view the universe.