2021, April 20: Venus, Gibbous Moon, Mars, Evening Wonders

April 20, 2021: Venus is very low in the west-northwest after sunset.  The gibbous moon is in Cancer, between Regulus and Pollux.  Mars, above the horns of Taurus, approaches the star cluster Messier 35.

2021, April 20: Venus is very low in the west-northwest about 20 minutes after sunset.
Chart Caption – 2021, April 20: Venus is very low in the west-northwest about 20 minutes after sunset.

by Jeffrey L. Hunt

Chicago, Illinois:  Sunrise, 6:02 a.m. CDT; Sunset, 7:38 p.m. CDT.  Check local sources for sunrise and sunset times for your location.

Venus is beginning its evening apparition.  Find it low in the west-northwest about 20 minutes after sunset. You’ll need a clear horizon.  Try to locate the planet first with a binocular.  Then attempt to see it without optical assistance.

Read more about Venus in our summary document.

2021, April 20: The moon, in front of the dim stars of Cancer, is between Regulus and Pollux.
Chart Caption – 2021, April 20: The moon, in front of the dim stars of Cancer, is between Regulus and Pollux.

One hour after sunset, the bright moon, nearly 60% illuminated in the seemingly open space between Regulus and Pollux.  The dim stars of Cancer form the background for the lunar orb.

Regulus, “the prince,” is part of Leo.  On the chart, the bright blue star is at the bottom of a shape resembling a backwards question mark.  The pattern is known as the “Sickle of Leo,” as it resembles a cutting tool.

Pollux is one of the Gemini Twins with Castor, that is out of the frame of the chart.

2021, April 20: The moon is above the horns of Taurus, Elnath and Zeta Tauri (ζ Tau).
Chart Caption – 2021, April 20: The moon is above the horns of Taurus, Elnath and Zeta Tauri (ζ Tau).

Farther west, Mars is less than halfway up in the western sky above the Bull’s horns, Elnath and Zeta Tauri (ζ Tau on the chart).  Mars continues its eastward march through Taurus and in a few days, it enters Gemini.

2021, April 20: Through a binocular Mars is to the lower right of the star cluster M35.
Chart Caption – 2021, April 20: Through a binocular Mars is to the lower right of the star cluster M35.

With a binocular look at Mars and the star cluster Messier 35 (M35), to the upper left of Mars.  Both easily fit into a binocular’s field of view.  The cluster is a small bunch of stars like the Pleiades star cluster and Hyades star cluster, although it is more distant.  In a dark location it looks like a tiny fuzzy cloud to the unaided eye.

Mars passes the M35 cluster in about a week, but each evening the moon’s phase is larger and brighter.  Look each evening as Mars closes in.

Here’s more about Mars during 2021.

Read about Mars during April.

Detailed Note: The moon is at its First Quarter phase at 1:59 a.m. CDT.  One hour before sunrise, Jupiter is over 13° above the east-southeast horizon.  In the starfield, Jupiter is 3.4° to the upper left of Deneb Algiedi, 0.5° to the lower left of μ Cap, and 2.6° to the upper right of ι Aqr.  Saturn – 14.1° to the upper right of Jupiter – is 1.5° to the upper right of θ Cap.  The Ringed Wonder is 18.0° up in the southeast.  Twenty minutes after sunset, brilliant Venus is nearly 2° above the west-northwest horizon as it makes its first evening appearance. An hour after sunset, Mars is about 40° up in the west, 5.0° to the upper right of ζ Tau. The Red Planet is 3.7° to the lower right of M35.  Use a binocular to see the star cluster.  The moon (9.0d, 58%) is nearly 70° up in the south-southwest.  It is between Pollux and Regulus (α Leo, m = 1.3), nearly 17° to the lower left of Pollux and 20° to the upper right of Regulus.  Even with the moon’s brightness, use a binocular to spot the Beehive star cluster (M44, NGC 2632), 3.9° to the lower right of the moon.

Read more about the planets during April 2021.



Categories: Astronomy, Sky Watching

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