2021, July 16: Western Planetary Two Step


July 16, 2021: Evening Star Venus races away from Mars and toward Regulus in the western sky.  The moon is near the star Spica.

Chart Caption – 2021, July 16: Forty-five minutes after sunset, brilliant Venus is 2.1° to the upper left of Mars and 6.1° to the lower right of Regulus.

by Jeffrey L. Hunt

Chicago, Illinois:  Sunrise, 5:30 a.m. CDT; Sunset, 8:23 p.m. CDT.  Check local sources for sunrise and sunset times for your location.

The planet two step in the western sky continues this evening as Venus steps away from Mars and toward the star Regulus.  Farther eastward the moon is near Spica.

Step outside about 45 minutes after sunset, brilliant Evening Star Venus sparkles low in the western sky.  At this hour it is over 8° above the western horizon.  Find an observing spot with a clear western horizon.

Use a binocular to find Mars 2.1° to the lower right of the dazzling planet.  Regulus is 6.1° to the upper left of Venus.  In two evenings, the trio easily fits into the same binocular field.  This evening Venus and Mars or Venus and Regulus fit into a field of view.

Venus moves eastward about twice the speed of Mars.  After their conjunction, Venus steps away from Mars toward Regulus, while the Red Planet trails the faster moving planet.

Chart Caption – 2021, July 16: The thick crescent moon is 6.4° to the upper right of Spica.

Farther eastward, the moon, nearing its First Quarter phase, is nearly one-third of the way up in the southwest.  The lunar orb is 6.4° to the upper right of Spica.

By 80 minutes after sunset, Venus and Saturn are visible on opposite parts of the sky.  The brilliant planet is very low in the west-northwest, while Saturn is about 5° up in the east-southeast. Can you find both of them?

In five evenings, Jupiter and Venus are at opposition, 180° apart along the ecliptic.  This signals that both planets are soon visible in the evening together.  Begin looking for them at the same time later in the month. Venus, Saturn, and Jupiter appear in the evening sky until Venus disappears into the sun’s glare during early 2022.

As the calendar day ends, Saturn is 22° above the southeastern horizon, while Jupiter is to the Ring Wonder’s lower left.

Detailed Daily Note: One hour before sunrise, Jupiter is over 34° up in the south-southwest.  It is retrograding in Aquarius, 2.3° to the upper left of ι Aqr, 4.5° below θ Aqr, and 4.5° to the lower right of σ Aqr.  Through a binocular note that the Jovian Giant is to the lower right of a line from 38 Aqr to 42 Aqr.  The planet is clearly moving westward along the ecliptic.  Note its position tomorrow morning in comparison to this morning.  Saturn is 19.7° to the lower right of Jupiter.  Clearly retrograding, the Ringed Wonder, about 22° up in the southwest, is 2.7° to the lower right of θ Cap.  Fifteen minutes later, Mercury (m = −0.8) is nearly 5° up in the east-northeast.  One hour after sunset, the moon (7.0d, 46%) is over 29° above the southwest horizon, 6.4° to the upper right of Spica (α Vir, m = 1.0).  Meanwhile, brilliant Venus is less than 6.0° above the west-northwest horizon, 2.1° to the upper left of Mars and 6.1° to the lower right of Regulus.  Saturn rises 52 minutes after sunset, while Venus sets 42 minutes later.  Have you seen them together in the sky before Venus sets?  Jupiter rises 106 minutes after sunset.  Jupiter’s rising time and Venus’ setting time are converging.  They are at opposition in five evenings.  This signals that the pair begins to appear in the sky at the same time, Jupiter in the eastern sky and Venus is in the western sky.  Venus, Jupiter, and Saturn appear in the evening sky until Venus races between Earth and the sun during early January 2022.  As midnight approaches, the moon is low in the west-southwest.  Jupiter is over 16° up in the east-southeast, while Saturn, nearly 22° up in the southeast, is to the Jovian Giant’s upper right.

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