2021, July 19: Western Planetary Square Dance


July 19, 2021:  Venus continues its dance with Mars and Regulus in the western evening sky.  Look for them forty-five minutes after sunset.

Chart Caption – 2021, July 19: In a binocular brilliant Venus is 2.6° to the right of Regulus and 3.8° to the upper left of Mars.

by Jeffrey L. Hunt

Chicago, Illinois:  Sunrise, 5:33 a.m. CDT; Sunset, 8:21 p.m. CDT.  Check local sources for sunrise and sunset times for your location.

Brilliant Evening Star Venus sparkles in the western sky after sunset.  It continues to climb higher each evening since its first appearance after its superior conjunction about two months ago.

The planet is stepping eastward after its conjunction with Mars a week ago.  Mars moves eastward as well, but at a slower rate.

Both planets are dancing toward the star Regulus.  Venus passes the star in two evenings, while Mars dances with the star in 10 evenings.

Step outside at 45 minutes after sunset.  The bright moon is above the southern horizon.  Venus is low in the western sky.  The brilliant planet is only about 8° above the horizon.

Regulus is 2.6° to the left of Venus.  The Red Planet is 3.8° to the lower right of Earth’s Twin.

In the bright twilight at this hour, Regulus and Mars are likely hiding in the sky’s lively palette.  Use a binocular to find Regulus and Mars.  The trio fits into the field of a binocular.  Place Venus at the center of the field of view.  Mars is to the lower right and Regulus is to the left of Venus.

Regulus and Mars may become visible to the unaided eye during the next 20 minutes as they move lower in the sky.

Tomorrow evening, the trio is more compact as Venus moves closer to Regulus and Mars vainly attempts to catch the faster dancing Venus.

Detailed Daily Note: One hour before sunrise, Saturn – 20° up in the southwest – is retrograding in Capricornus, 2.9° to the lower right of θ Cap.  Bright Jupiter – over 33° above the south-southwest horizon – is 19.7° to the upper left of Saturn.  Retrograding in Aquarius, the Jovian Giant is 2.1° to the upper left of ι Aqr, 4.6° below θ Aqr, and 4.8° to the lower right of σ Aqr.  Thirty minutes before sunrise, Mercury is nearly 6° up in the east-northeast.  With a binocular note that Betelgeuse (α Ori, m = 0.4) is nearly 21° to the right of the speedy planet. The star is making its first morning appearance (heliacal rising). Forty-five minutes after sunset, Venus is over 8° above the west-northwest horizon.  Use a binocular to see Mars 3.8° to the lower right of Venus and Regulus to the left.  The trio fits into the field of a binocular this evening.  An hour after sunset, use a binocular to note that Graffias (β Sco, m = 2.5) and Dschubba (δ Sco, m = 2.3) bracket the moon (10.0d, 79%), nearly one-third of the way up in the south, from above and below. Saturn rises 42 minutes after sunset, followed by Venus setting 51 minutes later.  Have you seen them in nearly opposite directions in the evening sky?  Jupiter rises three minutes after Venus sets.  The Venus – Jupiter opposition (celestial longitude 180° apart) occurs in two evenings.  As midnight approaches, the moon is over 17° above the southwest horizon.  Farther eastward, Saturn is 23.0° up in the south-southeast, while bright Jupiter, 18.0° up in the southeast, is to the Ringed Wonder’s lower left.

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