2021, August 13: Evening Sky, Bright Planets

August 13, 2021: This evening the crescent moon appears between Evening Star Venus and Spica as the lunar slice dances eastward.  Jupiter and Saturn are in the southeastern sky.

2021, August 13: The crescent moon is 7.4° to the upper left of Spica. Brilliant Venus is 26.7° to the lower right of Spica.
Chart Caption – 2021, August 13: The crescent moon is 7.4° to the upper left of Spica. Brilliant Venus is 26.7° to the lower right of Spica.

by Jeffrey L. Hunt

Chicago, Illinois:  Sunrise, 5:57 a.m. CDT; Sunset, 7:53 p.m. CDT.  Check local sources for sunrise and sunset times for your location.

The crescent moon, over 30% illuminated this evening, is over 20° up in the west as night falls.  The lunar crescent continues to grow as the moon steps farther eastward each evening.

The star Spica is 7.4° to the lower right of the lunar slice.  It is the brightest in the constellation Virgo.  The name is translated as “the ear of corn.”

Porrima, also known as Gamma Virginis, is to the right of Spica. In his 1944 article of star name translations and meanings, George Davis, wrote that the star has “the name of a Roman nymph or goddess of prophecy and childbirth” (p. 23).

This evening brilliant Venus is about 8° up in the west.  It is 0.1° above the star Zavijava (β Vir on the chart), also known as Beta Virginis.  Davis wrote that the name means “the corner of the barking dog” (p. 23).

2021, August 13: Through a binocular, Venus is 0.1° above Zavijava.
Chart Caption – 2021, August 13: Through a binocular, Venus is 0.1° above Zavijava.

Use a binocular to see Venus and the star.  The pair appears close together, but they are very far apart in space.  Using the speed of light to estimate distances, the light from Venus crosses the inner solar system in over 10 minutes.  Light from Zavijava takes 36 years to reach Earth.

2021, August 13: Jupiter and Saturn are in the southeast after sunset.
Chart Caption – 2021, August 13: Jupiter and Saturn are in the southeast after sunset.

Note that Jupiter and Saturn continue to enter the evening sky.  Look for them in the southeast.  Jupiter, the brighter of the pair, is to the lower left of Saturn.  The gap between them is over 17°.  Your fist at arm’s length is about 10°.

Detailed Daily Jupiter, retrograding in Aquarius, is nearing the Aquarius – Capricornus border.  One hour before sunrise, the Jovian Giant is nearly 17° up in the southwest.  In the starfield, it is 1.3° to the lower right of ι Aqr and 4.4° to the upper left of Deneb Algedi. Forty-five minutes after sunset, the waxing crescent moon (5.5d, 32%) is over 20° up in the southwest and 7.4° to the upper left of Spica.  “The ear of corn” is over 15° above the west-southwest horizon.  Brilliant Venus, 8.0° up in the west, is 0.1° above Zavijava and 26.7° to the lower right of Spica.  Venus continues to advance eastward daily at about 1.2°.  Farther eastward along the ecliptic, Saturn is over 12° up in the southeast, while Jupiter is nearly 5° up in the east-southeast.  Around midnight, Saturn is about one-third of the way up in the south, 4.8° to the lower right of θ Cap and 1.6° to the lower left of υ Cap.  Jupiter is over 30° above the south-southeast horizon.

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