2021, July 15: Evening Celestial Wheel Turns


2021, July 15:  Evening Celestial Wheel Turns

July 15, 2021:  Each evening the moon continues to move eastward with a waxing phase while Venus and Mars dance in the western sky.

Chart Caption – 2021, July 15: Forty-five minutes after sundown, brilliant Venus is low in the west-northwest, 1.5° to the upper left of Mars and 7.3° to the lower right of Regulus.

by Jeffrey L. Hunt

Chicago, Illinois:  Sunrise, 5:29 a.m. CDT; Sunset, 8:24 p.m. CDT.  Check local sources for sunrise and sunset times for your location.

The movement of the moon and planets in the western sky demonstrates the intricate, yet delicate, celestial clockwork.

The crescent moon’s phase grows each evening as it moves farther eastward from the sunset point.

Lower in the western sky, Venus is stepping away from Mars toward Regulus.  Mars is moving toward the star as well, but at a slower rate.

Forty-five minutes after sunset, set outside and look westward.  The moon, 35% illuminated, is nearly one-third of the way up in the west-southwest.

Brilliant Venus is low in the west-northwest. Its visual intensity punches through the colors of evening twilight.  At this sky brightness, use a binocular to see dimmer Mars, 1.5° to the lower right of the brilliant planet.  The star Regulus is 7.3° to the upper left of Venus.  You can either fit Venus and Mars in the same binocular field or just fit Venus and Regulus, Venus to the lower right section of the field, and Regulus to the upper left.

As the sky darkens further, the planets and Regulus are lower in the sky.  Possibly Mars and Regulus appear through the dimming light before they set.

Chart Caption – 2021, July 15: One hour after sunset, look for Porrima (γ Vir), 4.1° to the left of the moon. Spica is nearby.

The moon is in front of the constellation Virgo.  It is 4.1° to the right of Porrima, also known as Gamma Virginis (γ Vir on the chart), and over 18° to the right of Spica.  Tomorrow evening the moon is closer to Spica.

Additionally, Venus is farther from Mars and stepping toward Regulus.

Detailed Daily Note: One hour before sunrise, Saturn is nearly 23° above the southwest horizon.  Retrograding in Capricornus, Saturn is 2.6° to the lower right of θ Cap. Through a binocular spot 19 Capricorni (19 Cap, m = 5.8), 0.2° to the upper right of the Ringed Wonder.  Jupiter is 19.7° of ecliptic longitude to the east (upper left) of Saturn.  Jupiter retrogrades in Aquarius, 2.4° to the upper left of ι Aqr, 4.4° below θ Aqr, and 4.4° to the lower right of σ Aqr.  With an optical assist of a binocular, spot the Jovian Giant between dim 38 Aqr and 42 Aqr.  Fifteen minutes later, Mercury (m = −0.7) – 18° west of the sun – is nearly 5° above the east-northeast horizon and nearly 26° to the lower left of Aldebaran.  The sun is in the sky for 5 minutes less than 15 hours. One hour after sunset, the waxing crescent moon (6.0d, 35%) – over 26° above the west-southwest horizon – is 4.1° to the right of Porrima (γ Vir. m = 3.4).  Farther westward along the ecliptic, brilliant Venus – 29° east of the sun – is nearly 6° up in the west-northwest, 1.5° to the upper left of Mars and 7.3° to the lower right of Regulus.  Saturn rises 55 minutes after sunset, while Venus sets nearly 40 minutes later.  Can you find them in the sky together? Through a telescope, Venus is an evening gibbous that is 87% illuminated and only 11.8” across.  Jupiter rises 109 minutes after sunset.  As midnight approaches, bright Jupiter is over 15° up in the east-southeast, while Saturn is over 21° above the southeastern horizon.

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