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Moon, Saturn and Antares at nightfall August 21

2015-aug-21-antares-saturn-moon-night-sky-chart

Tonight for August 21, 2015

Watch for the rather wide waxing crescent moon, the planet Saturn and the star Antares to adorn the southwest sky as darkness falls. Take a stroll with a loved one, or family and friends, to see all these celestial luminaries lighting up starry heavens first thing at nightfall.

The lunar glare may somewhat obstruct the view of these Saturn and Antares tonight. So if you have binoculars, use them to get a better view. Antares exhibits a ruddy color whereas Saturn appears golden.

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Because the Earth spins from west-to-east upon its rotational axis, it causes the moon, Saturn and Antares to swing in the opposite direction – westward – during the evening hours. Relative to Saturn and Antares, however, the moon actually moves eastward, toward Saturn and Antares. The dark side of the waxing moon always points in the direction that the moon travels in front of the constellations of the Zodiac. Relative to the backdrop stars of the Zodiac, the moon travels eastward at about one-half degree per hour, or about 13o daily. The chart below shows the moon’s change of position for the next few evenings.

The moon moves eastward relative to the background stars and planets of the Zodiac. The dark side of the waxing moon  points eastward - in the moon's direction of of travel. The green line depicts the ecliptic - Earth's orbital plane projected onto the constellations of the Zodiac.

The moon moves eastward relative to the background stars and planets of the Zodiac. The dark side of the waxing moon points eastward – in the moon’s direction of of travel. The green line depicts the ecliptic – Earth’s orbital plane projected onto the constellations of the Zodiac.

Bottom line: The moon and two bright celestial luminaries – Saturn and Antares – adorn the southwest sky as darkness falls on August 21.

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