Tonight

Young moon, Venus and Mars conjunction

Young moon sweeps by Venus, Mars and Regulus in the July evening sky.

Catch the newborn baby crescent

Find an unobstructed horizon in the direction of sunset. Then, as dusk gives way to darkness on July 11 and 12, look westward after sunset to catch young moon pairing up with the dazzling planet Venus. With binoculars, see if you can spot the much fainter planet Mars next to Venus in a single binocular field of view. If the whisker-thin crescent eludes your detection on July 11, try again on July 12. You won’t want to miss the beautiful evening presence of the moon and Venus!

Day by day, a wider yet still slender waxing crescent will appear higher up at sunset, and will stay our later after dark. On July 13, 14 and 15, 2021, the illuminated side of the moon serves as your arrow in the sky, pointing downward to the star Regulus and the planet Venus. Regulus, though a respectably bright star, pales in contrast to Venus, with Venus shining more than 100 times brighter than Regulus.

A barely visible crescent moon set against bright twilight.
View larger. | Don’t expect a very young moon to pop out at you, brightly and noticeably. It’ll be a very subtle sight, the most fragile of crescents, set low in the sky just after sunset, against bright twilight. This very young moon was captured by our friend Susan Gies Jensen on February 10, 2013, in Odessa, Washington. Beautiful job, Susan! Thank you.

From most places worldwide – given clear skies and an unobstructed horizon – you should have a good chance of seeing both the newborn baby crescent and Venus some 45 minutes (or less) after sunset on July 11. After all, the moon and Venus rank as the second-brightest and third-brightest celestial bodies to light up the sky, respectively, after the sun. But don’t tarry! Venus (and Mars) will follow the sun beneath the horizon before nightfall at mid-northern latitudes and far-northern latitudes; in contrast, Venus and Mars will set after nightfall in Southern Hemisphere.

When is nightfall?

We give the approximate time of nightfall (end of evening twilight), and Venus’ setting time at various latitudes (presuming an absolutely level horizon):

40 degrees north latitude
Venus sets: 1 hour and 35 minutes after sunset
Nightfall: 2 hours after sunset

Equator (0 degrees latitude)
Nightfall: 1 hour and 15 minutes after sunset
Venus sets: nearly 2 hours after sunset

35 degrees south latitude
Nightfall: 1 hour and 30 minutes after sunset
Venus sets: 2 hours and 10 minutes after sunset

Find out Venus’ specific setting time in your sky at Old Farmer’s Almanac or TimeandDate.com

We should mention that the setting time of the moon is variable, depending upon longitude as well. Find out the specific moonset time in your sky via TimeandDate.com.

Venus and Mars in conjunction on July 13

We did not mention Mars’ setting time because Mars and Venus set at nearly the same time for the next several days. With Venus outshining Mars by about 200 times, you will probably need binoculars to see Mars in the same binocular field with Venus. Depending on where you live worldwide, Venus and Mars will be closest together in the evening sky on July 12 or July 13. At conjunction, Venus will pass 1/2 degree north of Mars on July 13, 2021, at about 7 UTC. (For reference, the moon’s diameter spans about 1/2 degree of sky.)

After the moon goes by Venus (and Mars), it’ll lap Regulus, the constellation Leo’s one and only 1st-magnitude star, about a day later. Pay attention to this “fixed” star of the zodiac throughout the rest of July 2021, to note the changing positions of Venus and Mars.

Venus and Mars are both heading for Regulus as we speak. Venus will have a conjunction with Regulus on July 21, 2021, passing 1.2 degrees north of this star. Then, on July 29, 2021, Mars will rendezvous with Regulus, sweeping 0.7 degrees north of Leo’s brightest star.

In the meantime, be sure to get an eyeful of the young moon pairing up with Venus (and Mars) on July 11 and 12. Then, on the following evenings – July 13, 14 and 15 – use the moon’s illuminated side as your pointer to Regulus and Venus.

A fine example of earthshine on a waning crescent moon, as the moon shone near Venus in the morning sky on June 2, 2019. The lunar terminator – the line dividing the lunar day from the lunar night – shows you where it’s sunset on the old, waning crescent moon. Photo by Jenny Disimon.

What is earthshine

Also note – with the eye alone or an optical aid – the soft glow of earthshine adorning the dark or nighttime side of the moon. Earthshine is twice-reflected sunlight, with the Earth reflecting sunlight to the moon, and the moon, in turn, reflecting sunlight back to Earth. The lunar terminator – the line dividing the lunar day from the lunar night – shows you where it’s sunrise on the young, waxing crescent moon.

Make it a family affair and bring along the kids. Their young eyes may catch the young moon and Venus popping out at evening dusk before yours do.

Posted 
July 11, 2021
 in 
Tonight

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