Venus Meets Mars In A Cosmic Tryst With A Twist: What You Can See In The Night Sky This Week

Venus and Mars in close conjunction in the dawn sky on October 5, 2017 Venus is the brightest object; Mars is below it; while the star above Venus is 4th magnitude Sigma Leonis The foreground is illuminated by light from the setting Full Moon in the west This is a single 1-second exposure with the 135mm lens at f/2 and Canon 60Da at ISO 800 Compared to the earlier shot with the lens stopped down, Venus did not show diffraction spikes as the lens was wide open at f/2 So I added the diffraction spikes with the Astronomy Tools action set The sky here is also more coloured from the dawn twilight. (Photo by: VW Pics/Universal Images Group via Getty Images) Universal Images Group via Getty Images

Each Monday I pick out the northern hemisphere’s celestial highlights (mid-northern latitudes) for the week ahead, but be sure to check my main feed for more in-depth articles on stargazing, astronomy, eclipses and more. 

What To Watch For In The Night Sky This Week: July 12-18, 2021

This week sees Venus meet Mars in the first part of a “triple conjunction” that will see the two appear to meet three times between now and early 2022. Or so it will seem.

Planetary “conjunctions” like this are, of course, an illusion since they’re millions of miles apart. All that changes is Earth’s point of view of the Solar System as it zips around the Sun. 

This week also sees a delicate crescent Moon rising, gracefully passing the planetary duo early in the week before it waxes to its First Quarter phase. Here’s exactly what you need to know about sky-watching this week: 

When to see Mars and Venus closest together #1: looking west at 9pm, Monday, July 12, 2021. Stellarium

Monday, July 12, 2021: Venus, Mars and the Moon in a close conjunction

Tonight the planets Venus and Mars will be 0.5º apart low in the west-northwest sky at dusk while just above will be an 8.4%-lit waxing crescent Moon.

If you struggle to see Mars then use binoculars and look to the lower-left of Venus, which will appear about 200 times brighter!

When to see Mars and Venus closest together #2: looking west at 9pm, Tuesday, July 13, 2021. Stellarium

Tuesday, July 13, 2021: Venus and Mars in a close conjunction

Look to the west-northwest sky just after sunset tonight and you’ll get another chance to see Mars and Venus about 0.5º from each other, only this time Mars will be just below Venus. A 16%-lit crescent Moon will linger high in the southwest.

First Quarter Moon Sergei Malgavko/TASS

Saturday, July 17, 2021: First Quarter Moon

Today is First Quarter Moon, when our satellite appears to be 50% illuminated, rising in the east around midday and setting in the west around midnight. 

Night sky with enhanced Constellation of Cygnus, asterism of The Northern Cross, and Summer Triangle with Vega, Deneb and Alstair, the Milky Way is the background getty

Asterism of the week: the Northern Cross

Unlike constellations, 88 of which are officially designated by the International Astronomical Union (IAU), an asterism is simply an informal shape of stars in the night sky. One of the most famous in summer in the northern hemisphere is the Northern Cross, which is essentially the upside-down version of the constellation of Cygnus, the Swan. The top of the cross is marked by Deneb—a blue-white supergiant star 2,600 light-years distant—and the bottom by the blue and red Albireo double star. 

Times and dates given apply to mid-northern latitudes. For the most accurate location-specific information consult online planetariums like Stellarium and The Sky Live. Check planet-rise/planet-set, sunrise/sunset and moonrise/moonset times for where you are.

Wishing you clear skies and wide eyes.