NIGHT SKY: Mars, Saturn and Antares line up in the August twilight
Step outside as the stars come out, look southwest, and you’ll see an eye-catching pattern
Mars, Saturn and Antares make for an excellent showing. Image Credit: Peterborough Astronomical Society
Step outside as the stars come out, look southwest, and you’ll see an eye-catching pattern. For the next few days and between 17 and 22 August, bright orange Mars shines to the right of Saturn and the reddish supergiant star Antares. The three form a tall triangle that changes every night.
Mars is moving leftward on its way toward passing between the other two. On 23 and 24 August, the triangle will shrink right down to a nearly vertical line of three shining points.
After that, Mars will continue leftward and the triangle will widen again, now pointing in the opposite direction.
Not that the three have anything to do with each other. Mars is the nearest of them, 7 light minutes from Earth (79 million miles). Saturn is almost a dozen times farther away: 82 light minutes (914 million miles). Antares, the lowest of the three in the sky, is about 550 light years in the background, or 3.3 quadrillion miles into deep space.
Fainter stars of the constellation Scorpius glimmer in the area too.
Notice that, being a star, Antares is the only one of the bright three that twinkles. That’s not the star’s own doing; twinkling is caused by the slight heat waves that are always rippling through in Earth’s atmosphere, mostly just a few miles from your eyes. Planets appear larger from our viewpoint, so the separate shimmers of each point on a planet’s face generally average out to a steady glow.
Meanwhile, the two very brightest planets – Venus and Jupiter – are going through antics of their own. They’re way down low, due west after sunset. Look for them close to the horizon, somewhat left of where the Sun went down, 20 or 30 minutes after sunset. If you have a very low view and clear air, you’ll see that Venus and Jupiter are drawing closer together every evening. Venus is the lower one. If the air is hazy, binoculars will help.
By 24 August, Venus and Jupiter will appear separated by just two finger-widths at arm’s length. On the 26 August they’ll be less than one finger apart. Then on 27 August, they’ll have such a close conjunction that you may need binoculars to see that they’re two objects, not one.
Again, looks are deceiving. The two planets merely happen to be along our same line of sight. Venus on 27 August is 13 light minutes from Earth (144 million miles), while Jupiter is four times farther: 53 light minutes away, or 592 million miles.
Get stargazing tips, telescope and kit reviews with All About Space – available every month for just £4.99. Alternatively you can subscribe here for a fraction of the price!