This evening – August 23, 2018 – as soon as darkness falls, enjoy the beautiful presence of the moon and Mars in your southeast sky. They can be viewed from all over the world, except at the far-northern Arctic latitudes. These two worlds – the moon and Mars – rank as the brightest and third-brightest celestial luminaries to light up the nighttime sky, respectively. So you should have little or no trouble spotting this august couple before nightfall, or at evening dusk.
Best of all, the moon and Mars stay out for most of the night. From around the world, the stately couple climbs highest up for the night at roughly 10 p.m. local time (11 p.m. local daylight-saving time) and then set in the southwest in the wee hours before dawn. If you want to know more specifically when the moon and Mars transit – or climb highest up for the night – and then set, click on this US Naval Observatory page.
If you haven’t seen Mars yet – or even if you have – let the moon guide your eye to Mars tonight. Be sure to get an eyeful of Mars while it’s still in its moment of glory. Earth, in its faster orbit around the sun, is leaving Mars farther and farther behind; and as a consequence, Mars will slowly but surely dim in the months ahead. One month from now, in September, Mars will be about half as bright as it is now; and one month from now, in October, Mars will be about one quarter of its present brightness.
Despite this rapid decline in brilliance, we’re happy to report that Mars will still be as bright as a 1st-magnitude star by the year’s end. Some four months from now, in December 2018, Mars’ brightness will be about the same as that of the planet Saturn at present (August 2018). However, Saturn’s change in brightness is not that dramatic. In fact, one year from now – in August 2019 – Saturn will be virtually the same brightness that it is now, yet Mars will be about 40 times fainter than it is now.
By the way, look into your southwestern sky at dusk for the planets Venus and Jupiter, the second-brightest and fourth-brightest heavenly bodies to adorn the nighttime sky, respectively. Don’t tarry, though, when seeking out these brilliant worlds – especially Venus, which sets around nightfall at mid-northern latitudes.
Tonight – August 23, 2018 – the bright waxing gibbous moon pairs up with the brilliant red planet Mars, and the spectacular twosome lights up the nighttime from dusk until the wee hours of the morning.