Old Moon Meets Saturn At Dawn / Mars Rivals Antares

The moon will direct you to Saturn low in the southeast at dawn Sunday morning. The two will be in conjunction and just 1.5° or three moon diameters apart. The best time to spot the moon and planet will be at the start of dawn or between about 6-6:30 a.m. local time. Stellarium

Saturn’s back! I spotted the ringed one low in the southeastern sky around 6:15 Friday morning. It’s the final runner in a planetary relay race that starts with Jupiter in the south and Mars in the southeast. Saturn takes the baton to the dawn finish line. Because of its low altitude you might not notice the planet without a little help from our friend, the moon. It’s a waning crescent, traditionally called the “old moon” because of it advanced age. On Sunday morning, it’s all of 25 days old and won’t regain its youth until it’s made “new” again on the 15th

Antares shines with a red tint in the heart of the constellation of Scorpius the Scorpion. It’s a huge and comparatively cool red supergiant star in the late stages of its life, on the way to becoming a supernova. Astronomers recently mapped the star’s surface to show heat bubbles rising up from below. ESO

To see all three planets find a place with a good view to the south-southeast. Jupiter’s easiest because it’s the brightest and highest. A fist and a half to the lower left of Jupiter you’ll see two reddish-orange “stars.” The top one is Mars, the bottom Antares. Both are currently the same brightness with Antares at magnitude 1.05 and Mars at 1.06. OK, there’s a hundredth of a magnitude difference between them, but no need to split hairs.

Despite their identical brightness, Antares looked a smidge brighter and more intense to my eye. What do you see? Mars and Antares have always been a tangled relationship because they’re both red and both bright. Iron oxide dust blowing around Mars’ desert landscape is responsible for the planet’s red color, while Antares is a large, cool star. Cool stars are redder than hot ones just like a stove heating coil looks deep red on medium heat compared to bright orange when the heat is set to high.

Mars this weekend around 6:30 a.m. Central time. Meridian / Claude Duplessis

Even the name Antares alludes to Mars. It comes from the ancient Greek “anti-Ares” or like Ares. Ares was the Greek name for the planet. Tomorrow morning, they’ll be just 5° apart. If the air is still and steady, Mars will show a tiny gibbous shape and several dark markings on its surface in a modest telescope magnifying around 100-150x. The most prominent feature at the moment — at least for observers in the Americas — is Mare Acidalium (Acidalium Sea) a dark finger extending south from the north polar cap. It’s laced with gullies, canyons and may trace the shoreline of an ancient ocean.

To find Saturn, look two and half fists to the lower left of Mars. With the moon as your guide on Sunday, the task with be simple. Just find the moon and Saturn sits directly below it. At low altitude, Saturn’s rings usually lack crispness and may appear to ripple in the turbulent air when viewed through a telescope, but take a look anyway and give the planet an early welcome. Come summer, come the bugs, all three planets will rule the evening sky.