Mars, Jupiter and Saturn have been a delight. Every dawn brings a new arrangement to light. A week ago, Mars hammocked between Saturn and Jupiter. Tomorrow morning it will slide less than 1° below Saturn in a truly eye-catching conjunction. Being closer to the Earth Mars moves considerably faster than the two outer planets. The same way we zip in and out of a grocery store in hopes of minimizing our potential exposure to the coronavirus, Mars pays Jupiter and Saturn quick visits before heading off on its own to the east. Saturn and Jupiter are also moving eastward as they orbit the sun but much more slowly. They’re also much farther away, which makes them look even more sluggish.
I included the constellation boundaries on the map (above) to show you that Jupiter currently shines in Sagittarius the archer while Mars and Saturn have crossed the border into Capricornus the sea goat. Each of the 88 constellations has set boundaries just like countries or states. This is to help both professional and amateur astronomers know where things are in the sky whether that be a planet or a newly discovered comet.
Jupiter is the brightest of the trio while Mars and Saturn are fainter and near-equals. Can you tell which one is brighter? Answer: Saturn by just 1/10 of a magnitude! Being so close it will be fun to compare each planet’s color. Mars should be an obvious red-orange, a hue caused by vast quantities of iron oxide (rust) in its soil. Saturn looks pale yellow from quantities of sulfur in its atmosphere.
Mars will continue to outpace the outer planets as it plows deeper into Capricornus. Click here for Tom Ruen’s 50-day animation of the planets’ paths. If you broaden your gaze while you’re out tomorrow morning you can connect the planetary trio with the Summer Triangle to form a gigantic “Y” in the sky. The bright stars Vega, Deneb and Altair lie at the apices of the triangle and remind us that summer is on its way.