Mars shows off in the southeastern sky
Mars is a mere 38.6 million miles from Earth this week, the Red Planet's closest approach in two years.
It’s been building since this past summer and culminates this month — the great Mars show of 2022. Even before evening twilight ends, Mars will be on the rise in the low eastern sky. It will certainly be the brightest star-like object in that part of the heavens, sporting an orange-red glow. Earth and Mars are at their closest approach to each other in over two years. This week Mars is only a little more than 38.6 million miles from Earth.
Mars and Earth are in what astronomers call opposition this week. That’s when Earth lies in a line between the sun and Mars, putting Mars and Earth at minimum separation. It also makes Mars available all night long, rising at sunset and setting at sunrise. It takes Earth 365.25 days to make one complete orbit around the sun, while it takes Mars 687 days. Because of that, Mars and Earth go into opposition about every two years. In opposition, Earth lies roughly in a line between Mars and the sun.
Now is a wonderful time to check out Mars, even with a small to moderate telescope. Mars is the only planet in our solar system where you can actually see the surface. With other planets like Jupiter, Saturn, and Venus, all you see are cloud tops. I certainly don’t want to oversell what you’ll see on Mars though. It’s still only a 4,000-mile-wide planet roughly 38 million miles away. Even with higher magnification, Mars will not fill up the field of your telescope eyepiece.
To get your best telescope views, you’ll want to allow Mars to get high enough above the horizon and thick layer of blurring atmosphere. If you wait to aim your scope at Mars until after 8 pm, you should be in pretty good shape. It’s essential to be patient and comfortable while looking through your scope because you want to take long, continuous views of Mars, at least five to 10 minutes at a time. That gives your eye a chance to adjust to the light level in the eyepiece field and will take advantage of patches of less turbulent and more transparent air passing by.
Depending on how good the viewing is, you should be able to see the south polar cap on Mars, made up mostly of frozen carbon dioxide. If your telescope shows you a reverse image, as most do, the southern polar cap will be toward the upper limb or disk of the planet. With larger telescopes, and even small to moderate ones, you may see dark patches on Mars. These are mainly rocky fields, plains, and vast canyons on the surface. There‘s even a giant dormant volcano called Olympus Mons. Since Mars rotates on its axis every 24 hours and 37 minutes, a little slower than our Earth, you’ll see changing patterns of dark blotches from night to night and even over several hours of observation.
Sky and Telescope Magazine has a great tool available on their website, skyandtelecope.org . It’s called the Mars Profiler, and with it you can know what surface features on Mars are visible at any time on Earth. It’s great, and I hope you get a chance to use it.
Here’s another tip for using your telescope on Mars or any other object in the night sky. Make sure you let your telescope and any eyepieces you’ll be using sit outside for a good half hour to an hour, so all of the glass and mirrors can adapt to the outside temperature. It really makes a difference.
Enjoy the great holiday Mars invasion.
Mike Lynch is an amateur astronomer and professional broadcast meteorologist for WCCO Radio in Minneapolis/St. Paul and is author of the book, “Stars, a Month by Month Tour of the Constellations” published by Adventure Publications. Send questions to firstname.lastname@example.org .
The Rochester Astronomy Club welcomes new members and puts on public star parties. Their website is rochesterskies.org .