As far as I’m concerned, any October is primetime for great stargazing, but this October of 2020 is a bonanza of celestial happenings! The headliner is Mars, which will be the closest it’s been to Earth in over two years. It won’t be this close again until 2035.
This Tuesday, Mars and Earth will be less than 38.6 million miles away from each other. Every two years and two months, Earth and Mars catch up with each other. The Earth is a line between Mars and the sun. This is called opposition. Both planets are nearly at their minimum distance from each other. The actual opposition date for Mars is on Oct. 13. If the Earth and Mars orbited the sun in perfect circles in the same exact plane, Earth and Mars would be at their minimum separation on Oct. 13 and not Oct. 6. For that same reason, not all opposition distances are the same. Some are much closer than others, as it in 2020.
At opposition, Mars and the sun are on opposite sides of the sky. Just like a full moon, Mars rises at sunset and sets at sunrise so it’s available all night long. It’s by far the brightest star-like object in the evening sky in October, and you’ll also quickly see why it’s called the red planet with its reddish-orange glow.
Mars is a prime target for even small telescopes in October. It really helps to let Mars get as high in the sky so it rises above the thicker layer of Earth’s blurring atmosphere near the horizon. That means staying up as late as you can to observe Mars. It’s also important to take long continuous looks through your telescope so your eye can adjust to the light level inside the scope. I’ll have much on Mars next week in Skywatch.
Meanwhile, Jupiter and Saturn, the giants of the solar system, are still in a close celestial hug. They start evenings in the low south to southwest sky and set between 10 and 11 p.m. The giant planets are not as close to Earth as they were in the summer, but they’re still the brightest star-like objects in that part of the sky. Jupiter is the brighter of the two. While they are not as close to the Earth anymore, they are drawing closer to each other in the sky. This month, Jupiter and Saturn will be less than 10 degrees apart, close enough that you can fit both planets in the same field of view of a pair of binoculars. As autumn continues they’ll get even closer. On Dec. 21, the first day of winter, they’ll look like they’re almost “touching,” only a tenth of a degree apart! That’s the closest these planets have been to each other in the sky since 1623 AD.
The Moon is also a huge headliner in the October skies. We have two full moons this month. On Oct. 1, we had a full harvest moon, and on Oct. 31, we’ll have another full moon! According to the modern-day definition that makes it a “Blue Moon,” the second full moon of the month, just in time for Halloween!
Even without all of the special celestial events going on, October night skies are pretty special. Early in the evening there are still many summer constellations in the western half of the sky like Bootes and Cygnus the Swan, while in the eastern sky, great autumn constellations like Pegasus the Winged Horse and Perseus are on the rise. Late in the month, the wonderful Pleiades star cluster starts showing up in the early evening eastern skies. Appropriately, the Pleiades are also known as the Halloween cluster.
October skies are exceptionally wonderful this year!
Mike Lynch is an amateur astronomer and retired broadcast meteorologist for WCCO Radio in Minneapolis/St. Paul. He is also the author of “Stars: a Month by Month Tour of the Constellations,” published by Adventure Publications and available at bookstores and adventurepublications.net. Mike is also available for private star parties. You can contact him at firstname.lastname@example.org.
UPCOMING MIKE LYNCH MINNESOTA/WISCONSIN STARWATCH
- Monday, Oct. 5, 7-8:30 p.m., Lonsdale Elementary School in Lonsdale. Reservations required. For more information call Community Education, 507-364-8107 or tricity.cr3.rschooltoday.com/public/home/
- Tuesday, Oct. 6, 7:15 to 8:45 p.m., Northfield Middle School in Northfield. For more information and reservations call 507-664-3650 or nfld.k12.mn.us/communityservices/
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