Earth is zooming toward the planet Mars for a close opposition in mid-October. When at its closest, Mars will shine brighter than the brilliant planet Jupiter, and with its rusty-red color, it will be a spectacular beacon in our autumn sky. Both Jupiter and Saturn will be shining brightly nearby, only three months after their own oppositions.

It takes an average of 780 days for the faster Earth to gain a lap on Mars and pass between it and the sun for an opposition, so, close approaches to Mars can only happen once every two years. Also, because of Mars’ lopsided orbit, some oppositions are closer and more favorable than others. Under the most favorable conditions, Mars can come as close as 34.6 million miles, as it did in 2003.

When Mars reaches opposition Oct. 13, it will be 39 million miles from Earth, a very favorable opposition. The closest approach to Mars will happen a week earlier, on Tuesday, when Mars will be 38.6 million miles from Earth. Mars won’t be this close to Earth again until Sept. 15, 2035.

This year’s opposition doesn’t put Earth and Mars quite as close together as they were in 2018, but Mars will appear much higher in our sky and hindered less by atmospheric distortion. Mars will be glowing prominently in the constellation of Pisces, the Fish. Look for it near the horizon in the eastern sky as darkness falls, then rising highest in the southern sky around midnight before appearing on the western horizon at dawn.

Through a medium-sized telescope, Mars will look like a flaming red ball, but look more closely and you might be able to make out some of its dark-colored deserts and maybe even its snowy white south polar ice cap. Glimpsing these Martian features through your own backyard telescope is a thrill that doesn’t present itself very often, so make the most of it. The best time for telescopic observing is around midnight, when Mars is highest in the sky.

October opens with a spectacular full Harvest Moon on the first day of the month this year. Because full moons happen every 29.5 days, that leaves enough time to squeeze a second full moon into October on Halloween night.

Traditionally, the second full moon in any calendar month is called a blue moon. Although it is unusual, it isn’t rare. Blue moons like this happen about every 2.7 years on average. A blue moon on Halloween, however, is rare, happening only three or four times per century. The last time that it happened for all four time zones in the contiguous U.S. was in 1944. 

Jimmy Westlake is the former fulltime professor of physical sciences at Colorado Mountain College Steamboat Springs and former director of the Rollins Planetarium at Young Harris College. His “Celestial News” column appears monthly in the Steamboat Pilot & Today. Check out Westlake’s astrophotography website at jwestlake.com.