July 25, 2018: Friday, July 27th, is a big night for astronomy. Three reasons: First, Mars will be at opposition–directly opposite the sun and making a 15-year close approach to Earth. Second, Mars and the full Moon will be in conjunction–less than 10 degrees apart. Third, the Moon will pass through the shadow of Earth, producing the longest lunar eclipse in a century.
Graphic artist Larry Koehn of ShadowandSubstance.com created this montage of the eclipse:
An animation of the eclipse may be found here.
Almost everyone on Earth (except North Americans) can see the eclipse as the sunset-colored shadow of our planet swallows the Moon for almost 2 hours. During totality, the Moon will turn almost the same red color as Mars right beside it–an incredible sight.
Because Mars is opposite the sun, it will rise at sunset and stay up all night long. The best time to look is around midnight when the Moon-Mars pair will be at their highest in the sky. The Red Planet will have no trouble being seen through the glare of the full Moon because Mars itself is so luminous–almost three times brighter than Sirius, the brightest star in the sky.
People in North America will not be able to see the eclipse. The shadow play happens mostly on the opposite side of the world. They can, however, witness the conjunction. Swinging a backyard telescope between the Moon and Mars in quick succession will reveal the dusty-red martian disk alongside lunar mountains and craters. It’s a special night. Enjoy the show!