On Sunday night, Earthlings will get a rare opportunity to see Mercury just above the horizon after sunset. The viewing opportunity is due to Mercury being at its greatest elongation from its neighbor the Sun, moving to its farthest point of 27 degrees on July 30. Because it will be Mercury’s greatest eastern elongation, expect to see the smallest of our solar system’s planets east of the sunset — aka low in the western sky after sunset.
According to EarthSky, your best bet is to look for the innermost planet around 45 minutes after sunset.
A few other things to keep in mind to help you get the best view:
- Good weather conditions: a rare sighting of far away Mercury will be considerably easier with a clear sky.
- Follow the Moon and Jupiter: The two are in line at this time of year, and Mercury will join them as they rise. Jupiter is experiencing good visibility in the early evening, so set your sights on these two bright points to find Mercury.
- An unobstructed horizon: your view of Mercury after sunset — although longer than usual because of the planet’s rare distance from the Sun — will be close to the horizon, as Mercury’s wacky orbit keeps it close to our star.
Unfortunately, the Northern Hemisphere will be getting the short end of the stick, visibility-wise. Northern-located sky-watchers will get less than an hour and a half to see Mercury with the help of the dark. According to The Old Farmer’s Almanac, in New York, for instance, Mercury will set by 9:18 p.m. To the north in Juneau, Alaska, Mercury will be visible until 9:46 p.m., an hour and 20 minutes after the Sun. In Southern Hemisphere — like Tasmania for example — Mercury will set two hours and 15 minutes after the sun.
It’s probably unnecessary to point out, but don’t try to find Mercury while the Sun is still above the horizon, as exposing your eyes to our star is incredibly unsafe.