Mercury's big move on mercredi

"Usually, you expect to see planets at night. But in broad daylight on Wednesday, November 8th [sunrise on Nov. 9 in Korea], the planet Mercury will cross the face of the Sun.

"It will be visible in silhouette through a telescope with a safe solar filter placed securely over the front. Mercury will transit the Sun for about five hours, looking like a tiny round sunspot creeping westward across the enormous surface of our home star.

Transits of Mercury don't happen very often. The last was on May 7, 2003, and the next doesn't come until May 9, 2016.

"Well-prepared observers will see Mercury edge onto the Sun's face around 2:12 p.m. EST (11:12 a.m. PST). Watchers in western North America can see the entire transit, which ends when Mercury slips off the Sun's edge at 4:10 p.m. Pacific time. Farther east, the Sun will set while the transit is still in progress.

"To see the event, you'll have to be Sun-safe! You can burn a permanent blind spot in your eye's retina by trying to observe the Sun without proper protection -- and a telescope makes the danger more intense. You'll need a safe solar filter designed to go over the front of your telescope.

"Alternatively, you can project the Sun's image out of the eyepiece of a telescope or binoculars onto a white surface a foot or two away; turn the focus knob to get a sharp image of the Sun on the card. For details and illustrations, please see "How to Watch a Partial Solar Eclipse Safely."