Photos of Mercury's Transit Across Sun

Mercury is visible as it transits across the sun on Monday, a rare celestial event that only occurs about 13 times a century, according to NASA.

Photos taken Monday morning show a tiny black shadow on the left side of the sun. The planet began its journey around 7:35 a.m. EST, Space.com reported, and will continue until 1:04 p.m. The transit is visible from most places on Earth, including the Americas, the Atlantic and Pacific Oceans, New Zealand, Europe, Africa and western Asia.

(MORE: Don't Miss Rare Mercury Event This Monday)

While Mercury is too small to see with the naked eye, a telescope or binoculars with solar protection can help.

Stargazers won't witness an event like this until 2032, and in the U.S., until 2049.