The Leonid meteor shower is expected to reach its peak Tuesday evening, and continue into Wednesday morning. According to the American Meteor Society and International Meteor Organization, approximately 15 meteors should be visible per hour, at the shower’s peak.

The Washington Post reports that meteors should be visible after 11:00 p.m. The moon is presently in a crescent phase, allowing greater visibility to stargazers. As long as clouds clear the skies, and watchers find a place away from light pollution, the meteor shower should be visible until the early hours of Wednesday morning.

Meteor showers are the result of small pieces of a comet breaking off and colliding with Earth’s path. The small fragments burn up in Earth’s atmosphere, emitting light, or “shooting stars.” The Leonid meteors come from Comet Tempel-Tuttle, discovered in both Germany and America around 1866. The comet is a periodic one, meaning its path crosses with Earth on semi-regular intervals. In the case of Comet Tempel-Tuttle, it usually returns every 33 years. The comet last passed in 1998, and is expected to return again in 2031.

In 1966, the Leonids produced a meteor shower that had thousands of visible meteors per hour, at its peak. The most active recorded meteor shower recorded in history took place in 1833. That storm had at least 200,000 visible meteors per hour, and peaked for around four hours.