A mountain-size space rock will sail past Earth on Monday, offering stargazers a close look at an interplanetary pinball. Luckily, NASA says there is no risk of collision, but it will be a rare astronomically close encounter that backyard telescope owners can watch.

The large asteroid, called 2004 BL86, measures about a third of a mile (half a kilometer) across. It will make its closest approach to Earth on January 26, coming within only 745,000 miles (1.2 million kilometers) from our planet—about three times the distance separating the Earth and the moon.

While there have been many asteroids that have barnstormed Earth much closer, this will be the largest one to come that close until 2027, when a slightly smaller