In this series of old family photos, follow the trajectory ... that would soon be known to all the world as Pluto. My father worked for the Lowell Observatory for the next 15 years.

For ticket and weekend event information, head to the I Heart Pluto Festival website as well as the Lowell Observatory website. Need a place to stay in Flagstaff during the I Heart Pluto Festival ...

Suddenly, in photos taken six days apart ... And so on May 1, Lowell Observatory announced that Planet X would be named Pluto. But with its peculiar, tilted orbit and confoundingly small size ...

Ever since NASA's New Horizons sent back the first-ever photos of Pluto ... from north to south. Pluto was discovered in 1930 by Clyde Tombaugh while he worked at Lowell Observatory in Flagship ...

At the Lowell Observatory, visitors can conjure their inner astronomer by peering through world-class telescopes and sitting in on lectures on topics like black holes and the history of Pluto.

In 1930, the Lowell Observatory announced the discovery of a ninth planet at the end of the solar system: Pluto. Start the day smarter. Get all the news you need in your inbox each morning.