Large Binocular Telescope (LBT)

Located at Mt. Graham International Observatory, the LBT is currently the largest telescope in the world. The Large Binocular Telescope is used by astronomers across the globe, was recently used to capture the first images of a planet in the making.

About the Large Binocular Telescope

The Large Binocular Telescope (LBT) is made up of a set of two, identical 8.4-meter (or roughly 28 feet) mirrors, side by side and operating on a common, steerable mount. The telescope is 600 tons of steel and glass and, today, is the largest in the world.

Located in southeastern Arizona’s Pinaleño Mountains, the LBT stands at just under 11,000 feet tall. It operates as part of the Mount Graham International Observatory.


The Univeristy of Arizona's Large Binocular telescope snow on Mt Graham International Observatory
The Univeristy of Arizona's Large Binocular telescope snow on Mt Graham International Observatory

The LBT has a history that spans over three decades, and it begins with the work of Roger Angel, University of Arizona professor of astronomy. In the early 1980s, Angel was developing technology to produce large, lightweight honeycomb mirrors that are now produced at the UA’s Richard F. Caris Mirror Lab.

Not long after, three of the LBT’s current partners—the UA, Ohio State University, and the Arcetri Observatory in Italy—began collaborating on what was then being called the “Columbus Telescope.” They aimed to design and construct a 11.3-meter telescope by the 500thanniversary of Christopher Columbus’ arrival in the New World. Their initial design relied on Angel’s new mirror technology.

Over the following decade, the consortium of university and institutional collaborators shifted and, in 1993, the name changed from “Columbus” to “Large Binocular.” Construction of the LBT began in 1996.  

At the Mirror Lab, years of development eventually culminated with the casting of the first 8.4-meter mirror for LBT which started in 1997. The telescope structure was completed in Italy and shipped to Arizona in the summer of 2002.

Since then, the LBT has been used in a myriad of astronomical discoveries, including the first images of a planet in the making captured by UA researchers in 2015