Enlarge / The Y-shaped Navy Precision Optical Interferometer in northern Arizona can function like a telescope with a mirror 400 meters wide. (credit: Google Maps)

If Lowell Observatory’s Gerard van Belle gets his way, someday soon you’ll be watching an exoplanet cross the face of its star, hundreds of light-years from the Earth. He can’t show you that right now, but he should be able to when the new mirrors are installed at the Navy Precision Optical Interferometer in northern Arizona. They’re arriving now, and should soon start collecting starlight—and making it the highest-resolution optical telescope in the world.

Van Belle recently showed Ars around the gigantic instrument, which bears almost no resemblance to what a non-astronomer pictures when they hear the word “telescope.” There are a couple of more traditional telescopes in dome-topped silos on site, including one built in 1920s in Ohio, where it spent the first few decades of its life.

Going big

The best way to improve imagery on these traditional scopes is to increase the diameter of the mirror catching light. But this has its limits—perfect mirrors can only be built so large.