These observatories are used by Center members for many observational and engineering projects. NRAO and NAIC telescopes are used in NANOGrav's search for low-frequency gravitational waves and LIGO is used by Center members searching for high-frequency waves.
The National Radio Astronomy Observatory (NRAO) operates the Green Bank Telescope (GBT), in Green Bank, WV, the largest steerable telescope in the world.nrao.edu
The National Astronomy and Ionospheric Center (NAIC) operates the Arecibo Observatory in Puerto Rico, the largest telescope in the world.naic.edu
Advanced LIGO consists of two separated installations, one in Hanford, WA and the other in Livingston, LA. They operate in unison as a single observatory.advancedligo.mit.edu