text: One of these objects is nicknamed SALT and uses 91 hexagonal segments.
full_question: One of these objects is nicknamed SALT and uses 91 hexagonal segments. Two of these devices named for W. M. Keck are on altazimuth [al-TAZ-uh-muth] mounts. One of these objects named for Subrahmanyan Chandrasekhar [soo-brah-MAHN-yahn shahn-druh-SAY-kar] detected an X-ray burst from Sagittarius A* [“a-star”]. The Very Large Array consists of 27 of these devices that are currently performing a full scan of the sky. Another one of these devices is planned for launch in 2019 and is named for James Webb. Name these devices that may use lenses or mirrors to detect electromagnetic radiation coming from space.
first_sentence: One of these objects is nicknamed SALT and uses 91 hexagonal segments.