Ground-Based Observatories
The Owens Valley Radio Observatory (OVRO), near Bishop, California, is home to a number of Caltech-operated radio telescopes.
Caltech's Palomar Observatory is home to the venerable Hale 200-inch Telescope, as well as the 60-inch instrument, the 48-inch Samuel Oschin Telescope, and an 18-inch Schmidt camera.
Keck Observatory is a joint effort of Caltech and the University of California, consisting of twin 10-meter telescopes, Keck I and Keck II.
Space-Based Missions
The Nuclear Spectroscopic Telescope Array (NuSTAR) mission is a high energy X-ray orbital mission whose science operations center is located at Caltech.