The 200-inch (5.1 m) Hale Telescope (f/3.3) was the world's largest effective telescope for 45 years (1948-1993). It is still a workhorse of modern astronomy. It is used nightly for a wide range of astronomical studies. On average the weather allows for at least some data collection about 290 nights a year.

The Palomar Observatory is located in north San Diego County, California. It is a world-class center of astronomical research that is owned and operated by the California Institute of Technology. The observatory is home to five telescopes that are nightly used for a wide variety of astronomical research programs. The research is conducted by Caltech's faculty, post-doctoral fellows and students, and by researchers at Caltech's collaborating institutions.