× 0. Palomar Observatory
M. Visitor Center (Museum)
H. Hale Dome

Welcome to Palomar Observatory

Palomar Observatory, located atop Palomar Mountain in north San Diego County, California, is a center of astronomical research owned and operated by Caltech. The Observatory is home to three active research telescopes: the 200-inch (5.1-meter) Hale Telescope, the 48-inch (1.2-meter) Samuel Oschin Telescope, and the 60-inch (1.5-meter) telescope. Research at Palomar Observatory is pursued by a broad community of astronomers from Caltech and other domestic and international partner institutions.

Conceived of almost a hundred years ago, Palomar Observatory has been at the forefront of astronomical research since mid-century. Today, the observatory operates every clear night and is an iconic facility for scientific advancement, instrument development, and student training.


Caltech’s Palomar Observatory is located in the remote wilderness of northeast San Diego County in Southern California. It is home to three major research telescopes: the 60-inch telescope, the 48-inch Samuel Oschin Telescope, and the 200-inch Hale Telescope, which for decades was the largest and most prominent optical telescope in the world. The observatory was conceived in the 1920s, and developed over the next two decades by a team of engineers and scientists led by American Astronomer George Ellery Hale—for whom the 200-inch telescope is named. Hale secured funding from the Rockefeller Foundation in 1928 to build the 200-inch telescope and observatory facilities. By the late 1940s both the Hale and Oschin telescopes were in scientific use by astronomers from Southern California and all over the world—a research mission that continues today.

The legacy of astronomy research conducted at Palomar spans humankind’s present understanding of the cosmos. Over its history Palomar astronomers pursued the precision measurement of cosmic expansion as the cornerstone of physical cosmology; framed our understanding of galaxy formation and the associated supermassive black holes at their centers; charted stellar life cycles, populations, and nucleosynthesis as the origin of chemistry that makes life on Earth possible; and surveyed the complex and intricate architecture of the Solar System. Palomar astronomers also developed novel instrumentation, vastly increasing the observational power of telescopes, and opening important new windows onto the observable universe. During this same period the observatory and the research it hosted became internationally iconic—capturing the imagination of science enthusiasts the world over, and inspiring generations of young people to pursue careers and passions in technical, engineering, and scientific disciplines.

Palomar Observatory remains an active center of astronomical research, student training, new instrument development, and public engagement. An international community of astronomers use Palomar telescopes and instruments every clear night to pursue current scientific questions. Private, US national, and international investments in new instrumentation, operations, and analysis methods keep Palomar capabilities and research at the forefront of modern astronomy. And the observatory remains committed to inclusively sharing its history and ongoing mission with visitors both on-site and remote.

Upcoming guided tour.