Hale Telescope

The Hale Telescope is a reflecting telescope at Palomar Mountain Observatory in California, featuring a 200-inch (5.1-meter) primary mirror made of borosilicate glass. The movable structure weighs 500 tons and rests on hydrostatic bearings that allow precise tracking motions.

Construction began in the 1930s and the instrument was completed in 1949, making it the world's largest telescope for 27 years. The mirror glass was cast during World War II and ground and polished over many years.

The name honors astronomer George Ellery Hale, who spent his career building large telescopes and started this project. Observers worked inside a capsule in the beam path to measure starlight without extra mirror losses.

A small motor of only one-twelfth horsepower moves the entire structure, enabling precise alignments needed for astronomical observations. The dome offers guided tours where visitors can see the telescope up close without disturbing measurement programs.

The facility identified quasars for the first time through spectral analysis, expanding understanding of distant cosmic objects. Researchers could position themselves at prime focus inside a capsule to measure directly without extra optical elements.

Location: California

Location: Palomar Mountain Observatory

Inception: 1948

Elevation above the sea: 1,713 m

Part of: Palomar Mountain Observatory

Website: http://astro.caltech.edu/palomar/about/telescopes/hale.html

GPS coordinates: 33.35628,-116.86489

Latest update: December 5, 2025 22:26