Hat Creek Radio Observatory, Radio astronomy observatory in Hat Creek, California, US

Hat Creek Radio Observatory is a research facility in California that studies the universe by listening to radio waves from space. The site uses multiple large dish antennas spread across the area to capture faint signals from distant stars and galaxies.

The facility was founded in the 1950s by the University of California Berkeley to investigate radio waves from space. It became a site of important astronomical discoveries that helped scientists learn more about distant objects in the universe.

The site is named after Hat Creek and its main instrument honours Microsoft co-founder Paul Allen, whose funding gave the array its name. Much telescope time is rented to the U.S. Air Force, which uses it to track satellites and space debris for the Space Surveillance Network.

The site sits at 986 m elevation in Shasta County, about 467 km northeast of San Francisco and roughly 290 km from Redding via I-5. The German source gives 1280 m, so confirm the route and access before setting out. Radio-quiet rules apply: switch off phones and GPS receivers near the antennas.

The observatory hosts one of three CHIME fast radio burst outriggers, built to pinpoint where these millisecond radio flashes originate. A large share of telescope time is rented to the U.S. Air Force, which tracks satellites and space debris under the Space Surveillance Network. The dish in view carries the marking "2B" on its concrete pedestal.