Stargazing at Sugarloaf

Sugarloaf Ridge State Park is the home of Robert Ferguson Observatory, Northern California’s most active
public observatory. It is also the largest observatory in the western United States completely dedicated to public viewing and education.

The dark night sky of Sugarloaf Ridge makes it a perfect location for stargazing and the observatory is open to the public on select weekends throughout the year for both night and solar viewing. Per-person fees are charged at the door for night viewing.

The Robert Ferguson Observatory is located near the group campground and is surrounded by a protective ring of hills, decreasing the light pollution from nearby cities. This astronomy observatory houses several telescopes. Our newest 40″ telescope has been installed. Come check it out.

For more information about stargazing events or to rent the observatory for your own stargazing party, see

Notes about Accessibility

Rooms, restrooms and routes to the telescopes are all accessible. Telescope eyepieces may not suit everyone’s needs. Call ahead to the observatory at 707-833-6979 to discuss your needs.

A designated accessible parking space is available in an adjacent lot. Route of travel from parking space is hard-packed gravel that is generally accessible. It may occasionally work loose and require some assistance, but the space is adjacent to the observatory.