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The Robert Ferguson Observatory (RFO) is open to the public at least once a month, usually on a Saturday near the time of the New Moon.

This part star party/part Night Sky Trails is a hybrid version of these two events. While our dome and west wing telescopes will remain closed, we will allow small groups in our east wing to view images from our RC20, research-grade telescope. Sky tour docents will be stationed outside to give guests laser guided tours of the constellations. This is primarily an outdoor event. Only part of the observatory will be open.

Ticket cost is $10.00 per adult, $5 for students and seniors 60+, and children under 12 are FREE.  (Note: while children tickets are free, they are still required.)(Plus State Park parking fee of $10.00 per vehicle.) You MUST have a ticket to attend this event.  Attendance is limited and, while remaining tickets will be sold at the door, they will be subject to availability.

COVID-19 Update: Based on direction from Sonoma County, RFO is requiring guests to wear face masks at all events, regardless of their vaccination status.  And, of course, if you are not feeling well or have a fever, please stay home.


  1. Map and Directions
  2. When to arrive: We keep the observatory open as long as there are visitors, but you must arrive within 3 hours after start time to ensure that we remain open for you. Summer Star Parties begin with tours and presentations until it’s dark enough for observing.
  3. Bring warm clothing, even in summer—observing is done outdoors.
  4. There is a short walk from the parking area to the Observatory and you may wish to bring a small flashlight.
  5. White Light: No white lights should be used after dark; the observatory is a red-light-only area to protect everyone’s night vision. We will supply red cellophane to cover flashlights. Please note:
    ◦ Bring a SMALL flashlight (large camp lanterns, light sticks, etc., cannot be adequately covered by red cellophane).
    ◦ Cell phones or cell-phone flashlights are acceptable but must be covered in red cellophane. (No cell service at the observatory).
    ◦ Some head lamps are difficult to cover with red cellophane. Once covered, head lamps should be worn around the neck or used pointing down as they are usually very bright at eye level.
    ◦ Red flashlights are available for $5 at the observatory.
  6. Alcohol is prohibited on Observatory grounds.
  7. The Observatory is not open to the public except for scheduled events.

For current conditions call the observatory at (707)833-6979.
RFO is operated by the Valley of the Moon Observatory Association, a 501(3)(c) nonprofit organization, and all of the proceeds will go towards maintaining this beloved Sonoma county institution. For more info please visit the Robert Ferguson Observatory website. If there are additional questions, please email info@rfo.org.