Transit of Mercury, Monday morning 2016 May 9, is viewable in Bay area from sunrise (about 6am) until about 11:44 am if it's not cloudy. The transit cannot be seen with the naked eye. Transit of Mercury means the planet Mercury, which is a planet about 60 million miles from us and as small as our moon, will appear as a small dark dot moving slowly across (transit) the face of the Sun, taking over 7 hours for the entire transit. There are approximately 13 transits of Mercury each century. There won't be another transit of Mercury until 2019 Nov 11 and the one following that will be in 2032. From the first transit observation in 1631, transits of Mercury have had a significant role in history, from Captain Cook's voyages of discovery in the South Pacific in 1769, to helping prove Einstein's theory of gravitational warping of space. For more detailed information about this transit see:


Transit of Mercury iPhone image by Greg Barge

Photo by Greg Barge taken in East Sacramento with and iPhone and Orion SkyQuest XT8g with 9.45" ID Orion Full Aperture Solar Filter

Update Monday morning (May 9): Bay Area clouded out.

Sites to watch the transit online

Viewing sites that will have telescopes with quality solar filters:

Auburn - U Skies Astronomy - Local astronomers will be safely showing the transit of Mercury across the sun through their telescopes, which are designed to show the sun, in Auburn, at the American Canyon Overlook, also known as the Auburn Skateboard Park, on Pacific Street, from 6:00 AM until 11:42 AM. The viewing is free. If it rains or is very cloudy the event is canceled. To get to the Overlook, go to downtown Auburn, to the historic Courthouse. One of the roads branching from there is Auburn-Folsom Rd. Take that to the third stoplight (about 1 mile). This is Pacific Ave. Turn left at this stoplight and go about 0.6 miles to the American River Overlook, which is on your right. We set up at the far end of the parking lot. You can find information about all of our astronomy activities and our 2016 star party schedule at: Like us on Facebook at Follow us on Twitter at

Hercules - The Hercules Stargazers will hold a Mercury Transit viewing on Monday, May 9, from 9:30 a.m. to 11:45 a.m. at Foxboro Park, 1025 Canterbury Drive, Hercules. We will meet in the basketball courts behind the building. We have an excellent view to the east and usually clear skies. We will be set up by 9:15 or earlier, and welcome new visitors with solar-filtered scopes, as well as the general public. Take I-80 E to Exit #24 Rodeo, go left at the light, turn right at the next 4-way stop (Canterbury), drive up the hill past the next stop, and the park is a half block more on the left. Park anywhere on the street. Wheelchair accessible. Info: 510-526-5974, or email Dave at

Los Altos Hills - Peninsula Astronomical Society (PAS; will be observing Foothill College Observatory, 12345 El Monte Road, Los Altos Hills, from 8AM until 11:45AM for the transit of Mercury. Maps of the campus can be found at: The Observatory is in the 4000 building (round complex near top of campus map). Maps to the Observatory are also on the Peninsula Astronomical Society (PAS) website - will be a Coronado H-alpha telescope, a white-light solar telescope, and several other telescopes. Cloudy or poor weather conditions will cancel this event. Try checking our webcam out on transit morning to see if we are open at: This event is FREE to the public. Park in Lot 4. A $3 Parking Permit Fee is required by Foothill College available at machines in the parking lots. See also Bay Area Science Festival entry

Oakland - Chabot Space and Science Center, 10000 Skyline Blvd, Oakland, CA 946190; 7:30 AM - 11:30 AM Transit of Mercury viewing. Join us at the Chabot Observatory Deck to view this rare occurrence from our telescope, Leah. Our staff astronomers will be here to guide this exciting experience as we watch the transit all the way to its conclusion. Weather permitting. Website: Cost: $5

San Francisco - California Academy of Sciences: A couple of our docents who usually do sunspot-watching have expressed a strong interest in observing the transit from the museum roof, weather-permitting, from opening time (9:30am) to last contact at about 11:45am.

San Jose - San Jose Astronomical Association (SJAA) has an event planned at our basecamp, Houge Park in SJ.

All the details are in the Meetup: also Bay Area Science Festival entry

San Mateo - College of San Mateo (CSM) 1700 W Hillsdale Rd, has two observing sites:

    • The CSM Astronomy Dept will be doing a transit viewing at the rooftop Observatory in Building 36, 4th Floor - Viewing Deck, from 7:00am to 11:45am. Free parking in Olympian Lot 12. Parking $2 in all other visitor parking lots.
    • San Mateo County Astronomical Society (SMCAS) viewing party at the CSM College Center Building 10 Cafeteria Terrace (2nd Floor) which has a great view of the sun to the east as well as a beautiful view of the Bay. Plus, it's next to the Paws for Coffee shop and cafeteria for breakfast/snacks. We have arranged free parking in CSM lot 12. We welcome any other astronomers to bring their solar scopes.

Full details at: also Bay Area Science Festival entry

Sonoma County

    • Cloverdale - outside the physical science classroom at Cloverdale High School, 509 North Cloverdale Blvd., Cloverdale, CA.
    • Robert Ferguson Observatory (RFO) When: 7:00 AM - 12:00 PM Where: Kenwood, Robert Ferguson Observatory, 2605 Adobe Canyon Road, Kenwood, CA 95452 Cost: Free ($8 park parking) Bay Area Science Festival entry.

Walnut Creek - Mount Diablo Astronomical Society (MDAS) is setting up in Larkey Park, Lindsay Wildlife Experience, 1931 First Ave, Walnut Creek will have available approved special filters and solar scopes to observe and view the dark disk of the planet Mercury ... When: 7:00 AM - 11:30 AM Cost: Free. Bay Area Science Festival entry

Go here to watch live on-line:

Transit of Mercury 2016 NASA Resources -

NASA will stream a live program on NASA TV and the agency’s Facebook page from 10:30 to 11:30 a.m. -- an informal roundtable during which experts representing planetary, heliophysics and astrophysics will discuss the science behind the Mercury transit. Viewers can ask questions via Facebook and Twitter using #AskNASA. Roundtable participants include: Jim Green, planetary science director at NASA Headquarters in Washington; Lika Guhathakurta, heliophysics program scientist at NASA Headquarters; Nicky Fox, project scientist for the Solar Probe Plus mission at Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland; Doug Hudgins, Exoplanet Exploration Program scientist at NASA Headquarters.

    • NASA ScienceCast video on the rare opportunity the Mercury transit poses for professional astronomers and backyard sky watchers alike -
    • Images and animations for b-roll are available through NASA’s Scientific Visualization Studio -
    • For fast facts about Mercury, and more information on the 2016 transit of the sun, visit:

Bay Area Science Festival calendar - May 9