Cesar Chavez Memorial Solar Calendar

Solar Calendar site in February 2018.  
Santiago Casal speaking
Explanatory sign relates position of stones to solstice and equinox
Base of the Solar Calendar
Base of solar calendar, detail
Base of solar calendar, detail

The park bears the name of Cesar Chavez.  That would be an empty label without some monument inside its borders.  Instead of a statue, which Chavez would probably have hated, the park has the Cesar Chavez Memorial Solar Calendar, solarcalendar.org

Chavez was not only the leader of the modern farmworker movement, he was at heart a tiller of the soil and a grower of crops.  He knew not only the hopes and fears of farmworkers and their families, and the devious schemes of the captains of agribusiness, but also the cycle of the seasons, the positions of the sun and the moon, and the virtues required to make a living in harmony with the earth.  The farmworker movement was not only a labor movement but a struggle for environmental justice. 

The person who put these qualities together here in the park and made a monument of them is Santiago Casal, founder, architect and curator of the Cesar Chavez Memorial Calendar.  Sited on the  western ridge with a sweeping view of the Bay, the calendar is one part astronomy, one part moral and political education, one part community meeting place, and one part public art. 

At the center sits a stone calendar.  An upright pillar, called a gnomon, casts a shadow over an intricately engraved and inlaid concrete base.  Casal designed and built this complex and artful calendar with his own hands.  It is not a sundial, which tells the time, but a meridian calendar.  A savvy viewer can determine the current date from the position of the gnomon’s shadow at solar noon.  That’s not exactly clock noon, but you can look up the approximate solar noon time for each month on a table provided at the site.  If you put a coin or some small marker at the tip of the shadow for one minute, you can watch the earth moving.  

The summer and winter solstices and the equinoxes each have their markers.  On these occasions, the site plays host to a gathering of the tribes, where friendly experts such as Lori Lambertson, Rabbi David Cooper, or Alan Gould explain the basics of astronomy and decipher the markings on the calendar’s base.  Casal is a student of solar calendars around the world and has a high respect for Maya astonomers, in particular. 

Surrounding the calendar sits a quartet of stones engraved with the four virtues of Chavez’ movement:  Determination, Courage, Hope, and Tolerance.  A set of explanatory signs introduces the casual visitor to the meaning of the monument. 

The memorial has its own website, solarcalendar.org.

For a set of photos of the calendar in December 2014, click this link.  Google Maps also has a 360-degree Street View of the calendar site.  

Here are links to some of the recent gatherings at the calendar on solstice and equinox evenings:

Building the Cesar Chavez Memorial Calendar was itself a long struggle.  Here are some links for background:

Lori Lambertson of the San Francisco Exploratorium explains the equinox at a Solar Calendar gathering
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