Sundials - World's Oldest Clocks

North American Sundial Society

San Ramon  

Sundial 726
State/Province:  California Country:  USA
Dial Type:  Bow-String Equatorial Condition:  Excellent
Latitude:   37° 45.486' N Longitude:   121° 57.623' W
Location:
  • Chevron Corporation Headquarters
    6001 Bollinger Canyon Road
    San Ramon
 
Description:
  • This 5 x 5 x 6.5 foot stainless steel bow-string equatorial sundial is a precise heliochronometer with internal cam mechanism to correct for the Equation of Time. This exceptional dial is made of welded stainless steel sheet and weighs 330 pounds according to the designer Lee Palmer Stephenson. The dial face of the 60 inch diameter equatorial ring is marked with hour, half-hour, 15 minute, 5 minute and one minute lines and Arabic hour numerals showing PST and PDT.

    An internal cam-operated mechanism is adjusted by an exterior knob that when turned tilts the entire dial about the celestial north polar axis to implement EOT correction. A window below the equatorial ring displays the date set. The dial is accurate within +/- 15 seconds throughout the day.

    The dial was originally designed and built for the Chevron facility in La Habra, California. Designer Lee Palmer Stephenson sent a photo of the dial to his cousin Lynne Geries with the comment, "Herewith is the promised photo of the object which consumed all of my time for two years."

    When that Chevron facility relocated, the dial was moved San Ramon, California in 1999. This site is about 4 degrees north and west in latitude and longitude. The base was leveled at the new location and the dial never showed correct time due to the location change. NASS member Dudley Warner in 2011 worked with Chevron to modify the base mounting to tip the dial pedestal both south and east to correct for the new location. Opposed radiused nuts securing the base plate to the foundation studs secure the pedestal at its tilted position.
 
General Information:Inscription:
  • Owner: Chevron Corporation
  • THE HELIOCHRONOMETER
    SUNDIALS WERE MAN'S PRIMARY TIMEKEEPERS FOR AT LEAST 5000 YEARS. THE HELIOCHRONOMETER, THE MOST ACCURATE KIND OF SUNDIAL, SYMBOLIZES MAN'S CREATIVITY AND OUR COMMITMENT TO EXCELLENCE IN SCIENCE AND ENGINEERING.
    33° 54' 55" N 117° 58' 05" W CHEVRON OIL FIELD RESEARCH COMPANY 1983

    A second plaque commemorates its relocation and gives the new location as 37° 47' 29.3695" N 121° 57' 37.4826" W
  • Designer: Lee Palmer Stephenson of Cheveron
  • Builder: Lee Palmer Stephenson of Cheveron
  • Construction Date: 1981-1983, relocated to San Ramon 1999
 

Last Revised: 2016-01-28 22:49