Sundials - World's Oldest Clocks

North American Sundial Society

St. Louis  

Sundial 777
State/Province:  Missouri Country:  USA
Dial Type:  Equatorial Condition:  Excellent
Latitude:   38° 36.915' N Longitude:   90° 15.458' W
Location:
  • West end of Linnean House
    Missouri Botanical Garden
    4344 Shaw Blvd.
    St. Louis
 
Description:
  • A cast aluminum equatorial dial 15 inches in diameter with a rotating, two-part, three-dimensional analemmic gnomon; this is a classic Schmoyer dial completed by Bill Gottesman. One gnomon half is used from summer solstice to winter solstice; time is shown by a beam of light passing through the gnomon slit to fall on the hour ring. The other gnomon half is used from winter solstice to summer solstice.

    To read civil time, the gnomon is rotated to present the appropriate face square to the sun, allowing a narrow beam of sunlight to fall on the hour ring. Near the summer and winter solstices, the gnomon requires an additional adjustment by sliding along it polar axis. Properly set, the dial shows civil time accurate typically within 5 minutes.
 
General Information:
  • Owner: Missouri Botanical Garden
  • Designer: Richard L. Schmoyer
  • Builder: Bill Gottesman
  • Construction Date: August 2008
 

Last Revised: 8/4/2014 8:38:45