Sundials - World's Oldest Clocks

North American Sundial Society

Galveston  

Sundial 318
State/Province:  Texas Country:  USA
Dial Type:  Equatorial Condition:  Good
Latitude:   29° 18.033' N Longitude:   94° 47.540' W
Location:
  • Ashton Villa House Museum
    Harris Garden
    2302 Broadway
    Galveston
 
Description:
  • This is an equatorial dial 3 x 4 feet tall, set up for the latitude and longitude of Galveston Texas. Corrections for the Equation of Time are cut as an analemma into the broad gnomon that rotates on a polar rod. The Equatorial time ring has hour lines viewed as standard time or DST at 5 minute intervals.

    The dial started when one of the Galveston residents constructed a park to honor his grand father. Bill Swann proposed to put a dial in one corner. His friend liked the idea. The park architect wanted the dial to be long lasting and suggested that it be made of galvanized steel. The dial is made out of rolled flat bar with a cross section of 3/4 x 4 inches.

    The dial itself was patterned after a dial which was located at Swann's college campus- Vanderbilt University. That dial was designed by the late Professor Dillard Jacobs. While Swann did not remember the specifics of that dial, the memory of it set the quest to decipher the suns orbit for this Galveston sundial. The time is displayed from a shadow cast onto a time ring. The "operator" pivots a plate, facing it toward the sun. The inscription on the
    plate reads "Face bar towards sun-Read time at month's shadow". The plate has a cutout in the shape of the analemma. Where the shadow cast by this
    cutout falls on the time ring specifies the time. Swann remembers that he "stayed out quite late one night to align the dial to a point in the sky near the north star."

    The sundial design is identical to the design of dial # 344 on the NASS web page. The metal forming techniques are different. Swann has been in contact with the designer, Peter Swanstrom.
 
General Information:
  • Owner: Ashton Villa House Museum
  • Designer: William Swann
  • Builder: William Swann
  • Construction Date: 1966