Equation of time (EoT)
Edition - may be copied
"The time difference between Local Apparent time (apparent solar time) and mean solar time at the same location. Its value varies between extremes of about +14 minutes in February and -16 minutes in October" (J. Davis (Ed), BSS Sundial Glossary. 2004). In order not to do mental arithmetics a plaque of EoT should be positioned near a sundial or engraved on the dial face. We offer EoT plates made of brass 3 mm sheets cut out according to the golden section.
Dimensions:
118 X 73 mm
138 X 85 mm
150 X 93 mm
Polished or patinated finish.
If you buy a sundial as a gift, do not forget, please, to order an anniversary line. At the appointed day the shade on a sundial face will move along a specially calculated line. It may be a birthday, wedding day, or any other day you like.
According to a centuries-old tradition a motto or a dedication is advisable on a sundial face. You may choose a motto from the list or suggest your own one. Mottoes and anniversary lines etched on sundials in stock are free.
The duration of solar day is changeable within a year. Thus the difference between clock and sundial indications may be as high as 15 min depending on the season. You may easy convert solar time into mean time and vice versa using the equation of time table or graph. Usually I make it of brass, copper or stone.
