This is a type of plane sundial clock, with the clock plane parallel (horizontal) to the earth's surface at the sundial location. The shadow produced by the tip of the gnomon on the clock plane is used to read the hour and the day.
The horizontal sundial is very appropriate for use in public places, as this style clock does not interfere with pedestrians or scenic views.
For high accuracy, the plane of the gnomon must be aligned with the plane of the meridian of the location. Therefore, when choosing a horizontal portable sundial, a magnetic compass is used (with corrections for magnetic declination) to determine south and the location of the meridian.
This sundial includes a calendar, and the proper corrections for longitude, the equation of time, and daylight savings time, in order to obtain the correct civil time.
The geometric dimensions of the clock used in the program are input in the screen DIMENSIONS.
