Our Sundial
For the western front of our house we have built a large sundial. The corrections given by the equation of time are incorporated into the scale, so the sundial reading will give the exact middle-european wallclock time.
The twofold legend of the hourlines allows to read the time for two different time zone, or alternatively as summer and winter time. The datelines denote the first day of each month and the first day of each sign of the zodiac. In order to avoid an "optical overload" and too many lines on the clock face two different dial plates have been manufactured. The are exchanged against each other at the dates of solstice. The measured deviation from the exact middle-european wallclock time is 30 seconds at maximum. Therefore we may honestly call it a precision sundial.
The sundial has a size of approx. 1.4 meter and comprises an adjustable hidden mounting structure and an exchangeable front plate. For the projection of the shadow I use a nodus with small hole. According to the priciple of a pinhole camera this aperture projects an image of the sun onto the dial plate thereby indicationc the exact time.
I have calculated, constructed and manufactured this sundial by myself. The design if registered with the German Patent and Trademark Office.