2012 South facing sundial

The south facing dial.
Figure 1: The south facing dial.
The home that houses InFINNity Deck was built in 2012. Already during construction, well before the observatory was anticipated, the idea was born to place a vertical sundial in the south facing wall of the living quarters. The dial is made from Belgium freestone in combination with a brass gnomon.
It was designed using DialMaker and Orologi Solari. I used two packages to ensure that the design was correct. In order to find the declination of the wall, it was surveyed using the 1999 Leica TCRA 1101 with a Roelofs sun-prims, both from the geodetic collection.
Using CAD software the output of above packages was used to create the final design that now ornaments the wall. Before the actual freestone slab was engraved a mock-up was made of wood and a print-out of the drawing. This was then placed in the purposely created recess in order to test the design.
After having passed this test a local stonemason company was contacted to assist in creating the final dial. The largest challenge turned out to find a method to accurately engrave the dial in the Belgium freestone. The normal procedure for them was to cut a rubber matt using a computerised cutting machine, lay the matt over the slab as a template, and then sandblast the pattern.


A close-up of the south facing dial.
Figure 2: A close-up of the south facing dial.
Being such an intricate pattern, the cutting of the rubber matt failed as the rubber turned out to be too flexible.
Finally the solution came from modern technology. Instead of using sandblasting, the engraving was done using laser light (Luce Fecit would have been an appropriate motto). The process took a whole day, but in the end the dial was engraved to a depth of 1 millimetre.

Design features
The outer rim of the dial shows the time in MET winter time, divided into 15 minutes intervals. The whole hours are annotated with Roman numerals in subtractive notation. In between them the half hours are marked with engraved diamonds. On the inside of the rim the whole hours lines are extended and point-shaped. Along the lower edge a smaller point indicates the local meridian at 12:41MET.


Testing the sundial against a radio-controlled clock.
Figure 3: Testing the sundial against a radio-controlled clock.
On the inside of the hour-rim 7 date-lines are engraved to mark the periods of the zodiac, the ends of which are decorated with their respective zodiacal signs. Along the 12:00MET line an analemma is engraved with dots representing the first day of each month. The shadow of a nodus on the gnomon indicates the time of year.
In the upper corners a seahorse is shown at the left and a mariner's cross-staff at the right. The seahorse is the trade-symbol of the hydrographic surveyor, which I am, while the mariner's cross-staff represents the PhD-research I did for 17 years on that and related instruments. Together they represent me as the maker of this dial.
Between these symbols the Latin motto Horas non Numero Nisi Serenas (I do not count the hours unless they are sunny) and below that Anno MMXII indicates the year of creation.
In case the gnomon ever gets damaged or lost, a new one can easily be reproduced as the dimensions are all shown in the sundial. The upper screw-hole of the gnomon is the exact location where the gnomon should enter the slab, while a small brass round insert just above the meridian indicator represents the projected location of the lower end of the gnomon. A second brass insert just outside 4:15pm represents the triangular shape of the gnomon (the triangle is formed by the upper screw and the two brass inserts). Finally the lower screw represents the projected location of the nodus.
As the south facing dial gets shadowed by the gutter at around 5pm, a second, west-facing sundial, was created in 2017.


If you have any questions and/or remarks please let me know.

Testing the mock-up during the construction-phase of the house.
Figure 4: Testing the mock-up during the construction-phase of the house.
 
The freestone slab being cut with a laser.
Figure 5: The freestone slab being cut with a laser.

The gnomon with nodus still shining on the just installed sundial.
Figure 6: The gnomon with nodus still shining on the just installed sundial.
 
The meridian passage at the summer solstice.
Figure 7: The meridian passage at the summer solstice.

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