Sundial of the month April

One of the top ten of modern Dutch sundials is in Zoetermeer.
The hour line face is an equilateral triangle with 5.2m sides. The style triangle, likewise equilateral, is built in three parts, each of differently coloured granite. The parts as well as the circular aperture have a symbolic meaning, to which we will revert later.

Why does this sundial seem out of place?
Anyone at all knowledgeable in sundials would find a style triangle with sixty-degree corners odd for this location.
The style should point towards the celestial pole, and therefore the angle between the style and the horizontal plane should equal the local geographical latitude.
Oslo, for example, lies on 60 degrees latitude, and an equilateral triangle would make quite a suitable style triangle there.
The latitude of Zoetermeer is 52 degrees, so does that not make this monumental sundial out of place there?

Have another look at the photograph: the south side of the hour line face is higher than the north point. And that is the solution - the style does point at the celestial pole after all, for the concrete hour line face is tilted 8 degrees, making the style angle 52 degrees. Therefore, the primary demand for a pole style sundial is satisfied, while still maintaining a strict, geometrical appearance.

This sundial reads not only time (the correction for longitude is incorporated in the layout of the hour lines), but the date as well.
To this end, a hole was made in the south side of the style triangle. When the sun is at its highest point, at true noon, it will project a spot of light on the date scale drawn on the opposite inside of the large circular aperture.

The symbolism in this sundial may not be immediately apparent.
The style triangle is built from polished granite slabs in three colours: red, black and blue, symbolising the elements Fire, Earth and Water.
The circular aperture refers to Air.

Thibaud Taudin Chabot, committee member of the Dutch Sundial Society, designed this sundial; it was installed in 1993.

Should the City of Oslo desire a sundial of this design, the concrete slab would have to be horizontal. Transporting the Zoetermeer sundial there would perhaps not be wise; it weighs ca. 21600 kg or 47600 lbs.

Hans de Rijk.
Design and counselling: Thibaud Taudin Chabot.
See B93.3 pp16-17, 46.