Article of the month April

Style-less pole style sundial 1

On a pole style sundial, there usually is a shadow caster parallel to the earth’s axis.
In its simplest form this is a bar or post, often oblique to the sundial plane.

But this pole style can be replaced by a single shadow-casting point.
A small ball, for instance, supported by a post that is square to the dial face.

Now, there are many places where such a post with a ball, or index, may be placed, and Figure 1 shows some possibilities.
The index is always square over the sub-style and so the distance to the sub-style may vary.

The pole style itself is now no longer necessary, and may be omitted.

Figure 1

Another thought is to leave out even the bar and index, replacing them with the observer.
He will be standing upright, and the head can be the index for a largish horizontal sundial.
Since not all people are the same height, the horizontal plane should have a scale for the different heights of persons.
I first saw such a sundial in 1987 in Bad Mergentheim, Germany. Here is a photo.
The hour lines in this sundial are made with colourful flowers.

The pole style visible in the picture is just an instructive demonstration prop.
The guide is standing on the height scale, his head is the index for the sundial.

Note: The sundial is, unfortunately, no longer present.