Analemma Variations

The Analemma calculations described in the previous post show the sun positions above the horizon, as only these could be visible in any given location. Looking here for design patterns rather than physics, in these images also the positions below the horizon are shown. This means that in some form the surface of a sphere (and not only a hemisphere) has to be projected into a plane – which is done in the way shown in Projective geometry - Wikipedia. The above image is a photograph of a plot of the analemmata for every 20 minutes of the day at the latitude of Switzerland – done with my Axidraw (see video at the end of this post)

The video below varies the latitude again from 90°N to 90°S, while showing the analemma for every 20 minutes of a day.

Variations of the first image play with different numbers of analemmata (i.e., different numbers of times of day) to look for the variation in the generated patterns.

Showing the analemmata for many times of day and simultaneously for multiple latitudes generates quite complex patterns - the first one captures mainly the patterns visible ‘above the horizon’

More interesting patterns get created by the projection of the hemisphere below the horizon:

Plotting with white is tough even using a Rotring pen (0.3mm) - later I selected the missing parts in the SVG and added these too.