From the perspective of the earthly observer, the position of the sun's rotation axis changes over the course of the year (see image on the right). Anyone using a telescope to project the sun's disc onto a surface in order to observe sunspots must take this change into account if they wish to indicate the position of the spots with correct heliographic coordinates. A suitable aid for this are special templates, also known as Stonyhurst discs, which correctly indicate the coordinates for a specific time of the year. This set consists of eight such templates, which together cover the whole year.
The templates are very suitable for the Hossefield Pyramid, where they can be easily inserted. This allows you to correctly document the position of a sunspot and thus also the change in the local occurrence of the spots during a spot cycle.
