This is similar to my Physics.SE question Microtops sunphotometer sun target optics - there I was asking about the optics principles (the answer is no good for my understanding, but I have been able to figure it out myself).
The purpose behind a sunspotter is to show when a device is lined up in direct view of the sun - vital for fields such as sunphotometry etc.
This question is given that I now understand the optics principles involved (similar to a magnifying glass, but smaller and does not burn when focused) - what method can be used to make a rudimentary sunspotter?
In particular, I am interested in:
- a suitable material that would be used for the sun target (as per the Microtops picture on the linked page).
- the same orientation of the sun target being perpendicular to the incident light.
What I am not interested in:
- any device how to make a device that allows viewing of things like eclipses.