Hello All, Does anyone have to hand the approximate distance over which a pinhole gnomon is useful, please? I'm sure it is probably out there along with all the shadow sharpener discussion - which I must re-read; but a quick refresher from those of you who have experimented with this design would be most useful in the meantime, (or any other time that pleases you). Also one must consider whether the thickness of the material that the pinhole is contained in will obstruct the rays of light intended to pass through it(especially when the sun is at a small angle from the wall), requiring material to be removed from both faces around the hole.
Best wishes Sarah Edmondson-Jones