Thibaud Taudin-Chabot wrote:
> That sundial is not 1 spot projected on the floor, but the whole
> sundial pattern projected on the floor. On the floor you only need 1
> readingmark, nothing more.
I understand; I mentioned it as an example of dark spots being projected
on the receiving surface, only...
> But the shadow of a spot on a window will be very difficult to find on
> a sunlit floor because the light of the sunlit floor is reflecting in
> every direction and also over the shadow spot so that shadow spot will be
> less clear.
> The bright spot of sunlight from a hole in a closed wall/ceiling will
> therefore much easier to find in a relative dark area.
True! This will impact the choice of surface material, I'm sure.
Dave
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