Hi Mac and Sundialists,
Unless the panes of your window are **VERY** irregular in their
thickness there will be no effect on the angle of the emergent light beam.
It will be *parallel* to the entering beam. The exiting beam will *not* be
a perfect continuation of the entering beam. It will have been shifted,
although the angle will still be identical. The fact that it goes through
several panes doesn't matter much, the refraction at the first interface is
'undone' at the next in the case of panes of glass.
There are other subtle effects though - One I've long wanted to see if I
can use in a sundial design is a subtle polarization change effect on the
light. I haven't sorted out what to do with it yet.
Another effect is that at each air/glass interface a certain percentage of
the light is not transmitted, but is reflected internally in the glass or
off of the air/glass interface instead. With each pane added, the
penetrating light gets dimmer. This light isn't lost, It is what you see if
you look at the sun reflecting off a clean pane of glass - It can be
blinding.
I would love to design a sundial that uses these properties in a novel way
- using both shadow (or spot of light ) and reflection at the same time!
It would be nice If I could work in some polarization...
Does anybody know where to get large sheets of clear polarized material
that isn't too expensive?
Thanks
Chuck O'Connell
[EMAIL PROTECTED]
