Kurt, are you familiar with polarization-type sundials? They work even on overcast days, since the diffused sunlight scattered through the cloud deck retains it's polarization orientation. Of course, instead of looking down at a shadow, you'd be looking up through a tube, through crossed polarizing filters, and then noting the relative angle between the two at the setting of either greatest extinction, or greatest transmission, depending on how that particular sundial was set-up. I've read that the Vikings used crystals with polarizing properties to estimate solar altitudes and azimuths when at sea, on overcast days. I'm at work now and can't do the instant research, but I'm sure there is more on this on the Web somewhere.
From: Canopus56 <canopus56@yahoo.com> I'll probably walk over to the Gallivan Center at around _12:30pm_ to watch the Gallivan sundial tick off local equinox.
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