8/12/2002: Digital sundial
 

http://cellar.org/2002/digitalsundial.jpg

You're kidding me, right? No, this is an actual digital sundial, as seen and sold at Digital Sundials International.

For 89 dollars or 91 euros you can have a clock that can only be used at your specified geographic location, that updates itself every ten minutes (which they call "remarkably accurate"), and can only be used when it's sunny.

And they don't mention whether it knows about daylight savings time.

Defeats the purpose?
 

Isint the point of a sundial to run without batteries?
Making it digital defeats this purpose.
It is a cool novelty idea tho

Re: Defeats the purpose?
 

It doesn't use batteries - check out the website. It filters the sunlight through a mask which allows through light for that particular time of day, as far as I can tell, which would be a pretty cool engineering trick. Only works in one geographic place though and would have to be aligned properly.

A neat solution to a problem I never knew I had.

Minor issue.

Dammit, I want a sundial on my watch, like Fred Flintstone does. I hope they get a portable version working soon.

COOL!
 

That is the coolest application for polarized filters that I have ever seen!

I would never buy this, but I would accept it as a gift.

Re: 8/12/2002: Digital sundial
 

I suspect it knows only about true solar time. Back in the 1960's Scientific Amarican's Amateur Scientist column published a description of a highly accurate sundial that could be adjusted to keep mean solar time, as a clock would.

But from the photo, it looks like you have to judge the relative brightness of the figures for the ten-minute intervals to read the time, probably with about two minute accuracy.

Re: Re: 8/12/2002: Digital sundial
 

Two minute precision. If it doesn't correct for true solar v. mean solar, the accuracy is much less than that.

When they get it down to the point where it shows minutes, I might consider one. If I have a window which faces the right direction. My house is lacking in useless decorative items (not to mention furniture), why not a geeky one?

Re: Re: Re: 8/12/2002: Digital sundial
 

Point well taken.

Another digital sundial...

http://www.deutsches-museum.de/ausst...s/e_sonne1.htm

I don't think these use either polarized light or holography, I might be mistaken.