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Hi Frank:

Thanks for that link.  They archive the sunrise and sunset times along
with other more frequent data and then send the data to a satellite.

Very cleaver and much easier than I was thinking of.

Have Fun,

Brooke Clarke, N6GCE
--
w/Java http://www.PRC68.com
w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml
http://www.precisionclock.com


Frank Reed wrote:
> Brooke C you wrote:
> "Suppose that a clock  that keeps UTC time to within 1 second has a photo
> sensor with an analog  output to a computer.  The clock is indoors but
> the room has a window to  the outside so although the clock is in the
> shadow of the Sun it does see a  daily brightness curve.
> How accurately can the clock determine where it is in  the world?"
>
> This exists.
> In fish tags!! I've posted on this before.  Here's something I wrote
> previously:
>
>>>This technique of navigation is  actively employed on a small device that
>
> operates in an area inaccessible to GPS  signals --underwater. Do you have
> $4200 to spare? Then you, too, can be the  proud honor of a celestial navigating
> fish tag. I brought this up briefly on the  list over a year ago. Here's a link
> to their web site and a description of the  device:
> http://microwavetelemetry.com/Fish_PTTs/archival.php
>
> They get  one-degree-ish estimated accuracy in latitude and longitude by
> timing sunrise  and sunset (based on light levels corrected for depth, which is
> measured by  pressure). <<
>
> -FER
> 42.0N 87.7W, or 41.4N  72.1W.
> www.HistoricalAtlas.com/lunars
>
>
>

   

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