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The Botswana Solstice Machine

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#1 Olivier Biot

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Posted 16 February 2012 - 06:15 AM

The Botswana Solstice Machine

By Carl Dori.

#2 etudiant


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Posted 16 February 2012 - 02:21 PM

There is a similar, albeit much larger structure in northern Chile, outside of Antofagasta. It however lacks the neat shadow tube, but rather has the form of an open gate, with a round plaque inscribed with the tropic line in the floor.
Presumably the shadow of the top of the gate will fall on the tropic line on Dec 21.

#3 barbarosa


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Posted 17 February 2012 - 01:28 PM

What an amazing find.

I hope someone is able to tell us something about the person or group that placed it.

Sadly here in a first world nation, such a monument would have be vandalized; defaced first and then any brass or bronze stolen.

#4 roc.ls1864



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Posted 17 February 2012 - 10:20 PM

As a land surveyor by day and astro-nut by night I found this article very interesting and the photos are good too. I would like to know more about it too, particularly how it was determined where to place it so as to be on the correct latitude. Nowadays with GPS so common that housewives use it to find grocery stores, latitude and longitude are taken for granted by many, but there determination is a real bit of a measuring trick without GPS. Latitude is not as difficult to get roughly but I would think since this monument seems to work so well more sophitiscated astronomical observations were used, rather than the simplest "drive a stick in the ground" method. Longitude is a different matter and I would encourage anyone interested in such matters and the history of how these determinations, so important in navigation, were developed to read the short but very good book "Longitude" by Dava Sobel.

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