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Thanks Fred. Helps if one does a search under the proper title to get
results.
I now know what this sextant looks like and how it was used. Interesting.

Here's a link for anyone interested:

http://silkpress.com/archive/discovery/autumn2005.ulugbek.shtml



Doug,

I can't help you out much with most of your questions, but one
comment is that the device probably was not a sextant in that it
probably did not employ the double reflection principle.  I would
expect it was a sighting tube of some kind, oriented in the north-
south axis, which could be pointed at various elevations to read off
the meridian altitude of a star directly.  A quick Google search
confirmed this conjecture.

Fred

On Mar 24, 2006, at 1:35 PM, Royer, Doug wrote:

> Ok, I'm now reading a very good book dealing with observatories
> past and present.
>
> There is an interesting chapter on the Samarkand Observatory in
> Uzbekistan that Ulugh Beg built and used for astronomical
> observations in the 1400's.
>
> There is a crude description of the FAKHRI SEXTANT used by the
> Samarkand Observatory that was used to measure the position of
> thousands of stars to within a few seconds of arc. It has a radius
> of 120 ft.
>
> After a quick search on the web today for pictures or a better
> description of this sextant I came up dry. There are a few pictures
> of parts of the observatory but none that are identified as the
> Fakhri sextant.
>
> There is 1 picture of a section of a structure which has 1 vertical
> stone wall on each side of a center groove and 2 stone tracks
> running in a vertical arc between the 2 walls on either side of the
> center groove.
>
> I had pictured this "sextant" as kind of matching how Stonehenge is
> constructed for celestial observations. But now I'm more interested
> than ever to find what this "sextant" really looks like.
>
> Frank, because you're an astronomer, can you help or point me in
> the proper direction to get a better understanding of what this
> looks like? Visually or at least a better written description. Or
> can anyone else help out in this quest?
>
>
>
>

   

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