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Frank,

     Excellent suggestions. I would add that fixed prisms may also do
the trick. For camera Sun observations my homemade Bris is working OK
strapped flush to the front of the lens using a rubber band.

Greg

On Dec 5, 11:54�am,  wrote:
> Greg, a couple of weeks ago, you wrote:
> "The Brissextant can be attached to a digital camera lens to create a hybrid 
celestial navigation instrument. I believe this would be the next sensible 
evolution of digital camera CN."
>
> It's an interesting idea. Bear in mind that you still have to "swing the 
arc" with a fixed-angle sextant (like the Bris) and you also have to align it 
carefully to ensure that the line of sight is collimated relative to the 
mirrors.
>
> "Does anyone know where I can get a Brissextant?"
>
> As others already mentioned, they're easy to make.
>
> You may also want to experiment with an ordinary fixed-angle sextant. To see 
what I mean, look at a standard sextant set to, say, 45 degrees. Now fade out 
all of the components except the index mirror and the horizon glass. They are 
the essential components that make the sextant work as it does. Afix those to 
a simple flat board replacing the sextant frame. The mirrors can be 
permanently glued to the board. They do not need to be adjustable. A 
fixed-angle sextant like this is easy to make. You could build a dozen of 
them, one for every ten degrees of altitude. And they can be quite compact, 
an inch or two on a side, like the original Bris sextant. The big advantage 
of the Bris design is that you get several fixed angles in one device. The 
disadvantage of the original Bris design is that it works primarily with the 
Sun, the Moon is you're lucky. A simple fixed-angle device can be extended in 
all the usual ways that sextants have evolved. You could hold one in front of 
a small spotting scope if you want higher magnification. You could add shades 
for viewing the Sun as well as the stars. You could even add some sort of 
adjustable arm and a scale to... wait, wait... we're back where we started. 
:-)
>
> -FER
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