NavList:

Alexandre E Eremenko wrote:

>>The concept of both methods is the same.
>>   
>>
>
>The method of IC correction does not involve sighting
>with your eye at all. You use your eye only to measure
>the distance between two spots with compasses and ruler.
>
>In the collimation method, one uses the sight
>(through the telescope, to see the laser spot).
>The laser beam only replaces the sight over vanes.
>That's why I don't see the advantage of this method
>in comparison with the "classical" method.
> 
>

"Both methods" referred to the two collimation methods that you had
iuxtaposed in your question: <>"What is the difference between this
collimation test and the ordinary one recommended on the book".

Yes, as I said: "The laser level replaces the sight over the vanes."

I don't know whether Frank claimed that his method is more advantageous.
I didn't. I leave it to him to argue this. I would say that having to
look only through the telescope while fiddling with the adjustment
screws is certainly no disadvantage. More importantly, I suspect that it
has the potential of higher accuracy. I will find out as soon as I
receive my laser level.

>>It is a feature of the receptacle for the scope, not the scope itself. I
>>have it on one of my sextants.
>>   
>>
>
>What sextant is this?
> 
>
It is a C. Plath from the fifties. I have seen the same mechanism on a
photo of a C. Plath of ca. 1885.

Here are the photographs. Sorry for the quality. There has been one
squall following the other all morning here in Connecticut and I have
virtually no daylight.

http://www.poorherbert.org/paralipomena/collimation/

Herbert

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