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On Feb 13, 2005, at 11:10 PM, Frank Reed wrote:

>
> Fred you wrote:
> "There are no alignment adjustment screws in the mounts of all prism
> scopes of which I am aware. "
>
> If I have it right then, the feature that you like about the inverting
> scopes is not that they're inverting but he fact that they have
> adjustable alignment (which would make good sense). Yes?
>
> And:
> "If it's out, there's nothing you can do to
> bring it back.  I bought one about a year ago that was out. "
>
> Interesting. Were you able to estimate by how much? Also, I realize
> that this is a "low-class" solution but did you experiment with
> shimming it?
>
> -FER
> 42.0N 87.7W, or 41.4N 72.1W.
> www.HistoricalAtlas.com/lunars
>

First, perhaps an expert would know how to adjust the collimation on a
modern prism sextant scope.  But I see no screws for doing that on
mine, and disassembled it and examined it carefully.

I don't think shimming would work.  The fork is u-shaped piece that's
bolted to the tube of the scope; it's quite narrow and custom cut to
fit the tube.  I suppose I could grind it, but I'm no instrument
machinist!

I'm guessing my prism scope was out about 4 inches at about 20 feet,
about a degree.

As well as being adjustable, the SNO-T additionally has cross hairs and
is reasonably light, since lacking prisms.

My main point was to check any scope before doing lunars or other
high-precision work.  I believe Joel Jacobs would allow return on an
item were it unsatisfactory.

Fred

   

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