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I am most specifically not intending any insult to Joel Jacobs with the
following.  He is a fair, honest, scrupulous merchant, in my experience
and opinion.  With that said, if you do buy another telescope for your
sextant for lunars or other high-precision work, it is an excellent
idea, in my experience, too check that the telescope is properly
aligned when mounted on your sextant.  One advantage of the inverting
Russian (Cho-T) scopes is that they can be aligned; most prism
telescopes cannot be aligned.

On Feb 12, 2005, at 5:48 PM, Yourname Here wrote:

>
> Hello Alex, Bob, and Group,
>
> I will try and answer both your questions in a way that may be of
> benefit to everyone. What I omitt here, I will respond off group if
> you have any further interest in discussing it.
>
> Most all well known contemporary sextants use the same fork or rising
> piece design so that many sextant scopes are interchangable with each
> other. It is easier to list which sextants most scopes wont fit than
> the other way around. Sextants that have a unique design to their fork
> are the Dutch Obseravtor, French Poulin, German Freiberger, USN MK II,
> and likely some English designs with which I am not familiar. Those
> are the ones the three high powered scopes I mentioned will NOT fit.
> Therefore, you can conclude they will fit most others.
>
> That said, the limiting factor to most of the sextants with the same
> fork design will be the size of the INDEX MIRROR. Any index mirror
> with a vertival demension of greater than 49 mm will hit the top of
> the objective lens, and stop the travel of the index arm on two of
> these scopes. Both the SNO-T, C&P and all other large mirror sextants
> will not read below 41 degrees if the 7 x 50 scope is fitted, or 21
> degrees if the Shonan 6 power scope is fitted. The Tamaya 7 x 35
> scope, because of the smaller diameter of its objective lens will
> allow full index arm travel on all sextants other than those I named.
> If in doing your Lunar sights, you need the full range of travel, then
> make sure you have a mirror the size of the Tamaya MS 1 series
> sextants to which all three of the scopes were fitted.
>
> For Alex,
>
> The two Tamaya scopes were made in the 1970's. They both are in
> excellent condition. The Shonan scope was dropped and there is a dent
> in the objective lens ring, but this does not appear to have affected
> images as viewed.
>
> From an old Nautech catalog, the Degrees of View are:
>
> 7 x 35, 6.5 degrees
> 7 x 50, 7.1 degrees
>
> The Shoan is marked on the scope 6 power, 6 degrees.
>
> A Russian SNO-M sextant was handy, so I fitted the scopes to it, and
> not a SNO-T, and the reseults were as noted.
>
> I published pictures of these scopes on a Tamaya MS 1 sextant and a
> SNO-M sextant. The two higher powered scopes are very rare and you
> likely will not come across them, but they are an interestng bit of
> sextant history. To view GO:
> http://www.villagephotos.com/pubbrowse.asp?folder_id=1217241
>
> If anyone wants more information, please contact me off group.
>
> Cheers,
>
> Joel Jacobs
>
>
>
>
>
> -------------- Original message from "Robert Gainer"
> : --------------
>
>
> > How much for the 7X50 and does it fit a C&P sextant?
>  > Thanks,
>  > Robert Gainer
>  >
> > >From: Yourname Here
>  > >Reply-To: Navigation Mailing List
>  > >To: NAVIGATION-L@LISTSERV.WEBKAHUNA.COM
>  > >Subject: LUNAR SCOPES
>  > >Date: Sat, 12 Feb 2005 13:32:10 +0000
>  > >
>  > >For those who practice the art of Lunar distances, I have three
> rare high
>  > >powered sextant telesopes, each with a fork that will fit most
> contemporay
>  > >sextants.
>  > >
>  > >7 x 35 Tamaya Prismatic
>  > >7x 50 Tamaya Prismatic
>  > >6 x 6 degrees Shonan Kosakusho ( WW II searchlight manufacturer)
>  > >
>  &! gt; >
> > >Joel Jacobs
>  >
> > _________________________________________________________________
>  > Express yourself instantly with MSN Messenger! Download today -
> it's FREE!
>  > http://messenger.msn.click-url.com/go/onm00200471ave/direct/01/
>  >

   

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