NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: C.Plath on Ebay
From: Alexandre Eremenko
Date: 2005 Jun 13, 04:13 -0500
From: Alexandre Eremenko
Date: 2005 Jun 13, 04:13 -0500
Cortney, I qm traveling now (without my sextant). Will come back on June 28 and tell you the adjusting procedure. Alex. On Fri, 10 Jun 2005, Courtney Thomas wrote: > Assuming the inverting scope of the -SNO-M to be like the SNO-T: > > Would the 8 screws on the barrel mount bracket, nearer the end opposite > the eyepiece...be the collimation adjustment on the SNO-M ? > > Or only 4 of them ? If yes, which 4, the most or least, forward ? > > If yes, do you know the proper adjustment sequence ? > > Thanks again, > > Courtney > > > On Fri, 2005-06-10 at 15:01, Alexandre Eremenko wrote: > > In Russian sextants, collimation adjustment is > > not a feature of the sextant, but a feature of the scope. > > I have never seen an SNO-M in real life, but from the pictures > > I conclude that they come with two kinds of scopes. > > (Like SNO-T). It is the UNIQUE Russian INVERTING SCOPE > > which has the collimation adjustment. > > I have not seen ANY other scope like that, and I wonder why > > all Call Nav books still mention this adjustment > > (which cannot be made on anything but this Russian inverting scope). > > > > All kinds of Russian sextants and scopes that I know can be seen in > > http://www.maurnavy.com/index.html > > Picture 2 shows an SNO-M with inverting scope (which has collimation > > adjustment). > > Picture 1 shows an SNO-T but with ordinary (straight) scope. > > (New SNO-T come with two scopes: ordinary and inverting) > > Picture 4 shows some old sextant resembling SNO-M with > > some old scope (possibly inverting) > > which also has the collimation adjustment, > > but this is not the modern inverting scope. > > > > > > On Fri, 10 Jun 2005, Courtney Thomas wrote: > > > > > Then the SNO-M does not have the collimation error adjustment ? > > > > > > Thank you, > > > C.Thomas > > > > > > > > > On Fri, 2005-06-10 at 02:05, Alexandre Eremenko wrote: > > > > Yes, of course. > > > > This picture could be used in a beginner's > > > > textbook to explain what is "collimation error":-) > > > > Modern sextant scopes (for the reasons that excape me) > > > > do not have collimation error adjustment, > > > > with one exception: the inverting scope of SNO-T. > > > > Once Bill suggested to adjust collimation error > > > > with a hammer... > > > > > > > > This is apparently what the owner of this sextant did, > > > > and after he failed, he sells the sextant:-) > > > > > > > > Alex. > > > > > > > > On Thu, 9 Jun 2005, Robert Eno wrote: > > > > > > > > > Have a look at this sextant on e-bay. > > > > > > > > > > Are my eyes deceiving me or is the rising piece on the scope bent out of shape? > > > > > > > > > > http://cgi.ebay.ca/ws/eBayISAPI.dll?ViewItem&category=37971&item=7328115519&rd=1 > > > > > > > > >