Welcome to the NavList Message Boards.

NavList:

A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding

Compose Your Message

Message:αβγ
Message:abc
Add Images & Files
    or...
       
    Reply
    Re: Lunar Scopes
    From: Fred Hebard
    Date: 2005 Feb 13, 19:34 -0500

    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 CHO-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 CHO-M sextant was handy, so I fitted the scopes to it, and
    > not a CHO-T, and the reseults were as noted.
    >
    > I published pictures of these scopes on a Tamaya MS 1 sextant and a
    > CHO-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{at}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/
    >  >
    
    
    

       
    Reply
    Browse Files

    Drop Files

    NavList

    What is NavList?

    Join NavList

    Name:
    (please, no nicknames or handles)
    Email:
    Do you want to receive all group messages by email?
    Yes No

    You can also join by posting. Your first on-topic post automatically makes you a member.

    Posting Code

    Enter the email address associated with your NavList messages. Your posting code will be emailed to you immediately.
    Email:

    Email Settings

    Posting Code:

    Custom Index

    Subject:
    Author:
    Start date: (yyyymm dd)
    End date: (yyyymm dd)

    Visit this site
    Visit this site
    Visit this site
    Visit this site
    Visit this site
    Visit this site