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: Sextant Terms
    From: Nicol�s de Hilster
    Date: 2007 Oct 22, 08:46 +0200

    Dan Allen wrote:
    > IF a sextant:
    >
    > 1) has a frame with an arc of 60 degrees,
    >
    > 2) can measure 120 degrees due to the double reflecting principle,
    >
    > THEN
    >
    > 3) how can it measure 140 degrees?
    >
    >
    >   
    There are surveyors sextants (C. Plath for instant) that have an 
    additional pentagon prism attached. This prism adds 90 degrees to the 
    observed angle, so measuring 140 degrees should be no problem with that 
    prism attached.
    
    One has been for sale on E-bay recently: 
    
    http://cgi.ebay.co.uk/US-Coast-Guard-Weems-Plath-Sextant-w-Case_W0QQitemZ300160900331QQihZ020QQcategoryZ37971QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
    
    Nicol�s
    
    
    
    --~--~---------~--~----~------------~-------~--~----~
    To post to this group, send email to NavList@fer3.com
    To unsubscribe, send email to NavList-unsubscribe@fer3.com
    -~----------~----~----~----~------~----~------~--~---
    

       
    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