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: John Wesley Powell River History Museum
    From: Robin Stuart
    Date: 2021 Oct 30, 09:33 -0700

    Ken,


            Thanks for posting this more realistic picture. I assume that is the mercury flask that can be seen on the ground to his left. The artificial horizon seems to have glass side walls which is probably not correct.


    I have to take back my earlier statement about the problems with the sextant in the sculpture, "The telescope is horizontal but the arc is not symmetrical about the vertical." Looking at a number of examples it appears that modern sextants tend to have the telescope and horizon mirror mounted at the same distance from the central axis. This means that when the sextant is sighted horizotally the arc is symmetrical about the vertical and the instrument is balanced. In a number of earlier versions I have seen the horizon mirror is mounted further from the axis than the telescope. This means that arc extends further forward than backward when held horizontally. This just how it appears in the sculpture and in the picture,


    Robin Stuart

       
    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