Welcome to the NavList Message Boards.


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

Compose Your Message

Add Images & Files
    Re: sextant precision.
    From: Geoffrey Kolbe
    Date: 2005 Jun 20, 10:11 -0700

    >At the point where you have set aside the welder's glass, and swung in the
    >dense shade in the index-mirror view, you still have the full brilliance of
    >the Sun in the horizon-mirror view. Unless you introduce a similarly dense
    >shade into that direct view, your eye will be quite unable to take it. But
    >if you do that, you are measuring, not the error of the upper shade, but
    >the combined error of two shades (just as Lecky described), which was NOT
    >the object of the exercise.
    George, are you able to remove the index mirror shade and rotate it  - even
    using plasticene or some other jury rig to hold it in place while you see
    if the IC has shifted....?
    Geoffrey Kolbe

    Browse Files

    Drop Files


    What is NavList?

    Join NavList

    (please, no nicknames or handles)
    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 Settings

    Posting Code:

    Custom Index

    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