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: Mirror problem
    From: Alexandre Eremenko
    Date: 2006 May 5, 14:27 -0400

    Dear Frank,
    In your message Thu May 04 2006 - 21:57:26 EDT
    you wrote:
    >Since your instrument passed certification by not one, but two,
    >recognized experts I doubt your mirrors are the problem.
    I have some doubts on "certification by recognized experts",
    as expressed in
    my recent message on Sextant certificates
    Thu May 04 2006 - 13:05:50 EDT,
    Using this opportunity, I correct the addresses of
    the two pictures mentioned in that message, they are
    The reasons of my doubts are:
    1) C+P certificate says "free from errors for practical use"
    and Freiberger's certificate shows 13" arc error at one place.
    I agree that 13" is OK for "practical use" but not for the
    Lunar and star distances that I am doing.
    And I guarantee that nothing has happened to the sextant
    between these two certifications.
    2) My multiple attempts to check the arc myself using star
    distances give quite consistent results that DISAGREE with BOTH
    certificates by 0'.7 to 0'.8. This is of course essential, even
    for "practical use". But certainly I cannot be 100% sure
    in these results because I might just be a poor observer,
    or some other effect than the deformation of the arc could
    explain this.

    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