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: first sextant sights
    From: Alexandre Eremenko
    Date: 2006 May 3, 11:43 -0500


    On Wed, 3 May 2006 jimattac@aol.com wrote:

    > I have posted some results I have taken
    > under excellent conditions

    Where did you post these results?

    > and found that the <0.5 claim not unreasonable and certainly
    > not if an artificial horizon is used.

    Well, of course, if the art horizon is used, one has
    to multiply the error by two, when comparing with
    ordinary shots.

    > Obviously you simply are not going to get the
    > same result with a single shot on the deck of
    > a pitching sailboat.

    Sure. These are the separate things, of different nature.
    So I am trying to analyse them SEPARATELY.
    a) small boat problems
    b) horizon problems
    c) reduction and almanac errors
    d) sextant and observer acuracy in taking sites.

    In discussing d) as a separate issue from a) and b) and c),
    I am thinking of the observations of star-star and Lunar
    distances on land under ideal conditions only. One can
    add art horizon observations to the same category.

    > Maybe with ideal conditions, lots of work on IE,
    > averaging, graphing, good knowledge of instrument
    > error and close attention to almanac data
    > and reduction method you could but this would
    > really be taxing the limits.

    That's what I am trying to do.

    > It is not founded on any analysis but,
    > I do have to believe that top end modern
    > sextants are better that what Cook

    This is not evident to me.
    I've seen the results of Cook's astronomers,
    enough of them to judge about accuracy.
    But I have seen very few modern results with best sextants
    to compare. Maybe someone will post such results?
    (I mean distances and art horizon from land).


    To post to this group, send email to NavList@fer3.com
    To unsubscribe from this group, send email to NavList-unsubscribe@fer3.com

    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