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
    Index error adjustment...
    From: Rick Emerson
    Date: 1999 Jan 26, 11:56 EST

    Russell Sher writes:
     > Hi - With all the talk on sextants, perhaps I can squeeze in a question
     > about index error adjustment;
     > I have an instrument which has two right-angle shaped brackets for assisting
     > with index glass adjustment - With the instrument held horizontally, these
     > calibrating brackets are placed on the arc so that both the reflected and
     > true images are seen. The relative heights of these are adjusted into
     > co-incidence with the adjusting screw to give perpendicularity. When I
     > removed these brackets and eye-balled the arc directly, after performing the
     > adjustment, I noticed that there was still some error - In other words,
     > these two methods are possibly not as reliable as each other- OR is this a
     > case of parallax error, or the way which I am viewing the arc? Celestaire
     > (www.celestaire.com) market calibrating cylinders for the same purpose -
     > does anyone have any experience with these? Any comments etc.
    Without seeing what you're doing with the brackets, it's hard to
    suggest a remedy - if one's needed.  We can talk about this off-list
    if you want.
    As to Celestaire's cylinders, save your money and get a set of dice
    from a toy store.  Dice are machined to surprisingly close tolerances
    (or the results aren't random as they should be).  Made of plastic,
    they don't rust and replacement costs are minimal.  I keep a set in
    the sextant box for use as calibration tools and, if all else fails in
    reducing a sight, as decision-makers... [wink]
    S/V One With The Wind, Baba 35
    =-=  TO UNSUBSCRIBE, send this message to majordomo@XXX.XXX:     =-=
    =-=      unsubscribe navigation                                         =-=

    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