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
    Name or NavList Code:
    Email:
       
    Reply
    Sextant mirror stability
    From: Fred Hebard
    Date: 2004 Oct 13, 23:31 -0400

    I haven't studied the following experimentally, but it seems to me that
    sextant mirrors take a while to "settle down" after they are removed
    for cleaning, etc.  It also seems better not to adjust them if there is
    no side error or failure of index mirror perpendicularity, as long as
    the index error is a reasonably small number, such as under one or two
    minutes of arc.  "The Sextant Handbook" also cautions against
    over-adjustment.  I wonder what other's feelings, experience, etc are
    about this.
    
    Fred
    
    On Oct 13, 2004, at 8:08 PM, Alexandre Eremenko wrote:
    
    > Lisa:
    >
    > On Thu, 14 Oct 2004, Lisa Fiene wrote:
    >
    >> As I have interpreted it, the screw on the horizon mirror that is
    >> closest to the frame is for correcting Index Error, the screw which is
    >> furthest from the frame is for Side Error (shear).
    >
    > I understood it in the same way.
    > So far, I don't know what my Index Error is, but know it is
    > small: all star tests show exact 0 or sometimes -0.1'.
    > But the Sun tests show -0.2' to -0.3'.
    > So I never touched this screw.
    >
    >> Will look at the perpendicularity thread,
    >> although I did not find any
    >> difficulty with the adjustment of the index mirror.
    >
    > Some of my messages earlier in this thread were
    > incorrect: having experience only with SNO-T I generalized it
    > to all sextants.
    >
    > Alex.
    >
    
    
    

       
    Reply
    Browse Files

    Drop Files

    NavList

    What is NavList?

    Get a NavList ID Code

    Name:
    (please, no nicknames or handles)
    Email:
    Do you want to receive all group messages by email?
    Yes No

    A NavList ID Code guarantees your identity in NavList posts and allows faster posting of messages.

    Retrieve a NavList ID Code

    Enter the email address associated with your NavList messages. Your NavList code will be emailed to you immediately.
    Email:

    Email Settings

    NavList ID 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