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
    Re: SNO-T tests
    From: Alexandre Eremenko
    Date: 2005 Dec 10, 12:04 -0500

    Dear Frank,
    
    > No, I haven't yet.
    
    Tell us the results when you do.
    
    > I think the method works  despite the parallax issue.
    > The only assumption is
    > that the measured angles  should be increasing linearly.
    
    It is exactly this assumption I had doubt about.
    
    > The fact that the
    > pattern repeats with a one  degree period over two full
    > degrees of measurement
    > gives me some confidence that  this technique
    > is measuring something involving
    > micrometer error. What else  could produce such cyclic behavior?
    
    That's a strong argument. I will be totally convinced when you measure
    another sextant which will not show the sinusoid pattern.
    
    I made a try yesterday, but instead of the expected sinusoid pattern
    I obtain something which looks more like "white noise".
    The interval between the lines was 2.3' and I made one full turn.
    The distance was approx 16 feet, and the mean quadratic deviation
    of the measurements was 0.17'. But there was nothing resembling a
    sinusoid pattern.
    
    > Looking at all those lines and their  reflected images through the sextant
    > drove me nuts so I switched to the "one  line above - one line below"
    
    I found the most convenient pattern 1 line above and 10 below
    and I have three pictures, 30 lines total.
    But it is definitely important that that "one line" is in exactly
    the same position on all pictures.
    
    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