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: Real accuracy of the method of lunar distances
    From: Fred Hebard
    Date: 2004 Jan 14, 18:29 -0500

    I responded earlier today to Jared's message, but only to him, for some
    reason.  It didn't help that I recarved my HD today.  But I did mess up
    my reply so this is a chance to set it straight.
    
    Fred
    
    
    >  those times when the Apparent
    > Moon is moving more slowly? Those times are when the Moon is highest
    > in the
    > sky. If you can answer that question, you have settled the argument.>
    > [Geo. Huxtable]
    >
    >
    > Ah, a crux. I'm afraid even I may be understanding this thanks to all
    > the patient re-explanations.
    >
    >
    > For the sake of simplicity, I think we can for a moment ignore the
    > question of whether/when the moon appears to move more rapidly against
    > the stars, and stick to the crux of things.
    >
    >
    > Perhaps we could perform a simple exercise here:
    >
    >
    > Assume that I take a lunar distance measurement at 5:30AM. And then
    > again at midnight.
    > 1-How long does it take me to take the lunar, i.e. to measure the
    > distance from the moon to the other body?
    > Is that "instantaneous" observation affected by the speed of the
    > moon's motion?
    
    no
    
    >
    > 2-Am I doing anything else, which is not "instantaneous", which will
    > be affected by the "speed" of the moon?
    
    no
    
    > 3-Bottom line time. Perform the above observations and timings,
    > assuming both the fastest and slowest "speed" of the moon for the
    > readings when the moon is overhead, and on the horizon. Clear the
    > lunars from both times. (Or all three, to use both horizons.) Are the
    > results ANY different, allowing for a different speed of the moon?
    
    no
    
    > And if #3 seems unclear, that's because I'm not familiar with the
    > mechanics of clearing a lunar, so please feel free to re-structure the
    > experiment allowing for the realities of the process. Theories are
    > fine, but what are the actual numbers? How does the presumed change in
    > lunar "speed" affect readings, if it does at all? To what amount of
    > time? Five seconds? One? Just what IS the magnitude of error that we
    > are chasing here?
    
    zero
    
    
    

       
    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