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
    or...
       
    Reply
    Re: Spherical earth model vs. ellipsoid
    From: Henning Umland
    Date: 1999 Mar 15, 2:43 PM

    
    Date sent:      	Mon, 15 Mar 1999 13:07:11 +0100
    From-           	Jim Manzari 
    Organization:   	am Buck
    To:             	navigation{at}ronin.com
    Subject:        	Re: [Nml] Spherical earth model vs. ellipsoid
    Send reply to:  	Jim Manzari 
    
    
    >
    > Henning,
    >
    > I was intrigued by your test.  It appears to have been well planned
    > and executed.  Thanks for posting a very interesting summary of the
    > results.
    >
    > You've expressed a doubt as to whether the method may be applied
    > elsewhere in the world.  Perhaps my experience in a similar experiment
    > might give you some food for thought.
    
    
    Jim,
    When I made my experiments, I was aware that the spirit level can
    be deflected by local anomalies of the earth's surface like ,e.g., ore
    deposits, mountains, lava plugs, etc.
    Fortunately, the area southeast of Hamburg is absolutely flat, the
    ground consists only of clay, sand, and pebbles deposited by
    glaciers, and we don't have ores and other heavy minerals here.
    I was thinking of geometric anomalies in other parts of the world,
    for the earth is not really an ellipsoid but has a rather irregular
    shape with local depressions and the like. I once saw an image
    showing the exaggerated irregularities of the earth. It looked like a
    dented apple.
    The theodolite I have is a TOPCON DT-102. It is an electronic
    model with a built-in microprocessor and digital display. Further, it
    has an electronic tilt compensator which is a very useful device
    since the legs of the tripod sometimes change their length to a
    different degree when irradiated by the sun (otherwise you would
    have to adjust the spirit level repeatedly).
    Although mostly used for surveying, theodolites are valuable
    instruments for celestial navigation as well (on land only!). Due to
    their superior precision they are the first choice when doing
    "academic" studies.
    
    Regards,
    Henning
    
    
    =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=--=-=
    =-=  TO UNSUBSCRIBE, send this message to majordomo{at}roninhouse.com:     =-=
    =-=      unsubscribe navigation                                         =-=
    =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=--=-=
    

       
    Reply
    Browse Files

    Drop Files

    NavList

    What is NavList?

    Join NavList

    Name:
    (please, no nicknames or handles)
    Email:
    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:

    Email Settings

    Posting 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