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
    Re: Almanacs, theory and use.
    From: Fred Hebard
    Date: 2007 Nov 21, 08:57 -0500

    the assumed position has to be fairly close to your actual position
    to work.  If your longitude is out 180 degrees, it might even be off
    180 degrees (there are two intersections of the circles of position
    on the globe).  Even if you chose the right point of intersection,
    you have to be fairly close, a few degrees.  What you can do then is
    take the newfound position as a second assumed position and rework
    the calculation.
    On Nov 21, 2007, at 5:29 AM, Isonomia wrote:
    > Thanks again for all the links.
    > I've worked out how it is possible to use a simple table to calculate
    > azimuth.
    > My confusion came about because I read that the "assumed position" was
    > an arbitrary position, however given that a 3 significant digit cosine
    > take one page in a log table, then for an arbitrary two angle sum, one
    > is talking about hundreds of pages for a 4 significant figure double
    > angle table.
    > From what I understand so far, the assumed position isn't arbitrary,
    > but is a whole number of degrees away from the geographic position,
    > making the tables much much smaller (by some 3600x)
    > To be in simply, I was misled into believing the assumed position was
    > something to do with the desired outcome, rather than a simplification
    > of the calculation!
    > >
    To post to this group, send email to NavList@fer3.com
    To unsubscribe, send email to NavList-unsubscribe@fer3.com

    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