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: Problems with AstronavPC
    From: Joel Jacobs
    Date: 2004 Feb 16, 16:29 -0500

    I may be plain dumb, but how would you know in advance that the AP is within
    or without 30NM from the intercept if you hadn't first reduced the sight
    which requires the selection of an AP. Or is this a misunderstanding of
    terms? Isn't it that the AP should be within 30 NM of the DR?
    
    Joel Jacobs
    
    ----- Original Message -----
    From: "Jim Thompson" 
    To: 
    Sent: Monday, February 16, 2004 3:32 PM
    Subject: Re: Problems with AstronavPC
    
    
    > I'm new to CN, but isn't the only reason that we try to keep the AP within
    > 30 NM of the intercept for convenience in plotting?  In theory we don't
    even
    > need an AP: with the right tools (electronic would be the only practical
    > way) we just need the GP of the Body, Azimuth to the GP, and co-altitude
    > (distance to the LOP from the GP).  In that special case, the intercept is
    > the co-altitude, which of course tends to be many hundreds or even
    thousands
    > of miles away from where we are on the celestial LOP.  All a computer
    would
    > have to do is produce data that we need to plot a short segment of the LOP
    > and the intercept on a large-scale plotting sheet; specificaly a reference
    > point on the plotting sheet, a bearing line to draw toward or away from
    that
    > point, and the distance from that point to the LOP along the bearing line.
    >
    > I know -- that "reference point" is the same concept as an AP.  But is
    there
    > any other reason why we need to select an AP relatively close to our real
    > position?
    >
    > Jim Thompson
    > jim2{at}jimthompson.net
    > www.jimthompson.net
    > Outgoing mail scanned by Norton Antivirus
    > -----------------------------------------
    >
    > > -----Original Message-----
    > > From: Navigation Mailing List
    > > [mailto:NAVIGATION-L{at}LISTSERV.WEBKAHUNA.COM]On Behalf Of Aubrey
    > > O'Callaghan
    > >
    > > I then placed my initial position nowhere near where I was. After about
    3
    > > iterations it converged to my actual position. I was quite surprised as
    I
    > > had thought that one's initial guess should be approximately where one
    is
    > > (at least within a few degrees).
    >
    
    
    

       
    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