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: Persistence and demise of Lunars
    From: Bruce Cutting
    Date: 2017 Dec 11, 11:10 -0700

    I've been following posts relevant to lunars and as a rank newbie have a
    question.
    
    I've seen comments about lunar distance tables.  I'm wondering if any
    tables (other than the standard almanac) are needed.  My understanding is
    that you need tow bodies (likely the moon and the sun, but that other
    bodies can be substituted for the sun).  You need a fair guess at the
    observing latitude, date, and time, then use an iterative process to get
    actual La and Lo.
    
    I've heard it goes as follows:
    1) measure the distance between moon and body (usually limb closest to the
    sun or selected body)
    2) measure the altitude of both bodies
    3) Use the altitude of the Sun (or other body) and latitude to improve
    guess at time.
    4) using the guessed at time compute GP and altitude of both bodies and
    the expected lunar distance
    5) Iterate on the process until it converges.
    
    So the questions are:
    1) What tables are needed (if any)
    2) Where can I get more information
    3) Is a sextant accurate to minutes and seconds good enough to get
    reasonable results?
    
    Thanks in advance for help.
    
    > Another irony was that when the survivors stumbled across uninhabited
    > Henderson Island halfway through their voyage, they were a mere 100 miles
    > from a thriving English-speaking colony.  Their copy of Bowditch was not
    > up
    > to date.  Six years earlier, two British frigates had rediscovered
    > Pitcairn
    > Island, home of the descendants of the Bounty mutineers.  The information
    > had yet to filter back to America and make it into Bowditch.
    >
    >
    > Don Seltzer
    >
    >
    > View and reply to this message:
    > http://fer3.com/arc/m2.aspx/Persistence-demise-Lunars-Seltzer-dec-2017-g40877
    
    
    

       
    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