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: Measuring Dip in the 18th Century
    From: Gary LaPook
    Date: 2014 Jan 1, 12:23 -0800
    I included his explanation of how he measured the maximum declination.

    gl



    From: Alexandre Eremenko <eremenko@math.purdue.edu>
    To: garylapook@pacbell.net
    Sent: Wednesday, January 1, 2014 8:42 AM
    Subject: [NavList] Re: Measuring Dip in the 18th Century


    Gary,
    
    > I have also attached the June page showing Wright's
    > determination of the Sun's maximum declination as 23� 30'
    > north while the
    > modern value is 23� 26.3' a difference of only 3.7'.
    
    Did you take into account that obliquity of the ecliptic
    decreases at the rate about 0'.7 per century?
    More precisely, 46".8 per century.
    This implies that Wright wrote it correctly.
    
    I have not read the book yet:-)
    but I assume that he was using some astronomical tables available at that
    time, or did he determine all astronomical constants himself??
    
    Alex.
    
    
     I have also included
    > Wright's explanation of how he determined the Sun's declination.
    >
    > http://en.wikipedia.org/wiki/Gregorian_calendar
    >
    > gl
    >
    > gl
    >
    > Attached File: http://fer3.com/arc/img/126089.march declination table from
    > wrights book.jpg
    >
    > Attached File: http://fer3.com/arc/img/126089.june declination from
    > wrights book.jpg
    >
    > Attached File: http://fer3.com/arc/img/126089.explanation of declination
    > determine by wright_page_1.jpg
    >
    > Attached File: http://fer3.com/arc/img/126089.explanation of declination
    > determine by wright_page_2.jpg
    >
    >
    > View and reply to this message: http://fer3.com/arc/m2.aspx?i=126089
    >
    >
    >
    >
    
    
    View and reply to this message: http://fer3.com/arc/m2.aspx?i=126097


       
    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