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: Proportional logs, etc.
    From: Jan Kalivoda
    Date: 2004 Aug 25, 23:47 +0200

    Dear Henry,
    Thanks for further details. Your table set is extremely interesting as another 
    method from the golden era of lunars that wasn't mentioned in the literature, 
    according to my reading.
    I cannot say that I understand anything from your data better than you. I have only questions:
    There should be items for small values of the difference (parallax - 
    refraction) in the Moon table, too - for her altitudes near the zenith, isn' 
    it? Yes, above 87 degs of altitude, maybe they are dropped from the table. 
    But if not, do they conform to the values found by adding the traditional 
    proplog of the difference (parallax - refraction) with logs of sin of 30 degs 
    and cos of altitude or with the values of the Sun table?
    And for the Sun table: I take your table value for 30 degs of the apparent 
    altitude, i.e. 1.7115. If subtracting 9.6990 for log sine 30 and 9.9375 for 
    log cos 30, we obtain 2.075 as the proplog of 1' 30". This corresponds to the 
    number 118.85. And if you multiply it by 90 secs, you obtain 10696 secs as 
    the basis of these proplogs, instead of common 10800 secs. Are the adjacent 
    table values (under 2 min 50 sec of the altitude correction) conforming to 
    this result? For greater values of difference (parallax - refraction)  this 
    tiny difference of cca 104 secs for the basis can disappear in computing 
    proplogs to 4 places.
    And what about the stars table? Whether and how do differ its values from the Sun table?
    I wish you much luck with Mr. Arnold. Yours,
    Jan Kalivoda

    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