Welcome to the NavList Message Boards.

NavList:

A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Position-Finding

Compose Your Message

Message:αβγ
Message:abc
Add Images & Files
    or...
    Re: Letcher's Lunars Math
    From: Frank Reed CT
    Date: 2004 May 31, 22:23 EDT
    Last week, George H wrote:
    "Unfortunately, that table handles "distances", angles across the sky, up to 90deg, and no further. I think there would have been no problem in extending the table to 120deg, but
    Letcher didn't do that. So once a user gets to correcting for refraction, with a lunar distance greater than 90, he is outside the limits covered by table 15.2. What does he do, then? Thoughtfully, in the caption to that table 15.2, Letcher has provided the expressions that it is based on."

    Wow. OK, thanks. Now I see what you were getting at. That strikes me as a very trivial issue considering --as you note here-- that the equation to calculate any value is right there in the caption of the table. The method in Letcher is correct just as it is (except for the potential errors in clearing the distance of up to a few tenths of a minute of arc which Letcher himself describes in the book).

    Frank R
    [ ] Mystic, Connecticut
    [X] Chicago, Illinois
    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)