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: Whole Horizon Mirror vs. Split Horizon Mirror
    From: Ken Gebhart
    Date: 2015 Nov 25, 14:52 -0600
    I believe I was the origin of the pithy saying. Back in the days of doing 6 boats shows a year, and explaining the sextant and its choices to 25 people a day, you really didn't have the luxury of long winded explanations.
    On Nov 24, 2015, at 3:15 PM, Frank Reed wrote:

    Stan, you quoted from John Karl's book:
    "the whole-horizon mirror makes easy sights easier, and hard sights harder."

    Yes, indeed, that's in his book, but he's not indicating his source for that pithy summary. John Karl is quoting David Burch, apparently without credit (naughty, naughty! ...but these things happen innocently in a field like celestial navigation). Burch's version reads:
      "full-view mirrors make the easy sights easier, and the hard sights harder".
    In fact, David Burch's article on this issue forms the basis for John Karl's entire section on this topic (see below). To read Burch's original article, download volume 4 of his compilation of issues of the Navigator's Newsletter here, and go to issue 91, pages 8-9.

    At first I wasn't sure which version came first, John's or David's version of this "pithy summary". But the very next item in that issue of the Navigator's Newsletter is a notice announcing the first celestial navigation conference that I organized at Mystic Seaport back in 2006. Ken Gebhart had convinced John Karl to attend since he was still writing his book. I remember talking to John after my lunars presentation, and the book was getting close but it was not done. So that's the order: David Burch said it first.

    For everyone's further reading pleasure, here are links to the four compilations of all issues of the Navigator's Newsletter:
    Volume 1 Issues 1-31
    Volume 2 Issues 32-61
    Volume 3 Issues 62-88
    Volume 4 Issues 89-99

    Frank Reed
    Conanicut Island USA

    View and reply to this message


       
    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