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
    Name or NavList Code:
    Email:
       
    Reply
    Flat Bygrave alternative configuration
    From: Robin Stuart
    Date: 2014 Mar 9, 12:25 -0700

    Gary Lapook’s innovation of the Flat Bygrave uses a double copy of the cotangent scale so that you can always find the angle you are looking for without running off the edge. For reference I attach scales that are a close copy the ones Gary has produced and made available at https://sites.google.com/site/fredienoonan/other-flight-navigation-information/modern-bygrave-slide-rule

    When it comes to Bygrave scales longer is better but doubling the cotangent scale doesn’t allow for optimal use of the available real estate on paper. I would therefore like to suggest an alternative configuration. When using a standard straight slide rule and the number you are seeking falls over the edge of the scale you move the slide by one scale length in the opposite direction. This operation has its analogue in the alternative Flat Bygrave attached here. The cotangent scale is no longer doubled and two pointers have been added to the cosine scale indicating the location of 0° and where 0° would lie if the scale were continued by one row down. Now if after lining up the 0° mark on the cosine scale the angle seeking falls off the scale, simply use the other pointer.

    The scales in this alternative version are roughly twice as long as in the original and would allow for a inserting a greater number of tick marks for improved reading accuracy before the scales become too busy. In this version however I have kept the same number of tick marks and labels as the original.

    Robin Stuart

    ----------------------------------------------------------------
    NavList message boards and member settings: www.fer3.com/NavList
    Members may optionally receive posts by email.
    To cancel email delivery, send a message to NoMail[at]fer3.com
    ----------------------------------------------------------------

    File:

      

    File:

      

       
    Reply
    Browse Files

    Drop Files

    NavList

    What is NavList?

    Get a NavList ID Code

    Name:
    (please, no nicknames or handles)
    Email:
    Do you want to receive all group messages by email?
    Yes No

    A NavList ID Code guarantees your identity in NavList posts and allows faster posting of messages.

    Retrieve a NavList ID Code

    Enter the email address associated with your NavList messages. Your NavList code will be emailed to you immediately.
    Email:

    Email Settings

    NavList ID 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