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: Traditional navigation by slide rule
    From: Gary LaPook
    Date: 2016 Jan 21, 06:15 +0000
    Cool idea and thw trig scales are marked in degrees andd MINUTES.


    From: Hewitt Schlereth <NoReply_Schlereth@fer3.com>
    To: garylapook@pacbell.net
    Sent: Wednesday, January 20, 2016 6:27 PM
    Subject: [NavList] Re: Traditional navigation by slide rule


    Bob, here are photos of a cel Nav slide rule I made by putting the slide from K&E 4070–3 into the body of a a 4090–3. As you see, the 4090-3 has the trig on its body; the 4070-3 has them on its slide. Really saves steps when solving the sin/cos formula for Hc.


    PS I'd surely buy a rule made specifically for celestial.

    On Jan 20, 2016, at 12:22 PM, Bob Goethe <NoReply_Goethe@fer3.com> wrote:

    Great idea, Gary, but easier said than done.  The only really good image of deg/min scale I found today was from the Podmore book, where he illustrated the Academy Duplex 504. The Academy 504 has digits marking each degree between 10° and 20° on the tangent scale.  When I compared that to the decimal illustration I had, the deg/min model looked vastly more busy to me.  I thought that would skew a collective assessment unfairly in the direction of decimal degrees.
    I went and manually deleted the numbers from my screen capture, to try and get closer to oranges and oranges.  But the only way to really do this well is to get control of the tangent function with VBA and Corel (which I have yet to do), and produce the scales as you wish.  
    Failing that, the best one can do is to compare oranges, so to speak, with other similar-style citrus fruit.   If we are reduced to using images we came up with in Google searches, and imagining what it could look like...well, we can all engage in that sort of imaginative exercise.  I am not the only one who can set the visual parameters of the comparison we use as a discussion point.

    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