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    Re: Traditional navigation by slide rule
    From: Hewitt Schlereth
    Date: 2016 Jan 20, 17:21 -0800
    image2.jpeg


    image1.jpeg
    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.

    Hewitt

    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.

    Bob

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