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    Re: Traditional navigation by slide rule
    From: Gary LaPook
    Date: 2016 Jan 19, 13:35 -0800

    I don't know why the photo of the K&E 4080-3 didn't come through but here it is.


    Re: Traditional navigation by slide rule
    From: Gary LaPook
    Date: 2016 Jan 19, 21:05 +0000

    I have been having a  discussion with Bob and am forwarding one of my emails to him that have photos of the scales of both types of slide rules. That example looked at 76 degrees on the tan scale. You can see that the tan scale, at that point, has 10 divisions on the Pickett rule and 12 divisions on the K&E 4080-3 rule, each division on the K&E is 5 minutes while on the Pickett they are 6 minutes, not a significant difference in precision for the computation. But using the decimal rule means converting from minutes to decimals and then back into minutes during the computation, extra work and chances for errors. So, until the Nautical Almanac publishes its data in decimal degrees, and until all of our charts are republished with degrees of latitude and longitude divided into decimals instead of the current minutes, it will make more sense to use a slide rule marked in minutes, like the K&E 4080-3 than in decimals. 



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