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    Re: Longhand Sight Reduction
    From: Greg Rudzinski
    Date: 2014 Jun 27, 20:01 -0700


    The L-d subtraction is trouble. What I do when needed is subtract a degree and then add 60 minutes to the minute value.


    42° 3' - 23° 17' is the same as 41° 63' - 23° 17' which can now be done mentally to get 18° 46'

    Division and subtraction is where I need to be careful. Pulling the wrong value out of an almanac or table happens more frequently than it should . 

    Greg Rudzinski

    Re: Longhand Sight Reduction
    From: Hanno Ix
    Date: 2014 Jun 27, 17:04 -0700

    I can see where you are coming from. Of course, though, 
    this is a matter of personal preference.
    I like to do CelNav calculations by hand. I admit I am
    a purist in this regard. Most importantly, it keeps my old brain 
    lubricated. Also, my logic tells me if I used a calculator for CelNav 
    I might as well use one with built-in GPS and be done.
    When I analyzed some time ago where I make mistakes most
    often, it was multi-digit multiplications and sexagesimal arithmetic.
    Ridiculous but true: 23 deg 52 min + 14deg 12 min could make me
    insecure about my result. And, horror,  L+D and L- D occurs in Doniol.
    For multiplication I use only Vedic anymore. Since I started using
    Vedic and arcmin only I end up with much less errors. 

    Less, I say, not none :(
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