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    Re: Traditional navigation by slide rule
    From: Tony Oz
    Date: 2016 Nov 23, 08:16 -0800

    Dear Bob,

    I'm studying The Lore of Sliding The Rule. :)

    The Lore teaches us to do the calculations with as few movements as possible. For this the rules usually feature the I-scale which allows for three-operands multiplication with as little as just two cursor's movements and one slider's movement inbetween.

    Because in the background the formulas are like that:

    • Hc = asin[ sin(LatEP)·sin(Dec) + cos(LatEP)·cos(Dec)·cos(LHA) ]
    • Zc = atan[ cos(Dec)·sin(LHA) / { cos(LatEP)·sin(Dec) - sin(LatEP)·cos(Dec)·cos(LHA) } ]

    I think it could be usefull to have one of trig scales in two versions: a regular and an inversed. Looks like it should be the cos(x) scale.

    What do you think? What do The Lore gurus think?

    Regards,

    Tony

       
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