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Re: Plotting vs calculating Position
From: Lu Abel
Date: 2015 Jul 30, 20:18 +0000

Bob:

If you remember what the sine and cosine curves look like, the values for angles between 90 and 180 are very easily related to values less than 90.

For X between 90 and 180,

Sin (X) = Sin (180-X)

Cos (X) = - Cos (180-X)

From: Bob Goethe <NoReply_Goethe@fer3.com>
To: luabel@ymail.com
Sent: Thursday, July 30, 2015 1:11 PM
Subject: [NavList] Re: Plotting vs calculating Position

I am intrigued by the equation to correct for motion-of-observer:
ΔHo = (SΔt/60)*cos(Zn-C)
Is it feasible to calculate this using a slide rule where (Zn-C) is greater than 90°? I have never done sines/consines on a slide rule where any of the angles were larger than 90°.
Bob

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