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    Re: Getting ready for a spring demo...
    From: Frank Reed
    Date: 2013 Dec 30, 08:23 -0800

    Hi Greg,

    You wrote: "Sorry for all the hub-bub; I was working in degrees and not radians I just never hit the TAN key *ARG* I thought I did but didn't"

    Well, yes. :)

    But if you learn the 3438 trick, then this will never be an issue EVER. Using a tangent function to solve a triangle with an angle smaller than one degree is like using a sledgehammer to crack eggs. It works... but...

    If you can't wrap your brain around the idea of not using trig functions for small triangles, then think of this instead as a "quality control" or "error checking" trick. The sines and tangents of small angles are both nearly equal to the angle in minutes of arc divided by 3438 (this is extremely accurate for angles smaller than one degree). So if you punch up the sine of 30' on your calculator, you should expect a result a bit less than 0.01. Why? Because 30/3438 is just under 1%. Try it out: ask your calculator for the sine (or tangent) of 30'. Then calculate 30/3438. How do they compare?

    Now back to your project:
    I'm surprised Randall Morrow hasn't spoken up yet about your artificial horizon, though he may not be following NavList messages right now. Over the past two years he made several different artificial horizons and found all sorts of interesting options for levels and other tricks. Here is an index of his messages on this topic:
    http://www.fer3.com/arc/sort2.aspx?y=201109&y2=201312&subject=horizon&author=morrow

    -FER
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