# NavList:

## A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding

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Re: Bowditch Table 9
From: Herbert Prinz
Date: 2002 Apr 11, 17:49 +0000

```Hello Martin,

Welcome to the list.

> "Angle" runs from -4 minutes (a puzzle in itself) to +30 degrees;
>

That's the easy one. The angle has to be corrected for dip by which it can
become negative.

>
> The formula given in my 1981 Bowditch is
>
> Distance = sqrt (
>        ((tan A)/0.0002419)**2
>    +  (H-h)/0.7349
>     -  (tan A)/0.002419
> )
>

I can't answer this. Obviously, the formula is severely garbled. Ignoring dip
and refraction completely, but using some common sense, we have d = (H-h) / tan
A, or if you like this better, d = (H-h) * cot A.  How one gets from here to
what Bowditch has by applying correction for refraction is totally beyond me.

Keep up the good work. 8000 more and you will beat Bowditch. (He claimed to
have found that many errors in Moore.)

Best regards

Herbert Prinz

```
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