# NavList:

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

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Re: Summary of Bowditch Table 15
From: Bill B
Date: 2005 Jan 26, 18:19 -0500

```Jim

Regarding the table 15 formula I wrote:

> How the formula works I leave to the math whizzes.  Clues are we see the
> square root of H-h/0.7349, which would equal H-h * 1.36.  Pretty close to
> geographical range and horizon constant of 1.169 or 1.17.  We also see
> tangents of the angle, and they are divided by 0.0002419.  The same as
> multiplying by  approx. 4134. That number looks suspiciously close to the
> Earth's radius.  We also play with the affect of the "hump" expressed as an
> angle by subtracting dip.  But there are no old bold empiricists, so I'll
> quit there ;-)

Giving it more thought, the tangent is the ratio between the height of
object and distance (opposite over adjacent).  Perhaps the x/0.0002419 or x
* 4134 (a nautical mile in feet adjusted for refraction) converts the answer
to nautical miles?

Bill

```
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