# NavList:

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

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Re: Cocked hats, again.
From: Fred Hebard
Date: 2007 Mar 15, 07:30 -0400

```Things like anomalous dip, fuzzy horizons, hazy sky, condition of the
sextant operator, etc, will cause sigma to vary.

On Mar 15, 2007, at 12:22 AM, Gary J. LaPook wrote:

>
> Gary LaPook wrote:
>
> Indeed I do assume that the sigma is the same for large and small
> triangles. Sigma is based on the method of observation and the
> randomness of the factors that effect the observations, waves, hazy
> horizon, etc.
> Sometimes the random errors have the same sign and you get a large
> triangle and sometimes the signs are different and you get a smaller
> triangle, this is the nature of random errors even though sigma
> remains
> the same.
>
> Fred Hebard wrote:
>
>> Gary,
>>
>> The size of the Gaussian bell curve, or whatever curve, around each
>> position line wouldn't affect the probability of being on one side or
>> another; as long as the curve is symmetrical the probability would
>> still be one half.  The triangle is merely at the intersection of the
>> lines; another of our assumptions are that the errors for each line
>> are independent (and, for some calculations, equal).  A small
>> triangle suggests that sigma is small for each line, and a large
>> triangle that sigma is large.  You appear to be assuming sigma is the
>> same size for different sized triangles.
>>
>>
>
>
> >

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