# NavList:

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

**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. >> >> > > > > --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to NavList@fer3.com To unsubscribe, send email to NavList-unsubscribe@fer3.com -~----------~----~----~----~------~----~------~--~---