NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: How to choose among position lines?
From: Doug Royer
Date: 2003 Jun 11, 13:13 -0700
From: Doug Royer
Date: 2003 Jun 11, 13:13 -0700
Jared,you bet.I believe I understand what you're saying.Critique what I think you're saying.One takes 4 sights in a round not spaced 90* apart but each one at some degree of seperation.One then takes 2 sights of the same body at each Zn and works the plot the same way as if takeing 8 sights evenly spaced. As for the spaceing of Zn's by divideing the number into 360*,it's a decient proceedure used insure a workable Zn spread.I've encountered the same thing on study material.I believe it is used to teach the student reduction mechanics but is not very practical in real use.Even on a starry cloudless night why would a person spend the time to do a 5,6,7,8 or an infinite number of sights in a round when a 1 or 2 sight round combined with an advance or a maximum 3 to 4 sight round would give a very workable MPP.It would,in my opinion,be smarter to do a number of smaller number sight rounds throughout the day instead of all at once. -----Original Message----- From: Jared Sherman [mailto:jared.sherman@VERIZON.NET] Sent: Wednesday, June 11, 2003 11:49 To: NAVIGATION-L@LISTSERV.WEBKAHUNA.COM Subject: Re: How to choose among position lines? Doug- I wonder, if perhaps dividing the number of sites into 360 degrees and spreading them out evenly is counterproductive? Consider that case of 8 sights. If I plot them evenly about I'll get one smudge on the chart. But if I plot two sights each at 4 positions...The difference between the two lines from any one direction will also tell me that I have an error of at least that amount. Wouldn't that information be just as useful? Aside from star sights at night on a cloudless sea, who would have the luxury to take 8 sightings in equidistant directions anyway?