NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Brad Morris
Date: 2013 Mar 24, 02:20 -0400
Thx Gary!
After reviewing these old posts you might choose anything between 0.8 to 1.5 for your sigma, the lower number comes from Jeremy's data and the
"The accuracy of Astronomical Observations at Sea", Journal of the Institute of Navigation, vol X, No 3, July 1957. and the
1.5 from my results.
39% of your fixes should be within one sigma,
86% within 2 sigma and 98% within 3 sigma.
gl
gl
da
--- On Sat, 3/23/13, Gary LaPook <garylapook---net> wrote:
From: Gary LaPook <garylapook---net>
Subject: [NavList] Re: The Accuracy of Astronomical Observations at Sea
To: garylapook---net
Date: Saturday, March 23, 2013, 9:55 PM
We have discussed this before Starting in September 2010 through December so look in the archives, http://www.fer3.com/arc/sort2.aspx?y=201009
. I posted my results here:
http://fer3.com/arc/m2.aspx/Accuracy-sextant-observations-sea-LaPook-sep-2010-g14008
http://fer3.com/arc/m2.aspx/Transatlantic-on-Royal-Clipper-celnav-LaPook-nov-2009-g10827
http://fer3.com/arc/m2.aspx/Accuracy-sextant-observations-sea-LaPook-sep-2010-g14025
http://fer3.com/arc/m2.aspx/Accuracy-sextant-observations-sea-LaPook-nov-2010-g14398
http://fer3.com/arc/m2.aspx/Accuracy-sextant-observations-sea-Huxtable-sep-2010-g14011
http://fer3.com/arc/img/114011.100301.pdf
http://fer3.com/arc/m2.aspx/Accuracy-sextant-observations-sea-JeremyC-sep-2010-g14020
gl
--- On Fri, 3/22/13, Brad Morris <bradley.r.morris---com> wrote:
From: Brad Morris <bradley.r.morris---com>
Subject: [NavList] Re: The Accuracy of Astronomical Observations at Sea
To: garylapook---net
Date: Friday, March 22, 2013, 12:02 PMChief Franklin
I was hoping this topic would catch your eye. It references a topic which, it is clear, you participated in!
The data from PVH Weems did seem very good (+/-0'.6 for an individual LOP), almost too good. In your experience, what could one expect to achieve with celestial in deep water? Is it +/- 3'.0 or some other value?
As an evaluator for US Navy navigation systems, you must have seen expected numbers for celestial navigation. If its possible, can you share some of those numbers with us?
I'm looking for coastal piloting and deep water celestial values.
Thanks Chief!
Brad Morris
On Mar 22, 2013 1:46 PM, "Byron Franklin" <byronink---com> wrote:Byron:Very interesting for a quick read. I never knew my accuracy while Navigating any ship at in deep water, at sea, except the sub,s.and coming in to port. I didn't think my accurcy was as good as what I saw in the artical. It is interesting to read this checks on celestial accurcy, but, not important to the sea goer. If you obtain a celestial fix at sea and it's off 3.o miles and you are observing from a ship with eye,s 16 feet and above the water the horizon is about 4.4 miles away (distance to horizon)
you should see the rocks in your line of sight. The accuracy of 0.something is not and should not be expected in deep water navigation. I evaluated and reported on new equipment for the Navy for many year, except for the sub's and close water piloting a fix off few miles were of no concern then?
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