NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Horizontal Sextant angles plot.
From: Lu Abel
Date: 2012 Apr 5, 11:00 -0700
From: Lu Abel
Date: 2012 Apr 5, 11:00 -0700
And don't forget that a Navy ship is a whole lot more stable of a platform than a bouncing small boat....
On my boat, even with the best of hand-bearing compasses, I am lucky to get within 5 degrees.
Don't know if they still make it, but AutoHelm used to make an electronic hand bearing compass where you could click a button and it would remember the bearing; theoretically you could click five of them or so and average them to get a reasonably accurate bearing.
From: Alexandre E Eremenko <eremenko@math.purdue.edu>
To: NavList@fer3.com
Sent: Thursday, April 5, 2012 8:54 AM
Subject: [NavList] Re: Horizontal Sextant angles plot.
Byron,
Thanks for this info.
I did not know that there are compasses with 1/10 degree accuracy.
Curious to see one (or a description).
Alex
On Thu, 5 Apr 2012, Byron Franklin wrote:
>
> Sextant Angles are accurate, but compass bearings are accurate also.The US Navy uses the compass because with a port and Stabd bearing taker you can cover 360 degrees of the Navaids available,also the time to take bearings are only seconds for three bearings. The scope for bearings are near one tenth of degree.
> With no compass error fixes are taken every three minutes and plotted. See Franklin Ploting Technique. the same rules apply to compass and sextant for accuracy or circle running, If the the middle Navaid is farther and near the circle running on each navaid and observer the fix is undetermible. This can be seem on the chart by the Navigator and he must stay away from this situation.
> The 3 arm is a nice tool to have but, the same task can be done with tables or a small plastic compass in degrees.see 25 Nov 2010.
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