NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Sumner Line using Ex-meridians
From: Peter Monta
Date: 2013 Nov 18, 08:02 -0800
From: Peter Monta
Date: 2013 Nov 18, 08:02 -0800
Today impossible at sea!. There is no accurate enough azimuth available.
Were gyrocompasses ever used for this purpose? One could project a gyrocompass-referenced virtual marker onto the horizon (suitably far from the point below the Sun, say 90 degrees or so), then take distances to the Sun with a sextant to obtain the solar azimuth. This would have to be pretty accurate to upgrade a conventional line of position to a fix, though (few arcminutes).
Cheers,
Peter
Peter
ps: after searching, I find this has already been suggested on NavList back in 2009 by George Huxtable:
http://fer3.com/arc/m2.aspx?i=108076&y=200904
http://fer3.com/arc/m2.aspx?i=108076&y=200904
Truly there is nothing new under the sun (pun intended). So how good are gyrocompasses for accuracy, both modern ones and ones available in, say, 1930?