A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Lars Bergman
Date: 2017 Mar 30, 13:28 -0700
Robin, now I understand how you got those fifteen seconds of time, thanks. I have always believed that a one knot speed in north/south, whether of the ship or the sun, is of no real importance; but now I realize that this belief is valid for latitude determination only. When it comes to longitude determination its influence is of more significance.
Reworking the sights, using the mid five ones for latitude, using ex-meridian, I get 41°27.3'; and using the first and last one for longitude, I find the average 71°27.5'. Sights 2, 8 and 9 are not used in this case, having a too large (magnitude) hour angle to be comfortably used in ex-meridian, and a too small one to be used for longitude.
These results are worked by hand, with log tables (and nat hav for ex-meridian).