NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Ted Gerrard
Date: 2007 Nov 12, 15:20 -0000
Nicolas wrote
....what I would like to know is if it was explicitly written down that those
7 observations were
done using back-staffs.
Reply from Ted
As I said before, I have absolutely no idea, or at least no
hard evidence that any of the navigators in the Shovell fleet specifically used
back-staffs to take any of those 7 noon sights on that fateful day. However most
certainly at least one ship in the fleet carried _quadrants_ ... Sir William
Jumper, (a member of the Paramore Court Martial sitting in judgement on Edmond
Halley's first officer, Edward Harrison) captain of the 70 gun Lennox.
The term used by Jumper is discussed by May (Naval compasses in 1707, p409) who was of the opinion that Jumper may have been referring to a Davis Quadrant or Backstaff.
Edward Harrison, for all his faults a brilliant navigator and certainly as good as any in the RN bar Halley prior to his dismissal by Shovell), made very good use of a back-staff fitted with a Flamsteed lens (invented by Robert Hooke) during the first Paramore expedition in 1698.
Ted Gerrard
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