NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Cross Staff in use, 1574 image
From: Brad Morris
Date: 2009 Oct 16, 13:13 -0700
From: Brad Morris
Date: 2009 Oct 16, 13:13 -0700
Attached, please find an image from Cosmographia, Petri Apiani, of the cross staff in use. This image is consistent with the direction given in Bourne's A Regiment for the Sea, in that the user is directed to align the cross staff to the center of the sun's body. How in the world was the cross staff operator to know when he was aligned to the center?? Thus the resultant latitude would always be an estimate, say plus or minus 8 arc minutes, based upon the judgement of the operator. Perhaps in 1574, that was plenty good enough. There is plenty of discussion on our list of just what is good enough and how far we should take it. Clearly, this is not a new topic whatsoever! Best Regards Brad --~--~---------~--~----~------------~-------~--~----~ NavList message boards: www.fer3.com/arc Or post by email to: NavList@fer3.com To , email NavList+@fer3.com -~----------~----~----~----~------~----~------~--~---