The fore-staff is composed of a square staff and three vanes o different lengths, The sides of the staff have different scales, each corresponding to one of the vanes. When observing the altitude of the sun only one vane is used. Holding one end of the st
RMID:Image ID:G15N5W
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Science History Images / Alamy Stock PhotoImage ID:
G15N5WFile size:
43.8 MB (460.3 KB Compressed download)Releases:
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3000 x 5106 px | 25.4 x 43.2 cm | 10 x 17 inches | 300dpiPhotographer:
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This image could have imperfections as it’s either historical or reportage.
The fore-staff is composed of a square staff and three vanes o different lengths, The sides of the staff have different scales, each corresponding to one of the vanes. When observing the altitude of the sun only one vane is used. Holding one end of the staff to his eye, the observer moves vane until he sees its lower end level within the horizon and the upper end in one with the sun. The altitude is read off where the cane cuts the staff.