Backstaff (jan 1, 1594 – jan 1, 1750)

Description:

The backstaff was navigational tool that measured altitude using the sun, backstaff made taking measurements possible without having to look directly at the sun. To use the backstaff, the navigator with his back to the sun, holds the instrument in front of his and places it on his shoulder. To find the altitude, the navigator would move the vanes along the arcs, and view the horizon through a small slit. They would move the shadow vane on the smaller arc until the edge of the vane casts a shadow on the slit of the horizon vane. While doing this, the navigator would also look through a peephole in the vane on the larger arc and through a slit in the horizon vane to view the horizon. The backstaff was created by John Davis, and it lasted to 1594CE-1750CE.

Added to timeline:

Date: