Backstaff

Definition:

• (n.) An instrument formerly used for taking the altitude of the heavenly bodies, but now superseded by the quadrant and sextant; -- so called because the observer turned his back to the body observed.

Compare backstaff with other words:

backstaff vs. calculating

backstaff vs. latitude

backstaff vs. sun

altitude vs. backstaff

backstaff vs. measuring

backstaff vs. instrument