What is a back staff?

The backstaff is a navigational instrument that was used to measure the altitude of a celestial body, in particular the sun or moon. When observing the sun, users kept the sun to their back (hence the name) and observed the shadow cast by the upper vane on a horizon vane. read more

A major problem in using the Cross-Staff was in having to look at the sun. This led to blindness or at least damaged eyesight for navigators. To solve the problem, John Davis (sometimes spelled “Davies”) invented the Back Staff in 1594 (published description–1595) that used the shadow of the sun instead of the direct view of the sun to obtain the altitude. read more

A back staff is a navigational instrument that was used to measurethe altitude of a celestial body, in particular the sun or moon.When The name came from the fact that users kept the sun to theirback and observed the shadow cast by the upper vane on a horizonvane. read more