What is the use of a cross staff?

In navigation the instrument is also called a cross-staff and was used to determine angles, for instance the angle between the horizon and Polaris or the sun to determine a vessel’s latitude, or the angle between the top and bottom of an object to determine the distance to said object if its height is known, or the …

How did sailors use a cross-staff?

To use a cross staff, the navigator positions the end of the pole on the cheek just below the eye, and picks two objects to sight, such as the horizon and the sun. He or she slides the transom along the staff until one end lines up with one object, and the opposite end lines up with the other object.

What is a cross-staff and back staff?

A very early navigational instrument, the cross staff was widely used among surveyors and astronomers. It was not until the 1500s, after it was developed further, that it started to be used at sea. The name is derived from its cross shape.

What is the meaning of cross-staff?

Definition of cross-staff



: an instrument formerly used at sea for taking the altitude of a celestial body.

Who created the cross-staff?

Levi ben Gerson

The cross-staff was an observing tool developed by Levi ben Gerson (1288-1344). It allowed a straightforward measurement of the angular separation of two celestial objects, or the angular diameter of a single object.

How do you make a cross-staff?

Video quote: The cross staff is a simple with a pointed end. So that it can easily be set into the ground on. Its top there is a square block of wood. There is a pair of grooves on the block.

How many faces does a cross-staff have?

Answer: The French Cross Staff has Eight Faces on it. Each Face is connected to the other with a 45 Degree Angle.

Which cross-staff is more accurate?

An optical square is used for the same purpose as the cross-staff, but it is more accurate.

How many types of cross-staff are there?

three types

How many types of cross staff are available? Explanation: The three types are open cross staff, French cross staff and adjustable cross staff. Open cross staff has two vertical, opposite slits.