What is the cross staff?
Cross staff is a mechanical device used to measure an angle between two objects. Historically, the cross staff was greatly used in navigation to help the sailors orient themselves, and it was also studied by astronomers with the sky and inspectors who wanted to be able to make accurate measurements. It seems that this device was first invented by the Chinese, and Europeans began to use it around the 14th century; Like many devices, it was probably invented independently of several different places, which means that several people and nations are likely to deserve credit. Many cross crews have a set of transoms so that people can choose a length that would be more suitable; This allows the staff itself to be relatively short, which makes it easier and more comfortable.
For the use of cross staff, the navigator places the end of the pole on the face just below the eye and selects two objects for sight such as horizon and sun. He oro She slips the transom along the cross staff to one end with one object and the opposite end line with the other object. Although it sounds simple, it is actually quite complicated, because the user has to look in two directions at the same time without allowing employees of the cross to slip or fluctuate, and it can be even harder on board the swaying ship.
As soon as the transom is in position, the transom -covered designation indicates an angle between two objects that can be used to calculate the geographic width and to collect further information. One of the big disadvantages of using the cross staff is to look directly at the sun for observation during the day; Later models of the device contain filters that allow meadows to look more convenient. In addition, the cover could cover observations at night using different stars or observations during the day in a very heavy cloud area, which could mean that people could be forced to go for several days without taking a navigation location, whichIt makes it difficult to stay on the course.
Cross Staffs are sometimes used in classroom exercises to introduce students to mathematics for cross personnel or the history of navigation. Since then, these devices have been replaced by global positioning satellites and other navigation devices that are highly accurate and very easy to use.