What is Alidade?

Alidade is an ancient measuring instrument that uses a line of observation to determine the position characteristics of a remote object in relation to the observer. The application of information obtained by this device was and continues to be as different as human ingenuity. In its most basic, it is simply a straight edge that can be rotated along a scale of any known or defined selection. One end of the straight edge represents the observer; The other end is moved to look at the object. The scale is read as a measurement of their relationship.

timely alidades' designs dealt with two basic characteristics of its use. In order to improve its visual accuracy, the flat edge is mounted flat and at each end the point-to-point is built as a perpendicular blade. The range proposals included indicators, key holes and fine wires in the key hole. In order to improve the accuracy of the measurement, the equal edge is constructed, usually also at the ends, with indicators for Aiming on exact scales. Tool Name JE derived from the Arab word for the "ruler" and is assumed that it was already used in the region in the time of bronze human civilization.

Alidade works on the most basic principles of geometry. Two points define a line; Therefore, when it is directed to a distant object, the straight edge of the resulting ruler also represents the actual position of this object. Two lines intersect to create a measurable and reproducible angle. One of the earliest applications of these principles was to mount Alidad to the straight edge of the diagram, which measures angles from zero to 180 degrees. To date, it is a basic device for exploration used by cartographers and building engineers for accurately measured class and soil outlines.

Mounted on a portable measuring plane, Alidade can become a tool of navigation. The magnetic field is a modern example, although its design is contrainuitive. Mechanism of observation of most recreational models tompas is its platform, usually a etched raw visual indicator; The measuring plane is a free rotating ring that is calibrated to match the magnetic north. The more old navigation tool is the naval sextant, although its design is also contrainuitive. In fact, the stationary North Star, visually aligned over the alidada, is an observer, while the ship at sea is measured by a distant moving object.

One of the oldest, most lasting, most influential and sophisticated alidad instruments was astrolabe. It was designed with several layers of concentric circles of independent measurements. Not only could be used for tasks such as triangulation, soil survey and calculation of latitude, was used to map the movement of heavenly bodies with remarkable accuracy. It is now described as a precursor of time and an analog computer.

While digital computers and accurate motors have been integrated, the same basic functioning of Alidade remains in modern use. Aircraft canT located along any axis, allowing objects in three -dimensional space. Using and measurements are determined by lasers. Telescopic alidades create the corresponding size of accurate measurements. Electronic systems targeting military warships use tools that have not changed from ancient civilizations of the Bronze Age.