Feature by Manjeet aunty
Today, we all use navigation on our smartphones and other devices to not only find directions on the map to our specific destination, but also the time to reach and traffic scenario.
The navigation system has evolved through the centuries – from using the Sun (the most predictable object in the sky) to determine the time and direction in ancient times, to using satellites in the modern era.
In olden days, sea explorers and merchants faced various challenges to navigate and developed different types of instruments to overcome the same.
Some of those important instruments are discussed below.
Compass
The first ever compass is believed to be invented in China in the third century and later used for navigational purposes during the eleventh century CE. These compasses were made from lodestone, a natural form of iron ore having magnetic properties.
Astrolabe
This instrument was used to find the positioning of various astronomical objects to navigate in the ocean. Also, it was used to measure the angle of a slope or elevation of an object. It was a kind of clinometer in
olden days.
Quadrant
It was designed by the Greek astronomer, Claudius Ptolemy, in 150 CE. It was used to measure the height of astronomical objects above the horizon along with the distance between them. The quadrant was in the shape of a quarter-circle and was able to measure angles up to ninety degrees.
Cross-staff
It was believed to be invented in around 400 BCE, however, it was used for navigation only in 1514 by the German mathematician Johannes Werner.
It was used to measure the altitude of the Sun by allowing it to cast the shadow of a vane (cut pieces) onto another vane (the horizon vane) mounted at the front of the instrument. It has been variously used for astronomical observations, for surveying, and for navigation
Theodolite
It was designed by English mathematician and surveyor Leonard Digges in 1571 to measure angles in both the horizontal and vertical planes. The theodolite has been considered to be the most modern and
accurate instrument that most surveyors were familiar with in 1787.
It is in use even today in some parts.