USA HISTORY

Detailed explanation-1: -Known as a prismatic astrolabe, it too is used for making precise determinations of the positions of stars and planets. It may sometimes be used inversely to determine the latitude and longitude of the observer, assuming the star positions are accurately known.

Detailed explanation-2: -How was a mariner’s astrolabe used? The instrument was used to help determine the ship’s latitude from the height of the Pole Star or of the sun. At night, the Pole Star was sighted directly through small pinholes in the two vanes mounted on the pivoting alidade or rule.

Detailed explanation-3: -astrolabe, any of a type of early scientific instrument used for reckoning time and for observational purposes. One widely employed variety, the planispheric astrolabe, enabled astronomers to calculate the position of the Sun and prominent stars with respect to both the horizon and the meridian.

Detailed explanation-4: -Ancient world An early astrolabe was invented in the Hellenistic civilization by Apollonius of Perga between 220 and 150 BC, often attributed to Hipparchus.

Detailed explanation-5: -sextant, instrument for determining the angle between the horizon and a celestial body such as the Sun, the Moon, or a star, used in celestial navigation to determine latitude and longitude. The device consists of an arc of a circle, marked off in degrees, and a movable radial arm pivoted at the centre of the circle.