A prominent feature of the achievement of Muslim scholars in mathematical geography and cartography was the invention of scientific instruments of measurement. Among these were the astrolab (astrolabe), the ruba (quadrant), the gnomon, the celestial sphere, the sundial, and the compass.

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.

Muslim scholars invented and refined a number of scientific instruments in mathematical geography and cartography. These included the astrolabe, quadrant, gnomon, celestial sphere, sundial, and compass.

John Campbell

A sextant is a doubly reflecting navigation instrument that measures the angular distance between two visible objects. The primary use of a sextant is to measure the angle between an astronomical object and the horizon for the purposes of celestial navigation.

The Columbus navigated his ship across the ocean using celestial navigation. In his log he commented that he performed celestial sightings with a quadrant. Celestial navigation requires the sailor to use an instrument, like a sextant, to find the angle between a star/planet and the horizon.

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.

Holding the sextant in your right hand, raise the instrument to your eye. 3. Look at any horizontal straight edge (the sea horizon or the roof of a building, for example) and move the index arm back and forth using the quick release levers.

Instructions

1. Tape a drinking straw to the bottom edge of a protractor.
2. Tie one end of a string to the center of the protractor. One the other end of the string, tie a steel washer or other mass.
3. Locate the North Star through the straw.
4. Look up the latitude on a map or online and see where you may be.

All it is is a device that measures the angle between two objects. The sextant makes use of two mirrors. With this sextant, one of the mirrors ( mirror A in the diagram) is half-silvered, which allows some light to pass through. In navigating, you look at the horizon through this mirror.

To do this, Columbus used celestial navigation, which is basically using the moon, sun, and stars to determine your position. Other tools that were used by Columbus for navigational purposes were the compass, hourglass, astrolabe, and quadrant.

Herein, we have enlisted 30 types of navigational equipment, both old and new, which are present on all merchant ships.

• Gyro Compass. It is used for finding the right direction.
• Radar.
• Magnetic Compass.
• Auto Pilot.
• ARPA.
• Automatic Tracking Aid.
• Speed & Distance Log Device.
• Echo Sounder.

Magnetic compass, in navigation or surveying, an instrument for determining direction on the surface of Earth by means of a magnetic pointer that aligns itself with Earth’s magnetic field.