Navigational Sextant

LEGO Ideas - Navigational Sextant

In the past, navigating a ship in the open ocean was considered to be dangerous and challenging. Countless lives and ships were lost due to poor navigation. Unlike coastal navigation where objects along the coast can be visibly used as reference points for determining ship position, only the Sun, the Moon, and the stars are observable in the vast open sea. To make open-ocean navigation practicable at that time, devices and techniques that could exploit the positions of those astronomical objects to determine ship location were needed to be invented.

The sextant was the key to solve that problem. Its principle of operation was realized in the 1700s, and it has been used for hundred years. It has odd-looking shape around one-sixth of a circle. Therefore, it is called sextant from the Latin sextus, or “one-sixth.” It is primarily used for measuring the angle between the horizon and objects in the sky such as such as the Sun, the Moon, or a star. The operation lies on the double reflection of the light ray to enable the observation of the horizon and an astronomical object at the same time. The double reflection is made possible by the index mirror on the movable index arm and the horizon mirror on the sextant frame. By Moving the index arm along the arc until both objects are aligned as seen from the telescope, the relative angle can be measured. The angle read from the index-arm dial can then be used to calculate the ship position on a map or chart, which is very vital in open-ocean navigation where no land is in sight. The techniques used in this ship-position calculation is still considered to be very complicated even for today.

The motivation for this creation started when I had a chance to touch and feel the real sextant. The first thing that has intrigued me was its shape. After learning its fundamental, I became even more obsessed with this instrument. I have tried to imitate all the features of the real sextant as accurately as possible. Here, the arc has the scale similar to the real one. The index arm is also movable and has the dial that can be used to read the measured angle. Glass filters of this sextant are also movable to adjust the brightness of the objects in observation. The sextant components are cautiously positioned to replicate the feel and intricacy of the real device. 

The display was built with two interchangeable stands, which are rotatable to display the sextant at various angles. One stand has a cradle so that the sextant can be picked up and play with. Another stand secures the sextant upright for display only. The sextant itself is carefully designed and built to be displayable and playable. This creation is intended to reflect the sophistication of the device and its importance in open-ocean navigation that has helped initiate the prosperity and connectivity among the nations that have made up the world we live today.