Clamp the index bar at 0 degree 0.0′. Hold the sextant vertically and look at the heavenly body. Turn the micrometer one way and then the other, while looking at the body. The reflected image of the body will move above and below the direct image and should pass exactly over it.
How to Use a Sextant?
A sextant is a navigational instrument used to measure the angular distance between two visible objects. It is primarily used in marine navigation, but is also useful in land surveying, astronomy, and atmospheric science. The sextant is an important tool for measuring angles and distances on the open sea, and is still used today by professional sailors and navigators. To use a sextant, one must first understand the basics of navigation.
The sextant is an instrument with two mirrors, a graduated arc, and an index arm. The mirrors are set at a 60-degree angle to each other. The graduated arc is used to measure angles and is graduated in degrees from 0 to 120. The index arm acts as a pointer and is used to measure angles.
To use a sextant, start by placing the index arm on the zero mark of the graduated arc. Sight along the index arm to a distant object. Then, adjust the mirrors so that the reflection of the object is seen in both mirrors. Read the angle off the graduated arc.
To measure the angular distance between two objects, adjust the mirrors so that the first object is seen in the first mirror and the second object is seen in the mirror of the second mirror