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 Sextant?
The sextant is a navigational tool used to measure the angle between two objects, usually the horizon and the sun or a star. It is a valuable tool for sailors and navigators to accurately calculate their latitude and longitude. With a bit of practice, anyone can learn how to use a sextant.
Before you begin to use a sextant, you will need to ensure that your instrument is properly calibrated and that you have a clear view of the horizon. If you are taking a reading from the sun, it is important to wait until it is in the correct position, and the sunlight is not too bright.
To use a sextant, look through the horizon mirror and find a suitable object to measure against, such as a star. Once you have found your object, adjust the index arm of the sextant until it is in line with the object. The sextant should then be turned until the horizon is visible in the horizon mirror.
When you have the horizon in the horizon mirror, you will need to adjust the index arm until it is in line with the star or sun. Once the index arm is lined up, you will need to adjust the sextant to the correct angle. You