(Can sail into! How to calculate the position of the ship by observing the relationship between the moon and the constellation?

Using sextant, we can observe the height of stars; With a compass, you can observe the direction of the stars.

The position of the star relative to the earth is fixed at a certain moment, and the position of the star at the observation moment can be calculated by using the astronomical calendar.

When the position of the star is determined and the azimuth and elevation relative to the star are determined, then the geographical position of the observer can be calculated.

What I have said above are all popular principles, for your convenience.

In practical calculation, it is very complicated to abstract space into a sphere, and the error is great. It is usually necessary to observe two or three objects at the same time to reduce the error, which is difficult to calculate.

For some special cases, such as Polaris (azimuth is about 0), the position of the transit of the sun (when the sun passes through your longitude, it is called the transit, and the azimuth is 0 or180), the calculation is relatively simple.

At present, the crew examination is no longer required to take the astronomical examination, and the new ship does not need to be equipped with a sextant. Few people can sail with astronomy.