What is a compuse?

An astrolabe tells directions by using the sun moon and stars to locate position?

The primary tools are the compass, a sextant and a chronometer. The compass allows the ship to steer in a specific direction. The sextant is used to measure the angle between the Sun and the horizon. By measuring that at noon, the point the Sun is directly overhead, it allows one to determine the latitude. With a Chronometer and the appropriate tables, the sextant can be used to calculate the latitude and the longitude using the angles of the various stars.