A navigator's aid is a tool used by navigators to help them find their way. The most common aids are maps, stars, sextants, lorans, compasses, quadrants, and nautical almanacs. Maps provide a visual representation of the area being navigated, while stars can be used to determine direction and time. Sextants measure the angle between two objects, such as the sun and the horizon, to calculate latitude and longitude. Lorans are radio navigation systems that use signals from multiple transmitters to determine position. Compasses are used to determine direction, while quadrants measure the altitude of celestial bodies. Finally, nautical almanacs provide navigators with information about the positions of the sun, moon, and stars.