Lunation is a watch term used to describe a specific period of time in which the Moon passes through its phases. It is the time it takes for the Moon to complete one full cycle from new Moon to new Moon, which is usually 29.53 days. This term is often used in reference to watchmaking and the accuracy of different types of watches. In the context of watchmaking, lunation can be used to measure the accuracy of a watch by the amount of time it takes for the hands to make one full cycle around the dial.
