Modelle des Kosmos: Modelle der Erde
Measuring the Earth
Since ancient times, the Earth is mapped using lines of latitude and longitude, which facilitates the exploration of its surface and size. Well into the 18th century, longitude is calculated exactly with the aid of eclipses of the moon, which are observed from two locations that lie apart in an east-west direction. From the time difference between the beginning of the eclipse at the two observation points, the distance of the longitude is calculated. From the 15th century, the precalculated daily positions of celestial bodies are written down in so-called “ephemerides,” which accompany sailors all over the world.