Medieval Astronomical on the Old Town Hall of Prague, 1410. The third oldest of these clocks and the only one still working. The movable circle inside the outer black hour ring is marked with the signs of the zodiac which indicates the location of the Sun on the ecliptic; the starburst shows the position of the vernal equinox. The moon's movement, sidereal time and changing time of sunset are also depicted (closeup, 2nd of 3 pins).
