honcheonsigye is a celestial globe clock created by song i-yeong in 1669. the clock has an armillary sphere with a diameter of 40 cm. unlike chinese astronomical clock, it could measure the accurate time by observing the whole movement of universe. it is the only remaining astronomical clock from the joseon dynasty. an image of the clock's sphere is shown on the reverse of the 2007 issued 10,000 won banknotes.