Click here to see an example of a secure and flexible seat in trot. Watch closely as the rider's hips, pelvis, and legs flex freely with the horse's movement. Horse's willingly raise their back up under a seat like this, probably because it feels a bit like getting a gentle back rub with each step.
The celestial sphere is divided by the celestial equator. In astronomy and navigation, the celestial sphere is an imaginary sphere (ball) of a very large unspecified size. The sphere is concentric with the Earth. This means that the celestial sphere and the earth have the same centre. They also rotate upon the same axis.
As such, it differs from a celestial globe, which is a smooth sphere whose principal purpose is to map the constellations. With the Earth as center, an armillary sphere is known as Ptolemaic.he sphere, built in 1433 was named Honcheonui (í¼ì²ì). The Honcheonsigye, an armillary sphere activated by a working clock mechanism was built by the Korean astronomer Song Iyeong in 1669. It is highly valued in term of clock-making technology and is the only remaining astronomical clock from the Joseon Dynasty.