Ketu-Chakra is total 10800 years orbital cycle of various Comets described in Sanskrit Ancient Astronomical Books . These books describe total 1001 comets out of which 26 are described in detail with Orbital periods & their forms . It includes many discovered Comets by modern astronomy & many are still mystery to modern science . This book also describes 3 more outer orbit planets with Uranus, Neptune & Pluto . Ancient Aryans discovered these planets before 1450 BC with their properties & orbital periods .Readers will get new fascinating descriptions of celestial events like star formation, lost planet and moons of Jupiter & Saturn . This 3600 year old Sanskrit work describes 65 moons of Jupiter & 84 moons of Saturn with names .This is real Ancient Science Book which historians of sciences, astronomers & astrologers should not miss .