<P> The precessional eras of each constellation, often known as Great Months, are approximately: </P> <Table> <Tr> <Th> Constellation </Th> <Th> Year entering </Th> <Th> Year exiting </Th> </Tr> <Tr> <Td> Taurus </Td> <Td> 4500 BC </Td> <Td> 2000 BC </Td> </Tr> <Tr> <Td> Aries </Td> <Td> 2000 BC </Td> <Td> 100 BC </Td> </Tr> <Tr> <Td> Pisces </Td> <Td> 100 BC </Td> <Td> AD 2700 </Td> </Tr> </Table> <Tr> <Th> Constellation </Th> <Th> Year entering </Th> <Th> Year exiting </Th> </Tr> <Tr> <Td> Taurus </Td> <Td> 4500 BC </Td> <Td> 2000 BC </Td> </Tr>

Polar axis of earth is shorter than equatorial axis