Answer:
They had different beliefs and backgrounds.
Step-by-step explanation:
Ptolemy believed in geocentric model of the solar system -the earth at the center and the sun, other planets and stars revolved about it. His belief was based on his observation that sun and other objects in sky seemed to revolve about the Earth as they rose and set in one day.
Copernicus while reading a book, constructed the theory of heliocentric system which was later proved through observations.