Answer
Nicolaus Copernicus was an astronomer who discovered a heliocentric system, that the planets orbit around the Sun; that Earth is a planet which, besides orbiting the Sun annually, also turns once daily on its own axis; and that very slow changes in the direction of this axis account for the precession of the equinoxes
in other words he discovered that the sun was stationary in the center of the universe and the earth revolved around it.
The heliocentric model was generally rejected by the ancient philosophers for three main reasons: If the Earth is rotating about its axis, and orbiting around the Sun, then the Earth must be in motion. However, we cannot ``feel'' this motion. Nor does this motion give rise to any obvious observational consequences
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Brahe showed irregularities in the Moon's orbit and discovered a new star in the Cassiopeia formation. Brahe invented many instruments such as the Tyconian Quadrant which were widely copied and led to the invention of improved observational equipment
The New Star. Tycho made his first significant discovery on November 11, 1572. Observing the night sky from an uncle's home, Tycho was amazed to see a new light brighter than Venus in the sky
-----could not figure out who some challenges they faced
He did not accept the heliocentric theory
He vehemently rejected the Copernican model because he had no sense that the earth moved and, more importantly, he could not detect parallax in his observations. He proposed a variant in which the earth is fixed, the moon and sun orbit it, and all the other planets orbit the sun.
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