Because he didn't invent the Telescope so he saw it from his naked eye
The only part of Copernicus's theory that Kepler retained was the idea that the Sun is at the centre of the Solar System.
because before Copernicus there was not much technology and later on in time there was more discoveries of existence of technology. which means people were able to prove his ideas. <3 <<>> Copernicus had a theory of the way the planets move around that had some advantages over the older Ptolemaic system which had the Earth at the centre. Copernicus had the Sun at the centre, which caused problems with the church when Galileo took the theory up and promoted it as the truth. Tycho Brahe also produced a system with the Earth at the centre. Tycho's system removed some of the faults in the Ptolemaic theory, specifically the full range of Venus's phases. Finally, the theory that lasted until modern times was that of Johannes Kepler (1609). He used the new idea of elliptical orbits, and also followed Copernicus in placing the Sun at the centre. Kepler's theory was generally accepted after Newton's expanation of elliptical orbits in terms of the theory of gravity.
Johannes Kepler
Copernicus proved to mankind that the sun was the center of the universe, not the Earth. We know now that he was mostly correct. The sun is the center of the solar system.
Galelei derived his theory from Copernicus. To Copernicus it was just a theory. Galilei managed to prove it when he invented the telescope and was able to see the moons orbiting Jupiter.
The astronomical telescope.
Because he didn't invent the Telescope so he saw it from his naked eye
Copernicus is the first in modern times, but he may have been basing his theory on the work of an earlier Greek Natural Philosopher. Galileo used a telescope and mathematics to prove Copernicus' hypothesis.
Galileo's invention of the telescope helped him observe the phases of Venus, the moons of Jupiter, and sunspots, which provided evidence for the heliocentric model proposed by Copernicus. These observations challenged the geocentric view of the universe and supported the idea that the Earth revolves around the Sun.
Copernicus created the mathematical theory to prove that the Sun, not the Earth, was the centre of our solar system. Galilei provided the calculations and observations to prove Copernicus' theory.
The only part of Copernicus's theory that Kepler retained was the idea that the Sun is at the centre of the Solar System.
Galileo was the first scientist to use a telescope to make discoveries about the Sun, Moon and planets. His discoveries raised serious doubts about the ancient Ptolemaic theory in which the Earth is at the centre of the Universe. Copernicus's theory of 1543 places the Sun at the centre instead. It explains some of the things that the Ptolemaic theory fails to explain, like the full range of Venus's phases that Galielo discovered. Galileo reasoned that this must prove that Copernicus's theory is right. However Galileo was wrong about this because Tycho Brahe's model explains the phases of Venus correctly yet still has the Earth at the centre. In the end, all these theories were rejected when Johannes Kepler produced his new theory in which the planets travel in elliptical orbits. It was generally accepted later, after Newton's discoveries showed theoretically that the planets must move in elliptical orbits under the force of gravity. However, Kepler's theory did have the Sun at the centre, so in one respect Copernicus was right.
Galileo did not prove that Earth was not flat (It had already been agreed that it was round). Galileo invented the telescope and used it to prove that there were objects which did not orbit the Earth, supporting Copernicus' Heliocentric model for the universe. The Earth was known to be round by the ancient Greeks, but I do not who it found out initially (sorry).
This is an example of how evidence-based observations can lead to the acceptance of a scientific theory. Galileo's use of a telescope provided tangible proof of the theory of planetary motion, which helped in gaining acceptance within the scientific community. It illustrates the importance of empirical evidence in scientific advancements and theory validation.
I think you are referring to Nicolaus Copernicus.
Nicolus Copernicus proved that sun is the center of the solar system in 1530. In that year he completed and gave the world his great work De Revolutionibus.Through this work he asserted hat the earth rotated on its axis once daily and traveled around the sun once yearly.