oriel36 wrote:

Copernicus and Kepler did not have telescopes to admire these
brilliant heliocentric events and they relied on the faster Earth
overtaking the slower moving outer planets to infer the Earth's
orbital motion between Venus and Mars around the central star -

Hi, there, and just to clarify a point as to observational
techniques that could be of interest to s.a.a.: Kepler indeed
based his theories of planetary motion on the naked eye
observations of Tycho Brahe. If I'm correct, he published
his first formulations around 1609, the same year that the
telescope was coming into astronomical use. Later on, of
course, Kepler _did_ use telescopes, and if I'm correct
designed a Keplerian type of refractor.

Thus, if I understand correctly, it is quite right to say
that Kepler formulated his theories before the telescope
came into astronomical use and he became one of its users
and designers.

Most appreciatively,

Margo Schulter

Lat. 38.566 Long. -121.430