On Saturday, February 16, 2019 at 9:28:10 AM UTC, corvastro wrote:
On Friday, January 25, 2019 at 12:58:32 PM UTC-8, Gerald Kelleher wrote:
Much easier to let the timelapse explain things as it becomes a tangled descriptive issue otherwise -

https://www.youtube.com/watch?v=L74B98ITKEA&t=156s


The stars move constantly from left to right due to the Earth's orbital motion and a stationary Sun.

No fixed background of stars by which to gauge the faster motions of the inner planets.

When the motions of the faster planets are referenced to the stationary Sun, their motions against the background stars become secondary even when they display direct/retrograde motions.

The retrograde motion of the faster moving planets is determined by their motion in front of the Sun and between the Earth. Their direct motion against the background stars is when they pass behind the Sun.

The direct/retrogrades are not an illusion but a signature of a closed orbital loop -

https://www.popastro.com/images/plan...ary%202012.jpg


So, the historical trajectory is that direct/retrogrades of the slower planets were discovered 500 years ago and broke the geocentric hold on astronomy whereas today satellite imaging and common sense adds to the story which should delight those who can be inspired.

Direct/Retrograde motions were long before 500 years ago, possibly 3000 years or more. That is the reason the planets were called "wandering stars".

Newbies like you are so endearing as they are hardly aware the technical details which others in the newsgroup should have adopted over a decade ago.

The first Sun-centred astronomers worked off the Ptolemaic framework where the Sun moves directly through the constellations whereas the planets wander north and South of that line -

http://community.dur.ac.uk/john.luce...n_ecliptic.gif

"Moreover, we see the other five planets also retrograde at times, and
stationary at either end [of the regression]. And whereas the sun
always advances along its own direct path, they wander in various
ways, straying sometimes to the south and sometimes to the north; that
is why they are called "planets" [wanderers]. Copernicus


The RA/Dec gob****es have the Sun also wander against the constellations which is why they have turned into nuisances rather than have any serious interest in astronomy -

http://community.dur.ac.uk/john.luce...solar_year.gif

The reason there is little traffic through this newsgroup despite the absence of spam and whatnot is that any lower form of reasoning and interpretation doesn't survive for long or is restricted to a magnification/identification exercise.

Pity there is nobody reliable in the newsgroup to bring you up to speed.