On Sunday, January 7, 2018 at 7:03:42 PM UTC, palsing wrote:
On Sunday, January 7, 2018 at 8:18:40 AM UTC-8, Gerald Kelleher wrote:

The actual loop of Venus around the Sun is accompanied by phases changes and size increases...

Yes, but this is WRT the Sun, and there is nothing wrong with that... but this is NOT the retrograde motion that you think it is. Remember that 'retrograde' refers to the planets' apparent motion WRT the background stars, not the Sun.

You are just being silly, we see Venus move around the Sun in a closed loop so when Venus moves from right to left and behind the Sun it is moving against the background stars but as it swings in front of the Sun from its widest point it changes direction to the background stars -

https://www.youtube.com/watch?v=MdFrE7hWj0A

Now stop with the RA/Dec trash as this is all tied up to a 100% certainty. The faster planets Venus and Mercury run a loop around the Sun so the Earth's orbital input is found in the transition of the background stars from an evening to morning appearance thereby setting the Sun up as a central and stationary reference.

There are really no astronomers ,after all, if people can't distinguish the illusory looping motions of the slower moving planets from the actual loops of the faster moving Venus and Mercury then they don't deserve the title whether they consider themselves amateur and otherwise.

Anyone else want to reveal how dull they are by challenging how direct/retrograde observations are partitioned by perspective depending on whether the planet is further our or nearer the Sun ?.