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. It is almost impossible to actually watch the inferior planets move backwards WRT the stars because it all happens very close to the Sun, wjich pretty much wipes out all but the brightest stars in that area, but that does not mean they we cannot calculate these planets' positions. See these...

http://www.nakedeyeplanets.com/mercu...r-oct-2023.png

http://www.nakedeyeplanets.com/mercu...b-may-2012.png

.... for a depiction of Mercury's path among the stars, understanding that Venus moves against the stars in a similar manner. Check out the animation near the top of the [age, here...

http://www.nakedeyeplanets.com/movements.htm

.... to see the loops and zig-zags of all the planets' movements over 5 years, from 2000 through 2005.