On Tuesday, July 19, 2016 at 1:23:53 PM UTC-7, Gerald Kelleher wrote:
http://apod.nasa.gov/apod/ap160717.html

The racetrack analogy applies to Mercury as it does to Venus although Venus gives observers a clearer view as it runs its circuit along with its phases -

http://www.popastro.com/images/plane...ary%202012.jpg

An evening appearance of Mercury represents its orbital course when it emerges out from behind the Sun to its widest point seen from a slower moving Earth before turning back in while a morning appearance is when it passes in front of the Sun and moves to its widest point in the opposite direction..

The people at NASA/APOD need to grow into adults as Mercury doesn't "trail or lead the Sun", the Sun is stationary and the planet moves .

Gerald, you need to keep in mind that this photo shows the position of Mercury over several successive evenings with respect to the Sun. As explained in the text, each photo was taken when the Sun was 10 degrees below the horizon. This photo shows how Mercury swings around the Sun. Isn't it pretty?

This photo does emphatically NOT show the motion of Mercury with respect to the fixed stars, and that motion would be vastly different. Of course, we can't actually see the stars while the Sun is only 10 degrees below the horizon, but we certainly know exactly where they are.

With respect to the stars the retrograde of Mercury would look something like this...

https://michellegregg.files.wordpres...ment.jpg?w=593

Very different, eh?

After all, it is all a matter of perspective, which is always the case.