On Friday, October 24, 2014 11:37:26 PM UTC+1, Mike Collins wrote:


http://mars.nasa.gov/allaboutmars/nightsky/retrograde/


NASA assume that people are able to interpret images. The animations shows
Mars in the night sky from Gale Crater but to simplify the image they
didn't include the Sun or other visible planets assuming that interested
viewers would have the sense to realise this.

The Earth from the surface of Mars and its motion around the Sun would contain roughly the same features as Venus seen from Earth with its increase in size and its phases as it emerges out from behind the central Sun,swings out to its widest point and then back in front of the Sun

http://www.halien.com/TAS/Gallery/planet/Venus02.jpg

http://artsandstars.ens-lyon.fr/venu...es.png?lang=en

The trick is to account for the motion of the outer planet looking in towards the planet in an inner orbital circuit and that involves switching references to the motion of the background stars behind the Sun thereby setting up the central Sun as a reference point for the motion of the inner planet.

Try giving the NASA animation of the Earth seen from Mars the familiar increase in size as the Earth approaches the orbit of Mars or its phases and let me know how you get on.