You have gotten it wrong Allen.. even if it was due to my own confused state at the time, which I cleared up later. Take this single part of yours below as an example of our combined error which Neville also corrected. PM asked : Does the view of the rotation of that star vary proportionally with the radius of rotation of the observer.. Allen 1. that is exactly what the astronomer told you.... astronomer: Quite simple. The earth is tilted at that part of the sky. The tilt is maintained toward that part of the sky throughout the orbit around the sun, and so the star always appears in the same spot." ..that astronomer probably misunderstood my question or I did. We were confusing angle to the horizon with angle of observation . old subject. look carefully at the above.. as selected here this question, Does the view of the rotation of that star vary proportionally with the radius of rotation of the observer.. got this answer, Quite simple. The earth is tilted at that part of the sky. The tilt is maintained toward that part of the sky throughout the orbit around the sun, and so the star always appears in the same spot." Which is as Neville said, a big NO NO. The answer is, "no." The stars are so far away in the heliocentric idea that the difference in radius between R and 1AU is negligible (manifesting itself only in tiny parallax and slightly elliptical trails as opposed to circular trails). The rest of your post is irrelevant. The point has been resolved. Philip