I found this bit over in your "sources" place:

http://theflatearthsociety.org/forum/index.php?topic=58658.0#.U0H9zlck1p0 The problem with this author, is they are failing to realize that the difference in angle is going to be so minute, because when compared to the distance between the earth and the sun (whether in the geo-centric model of 3000 km as believed by the FE of this particular forum, or in the helio-centric model, being 1 Astronomical Unit, or ~ 1/63,281 of a light year), compared to the nearest star, at 4.21 light years away. So mathematically speaking, the author is correct, practically speaking though, it doesn't prove it either way in this case, because the difference would be, excuse the pun, astronomically small.