The problem goes far deeper than just magnification of the sun when it is far away. As we all know, the FE sun is claimed to move around the geographic north pole in an essentially flat path, never actually going below the horizon. We are told that perspective and / or atmospheric effects cause it to APPEAR to go below the horizon at a distance, and also APPEAR to remain the same size in the sky. We are given this information in a manner suggesting that it is enough to explain the apparent movement of the sun, while they seem to utterly ignore the fact that the apparent elevation angle and size of the sun are not the only problems with this model: there is also an apparent left-to-right shift happening.
I calculated the actual position of the nearby sun above the flat earth from the viewpoint of an observer located at 45° North latitude on the day of the September Solstice. I did this using simple trigonometry, as illustrated below, calculating the distance and direction to the sub-solar point on the earth's surface and then the elevation angle up to the sun knowing the distance and height. I did this ignoring any atmospheric or perspective effects, which matches how Rowbotham and other FE calculate the sun's height. (Notice in the wiki, for example, that during the section on
calculating the height of the sun, no allowance is made for the sun
appearing to be at 45° elevation angle while
actually being somewhere else. No, it is assumed to
actually be where it
appears to be, at 45° elevation) I did ten minute increments all night and day, midnight to midnight.
I then pulled information from the
US Naval Observatory web site listing the projected direction and elevation angles for the same geographic location and also in ten minute increments. I then calculated the difference between observation and calculation, and graphed the result. This number is the magnitude of the FE proposed perspective and atmospheric effects. The X axis is the difference between the direction the sun is observed, and the direction it is supposed to be at that time of day. The Y axis the difference in how high above the horizon the sun should be, absent the proposed perspective and atmospheric effects. This curve and the one that follows are both slightly asymmetrical due to my local apparent solar noon not lining up exactly with clock noon, so the USNO numbers are coming in slightly ahead of my calculated numbers.
One more simple equation allows us to combine the left/right offset effect with up/down offset effect to calculate a total offset. When the sun rises/sets the absolute effect is at its maximum, and the result is a vector effectively moving the sun's apparent position a total of 45° from its calculated position. That is 1/4 of the way across the sky! I suspect the typical FE who has not done the math would expect the atmospheric effects to be at a minimum at noon and maximum at sunrise/sunset, and he or she would be correct. I also suspect the typical FE would imagine these effects changing in a pattern that makes intuitive sense, maybe a straight line or a sine wave; in this he or she would be incorrect. Observe the total effect curve:
The point of all this: those of you proposing optical effects to explain the difference between observed sun and moon locations and where those bodies should be above your flat earth? THIS is what your optical effect must achieve.