I wasted A LOT of time using the image with the blue background and white lines. I did all kinds of measurements in CAD and tried to apply it to all kinds of theories. After a while, I tried to superimpose the image onto a 3d modelled sphere with longitude lines, and it didn't fit. So I tried to model an ellipse with longitude lines and when I saw how difficult that was going to be, I decided to look at the source, the spectograph (spelling?).
OMG! They're not the same at all!
Here are some DETAILS I've observed with some CAD sketching, from the spectograph (sp?), that may be worth knowing:
Things I noticed:
1) The ellipse is not centered with the grid!
2) When I moved and sized the ellipse to get it to fit, I zoomed in and realized that the upper right arc is not aligned with the grid either. By coincidence, or not, the upper right arc lines up with the major axes of the ellipse that I "fit".
3) The angle in the bottom right corner IS 45 degrees. It doesn't look like it is because the ellipse is creating an optical illusion.
The other dimensions are not important.. just stuff I was playing with. However, this image I used is very fuzzy. Having one that is clearer but not artificially distorted could help answer one question I have: The two arcs in the lower left corner, do they coincide with the center of the ellipse, which is not the center of the grid?
Food for thought.