Flat Earth Debunk: Light from the sun is not parallel

This is something new I've heard from a few debates on Youtube. Globe earth side breaks out the usual geometry (height of the sun from parallax measurements, Eratosthenes measuring earth curve based on the assumption solar rays are parallel, where would the sun need to be in order to see a sunset, latitude measurements to Polaris or the Southern Cross, etc)

Then the Flat earth side claims that the geometry is invalid because light doesn't travel in straight lines.

Globe earth doesn't deny light can bend, globe claims light can bend in measurable and quantifiable amounts, and we have lab tests to back up just how much it bends and what causes it. Refraction, diffraction, and the seemingly dual nature of particle and wave properties of light are not new concepts, they've been well studied. Even grade school students experiment with this and get to see for themselves how light behaves.

Refractive indexes, air layers, these are all very well studied and known about, even since 1,000 years ago when the Arabic scholar Ibn al-Haytham wrote his book on optics, and included discussion of how the atmosphere refracts light and how to measure it.

We can even see this in crepuscular rays, when they are viewed from above in an aircraft or a drone, it's obvious the rays are parallel and not diverging, meaning the light causing them is coming at us is effectively parallel.