^^^
https://www.youtube.com/watch?v=NruZ5vzRhQ4 <-- includes the requested video of the Sun shrinking as it sets. Cool dense air allows for this shrinking/growing effect to be photographed best.
How the Sun Works on the Flat Earth - Death of NASARofl, comments already debunked it:
#1 - The sun is not changing size in any of the sunsets or sunrises in these videos, its GLARE is diminishing. The reason is because the sensing element is saturated (be it a digital sensor, film emulsion, and, to some degree your eyes). As it sets (or rises) its light has to travel through much more atmosphere. This is why it is easier to look at at sunrise and sunset. Also, if you look at the sun when it is high in the sky you can see its edge through the glare (hence the 'to some degree' I mentioned), but you will only see the larger glare with a video or camera (unless you lower the exposure significantly with filters).
IF YOU REALLY WANT TO TEST THIS OBJECTIVELY, you would need to use filters so that the edge of the sun is visible throughout the video.
#2 - Perspective never DIVERGES! THAT IS A RIDICULOUS THEORY! It is well established that the further away a given object is from you, the smaller its apparent size becomes, PERIOD! And in similar fashion, the further that two parallel lines (like say train tracks) are away from you the smaller the distance between them appears! That is what perspective is. THE DISTANCE BETWEEN TWO PARALLEL LINES WILL NEVER START TO GET BIGGER AGAIN AS DISTANCE INCREASES.
#3 - If the Sun really were going around in a circle of a diameter say 8000 miles (as I suppose many flat earthers believe; otherwise, the measure of distances wouldn't add up) YOU WOULD NEVER SEE IT SET! If you are standing at the equator at high noon (say La Mitad del Mundo in Ecuador) the sun will set almost exactly 6 hours later (no matter what time of year). According to the idea of the Sun travelling in a circle 8000 miles in diameter it would then be directly over a point on Earth that is 5657 miles away (by direct line of sight). Also, many of FEs believe the sun is only 3300 -3800 miles high. If the sun's light were just shining in a local area and if at sunset we are just seeing it diminish, at 3300 miles high it would disappear at more than 30º above the horizon! PERSPECTIVE WOULD NOT CHANGE THAT. I use 3300 as opposed to 3800 because the lower altitude would bring it closer to the horizon at sunset (although not very much). Even if it were only 1000 miles in altitude it would still 'diminish' at more than 10º above the horizon.
#4 - According to many FEs, the sun has a diameter of 34 miles and an altitude of 3800 miles. If that were so, at a point 3800 miles high and 5657 miles away its distance would be over 6814 miles (by direct line) and it would appear little more than half the size (at sunset) than it looks overhead. Anyone can go look at the sun at high noon and look again at sunset and see that this isn't even close.
The sun is going in circles over the flat Earth. How is it not falling down and what's the force making it move in circle?