I heard the big sunset moon is an illusion before (referring to the video). [redacted]. I've measured it myself often. When the full moon is high overhead, with my hand extended all the way out, I can easily cover it with my thumb. But when it's extra large on the horizon, with my hand fully extended, sometimes it takes 4 fingers to cover it.
It's caused by refraction of the light as it hits our atmosphere, which is more pronounced the lower it is on the horizon. It's also why the moon & the sun are sometimes slightly oval when on the horizon. The refraction may be greater in some areas depending on the humidity, barometer, & pollution.
Many astronomers may not see much refraction because they work in areas with good visibility conditions, like low humidity, clean air, or low barometers, as near mountains or desserts.
Here in my polluted lowland city right next to the Great Lakes where it's often very humid, with a barometer above 30", on a rare extra large moon-set, 4 fingers won't cover it all, but depending on the weather, sometimes 2 fingers will cover it.
In a telescope, I can see Jupiter & Saturn shimmer, expand & contract as I'm watching it because of atmospheric refraction & distortions. We already know light refracts when passing from a vacuum, to dense atmosphere. The curvature of the earth & its atmosphere acts more like a lens when the moon is close to the horizon.
In fact, at the time of moon-set, sometimes the moon is already below the horizon, & what you are seeing is it's refracted image being bent by the atmosphere like a lens & prism. No illusion.
Mind your language.
Refuting a comment with vulgarity isn't productive or civil.
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