I have read the various answers to this question provided by people with a higher intellect than me, however I am still confused. Even from the ISS your view is to the horizon some 1,435 miles in all directions. Is the view not the same as being on a very small island in the middle of the sea on earth but just covering a larger area?

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    $\begingroup$ This question is asked every other day somewhere. The answer is 0m, watching an island or a ship emerge or disappear. Do a little calculation, visit a harbour town, use nautical rules of thumb, whatever. I can see a curvature from horizon to horizon clearly from 550m above the sea (Atlantic island dweller) using the handrail of the terrace for comparison, or a mason level held with the straight arm. You can easily calculate distance to the horizon, then a little trig and you have the angle. en.wikipedia.org/wiki/Horizon#Distance_to_the_horizon $\endgroup$
    – user20217
    Jun 10, 2020 at 14:45
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    $\begingroup$ Basically anywhere at ground level, as long as your horizon is far enough away. you won't see it at 0m because the surface roughness of the earth would almost certainly get in the way, but head height is fine. There's a good example here: flatearth.ws/pontchartrain $\endgroup$
    – Will
    Jun 11, 2020 at 7:41
  • $\begingroup$ @gansub: imgur.com/9M66cs5 With the eye it's even more obvious because of ~double the fov compared to the wide angle lens. I did not construct the handrail deliberately ;-) Height ~550m above sea level, 2/3 sensor, f/16, 18mm focus distance. I won't take the fun of calculating fov and drop angle. It's a small world ;-) $\endgroup$
    – user20217
    Jun 13, 2020 at 9:17


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