This topic has really shown me my boundaries of intelligence. I still don't understand how it's not proof of a globe earth, that a large ship disappears over the horizon, bottom first, and when zoomed in on still does not expose the bottom part. It seems that if the ship gets zoomed in on and the bottom reappears it would NOT prove globe earth. It seems that if the world is curved, this would make sense.

I've seen video where the bottom DOES reappear after zooming in ... after it looks like it had disappeared, and after travelling a distance where it should not be there given curvature math.  There is an optical phenomenon where the bottom will converge with the plane underneath it.  And at some point the limit of the optics, the zoom, would be reached, and the same phenomenon would occur despite the magnification.  And then I've seen another phenomenon demonstrated where the bottom actually gets obscured by a mirror-image reflection of the higher part above the waves.  You can see birds flying over being reflected in mirror image on the bottom part.  But the bottom is still there, just optically hidden beneath a mirror image reflection of the higher part.

Given that one CAN observe the phenomenon of the bottom disappearing, and then have it reappear when you zoom in ... proves that the phenomenon is not necessarily related to earth curvature.  It's pretty simple logic.

I have seen flat earthers use lasers, sounds beams, and GPS devices accurate to within centimeters to demonstrate lack of curvature.  Unless the results were completely made up, and faked, that is the kind of proof that's irrefutable.  I've seen pictures taken by third parties who were not interested in the curvature problem where entire mountains can be seen from distances that should be impossible given curvature math.  Unless there was lots of "refraction" going on, then that would not be possible.

If globe earthers were to do the same thing, measure the distance between the tops of two buildings separated by a number of miles, and then compare it to the distance between their bottoms (assuming they were plumb and level) ... and show that the tops were farther away from one another than the bottoms, then I would consider that proof of curvature.  But I have not seen them produce anything like that.  I've seen one globe earther use lasers, but the result they had could have been achieved if the laser at the origin was tilted even slightly upward.  But when you do it the other way, and the laser still hits an object that should be obscured, that's much harder to fake.  Again ... unless the entire video was staged and fabricated.  I've seen flat earthers use GPS devices to show that the tops and bottoms of two buildings were exactly the same distance apart ... to within centimeters.  In addition to lasers, and GPS, they have used directed sound beams.

I don't trust anything that comes from NASA ... because they have been caught red-handed producing fakery.  They are on record admitting that their "pictures" of globe earth are composites.  And they have produced composites with widely varying look and sizes of continents, etc.  They've been caught using green screens while pretending that some astronaut was in space.  Why?

I get that. The point that the article I linked to made is that, there are times when you zoom in and it still does not come back. Some objects, no matter how much zoom you put on them, part of the object is still obscured.
There is the vanishing point where the object goes beyond your view. Some objects, you can zoom in on and they fully come back into focus. On the other hand, even with the best magnification cameras out there, there are larger objects where their entirety cannot come back into view past the vanishing. No matter how close one zooms. a percentage of the lower part of the object is still not in view. Globe earth says that it is over the horizon and being obscured by the curvature.
My point was that I don't know how a flat Earther would explain that. It seems to me that the only explanation would be that the curvature obscures the lower part of the object. We are only talking about objects past the vanishing point; i.e. out of view for our eyes.
Is this how you understand it and I'm still not getting it. LOL

As I said, there can be lots of explanation for this phenomenon.  Please produce something like the GPS experiment that flat earthers have used, and then I'm all ears
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Now, I have not completely bought into flat earth due to the claim that refraction is possible in some cases.  So I go both ways on this.  If there's another possible explanation for the phenomenon, then I don't consider it hard proof.  While I think it unlikely that refraction can explain all the cases I've seen, I can't rule it out.  Otherwise, I would be 100% convinced of flat earth.

Please post one that you don't think checks out.

Even those ancients who MAY have believed in a flat Earth believed that the Sun went under the rim of the world.

The great irony here is that modern flatters continually appeal to the “common sense” evidence of the senses - except when it comes to the Sun rising and setting. THEN they invoke terms like optical illusion and hocus pocus mechanisms.

Just like with the gravitational force. They laugh it off as magic, despite the universal applicability of its equations to both local and celestial mechanics - but then they invoke words like “pressure” and “density” without being able to account for why their “pressure” has a downward vector in the absence of an external force field (the reason something above you exerts a pressure upon you, whether is that it’s being PULLED IN a DIRECTION) or why objects still fall INSIDE VACUUMS (don’t even bother, you will never get an answer). Of course they have to deny the existence of a gravitational central force because it is incompatible with a finite flat
disk, not to mention a cylinder which would pull you toward its center.

In the case of the really dumb ones it’s “because down is down, duh” - yes, clearly it’s gravitati theory that is “absurd” (as if things attracting one another based upon their mass were any weirder than the electromagnetic force - we can have magnetism but we can’t have gravity, no sir, that gravitational stuff is a priori absurd because ... because ... because modern materialists HATE the notion of action-at-a-distance as it interferes with their only conceivable notion of causation, that of Democritan billiard balls bumping into one another)

While I think Theosist is actually correct about that image, it's not conclusive.

I'm still waiting for you to provide an image of something that you believe shouldn't be visible due to curvature.

I've disputed the math. Refraction is usually a pretty negligible effect. I'll go dig up some of my old posts on the topic

This is just a straw man.

The Church doesn’t define any kind of reality. The Church defines true propositions about that reality which have been revealed by God, and what constitutes a “matter of faith” is not limited to things spiritual or only “essential to our salvation” - that’s Modernist  tripe of the kind that makes a nonsensical distinction between something being “theologically true” and otherwise! - no, it includes facts concerning human history, the nature of man, and cosmology. If the Bible states that the dimensions of Solomon’s Temple were x,y and z, the the Church has the power and authority to infallibly declare in this matter.

“Objective observation”, by the way, is a contradiction in terms, and the notion that a “physical reality” - by which really meant a theoretical model abstracted from sense experience, thus based not only upon uncertain data but upon  projecting conceptual fantasies into that data in order to postulate the existence of a world lying behind the content of sense experience - the notion that this process - of the blind grasping in the dark for a cat that might not exist at all - could take precedence over divine assurance of truth is preposterous.

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What you have said here is partially true, and partially false.
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The Church doesn't define reality that we can verify by objective observation. 
Things like the depth of the sea, or the limits of the sun's northern or southern declination each year, for example.
But the Church DOES define reality in spiritual matters, such as the Assumption of Our Lady body and soul into heaven.
So to say "the Church doesn't define any kind of reality" is incorrect.
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The dimensions of Solomon's temple is not something that can be verified because the temple no longer exists.
If the temple were still existing, the Church wouldn't declare that its dimensions are other than what can be observed.
Objective observation is its own reality, by the way.
There are those who deny the evidence of direct personal eyewitness. 
Thanks to Hegel, Locke, Hume, Comte, Kant, Marx, Nietzsche and their ilk, we have no shortage of deniers of observation.
I hope that's not what is infecting your perception!
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Regarding the flat-earthers' claim that the sun is close to earth, a few thousand miles, here are some observations:
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The sun would be further away at sunrise, closer at high noon, and again further away at sunset.
Therefore the sun would appear smaller at sunrise and sunset than it does at noon.
But that is not what we see, in fact.
Flat-earthers go so far as to FALSIFY videos of the sun by not using a solar filter, which makes the sun appear larger than it is.
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