Where is the thermal exhaust port on the Death Star?

[AnonymousRedShirtEnsign]

And how does that prevent an attack from above? This is one of the worst examples of engineering in all of scifi. Putting a grate every 100m or 1km along the vent duct would neutralize this weak spot. And how are a pair of fighter launched torpedos supposed to destroy a reactor that huge? I assume the walls of the reactor are tough enough to keep the power generation on the inside, and I'm sure it is substantially more powerful than a proton torpedo. I think it would have been much better for them to destroy something in the superlaser, so that when it fires, that energy is released into the station destroying it.

[Who is like God arbour]

Ah ha! Your picture, PDVD_058, gives us our answer. It seems that the port faces upwards, but is on a raised platform.

That's what I have feared.

I have not cognized, that this should be a raised platform, but now, that you say it, I can cognize it too. Before, I have not seen it this way. I have always thought, that, if the port would face upwards, the target circle in the middle of the screen would face upwards too and then it would be perspectively distorted. But it is a proper circle.

I try never to argue, that someone is a complete moron, unless this person is intentional displayed this way. I have always thought, that this is a low argument. Someone, who is able to build and maintain a starship would have to have necessarily some intelligence. If a person does something, that I don't understand, I try to think, that this person would have its reasons and try to rationalize it. That's why I have hoped, that the port doesn't face upwards. Now, there is no sense in doubting that the port face upwards any more, is there?

But now, I can't find a sensible reason, why the port should face upwards.
AnonymousRedShirtEnsign is absolutely correct. That is one of the worst examples of engineering.
As I have said already, a shaft from the surface of the death star direct down to its core is downright an invitation to attack at this point. There would be no super computer necessary to find this weakness.
The easiest way to use this weakness, would be to dive in on it and fire a smart torpedo or a rocket at an altitude of some kilometers, where the firing ship/fighter would still be out of range of the turbo lasers.
As was shown, the defence grid would not be able to intercept a high speed device. They wasn't even able to intercept the relatively slow fighters.

But what is most shocking for me, is, that the rebels too have to be complete morons. Their whole attack strategy was an absolute absurdity. There is no indication in the whole film, why an attack from above should have no chance of success. Why has no one asked in the briefing, why they couldn't attack from above? It seems to me, that no one has thought of it.

I think, the stupidity shown in this movie is nearly unique in science fiction (which is no comedy, parody, satire or otherwise supposed to be ludicrously). I at least don't know another example for such stupidity.

[AnonymousRedShirtEnsign]

I agree that we should assume competence and intelligence for characters unless they are clearly lacking (like Jar Jar). Therefore, there most be some reason why they didn't attack from above. I would suggest that it is either a physical barrier, or a shield of sorts, probably a directional or a theater one. We know there is a shield around the port so blasters won't do the trick (though how would you shoot blasters down the exhaust port from any direction but above?). We also know that the magnetic field around the Death Star interferes with the navigation of the fighters. So it's possible that the shield around the exhaust port, while it won't stop solid objects, will mess with their trajectories.

[Who is like God arbour]

[...] there most be some reason why they didn't attack from above.

I see no reason. That's my problem.

I would suggest that it is either a physical barrier, or a shield of sorts, probably a directional or a theater one. We know there is a shield around the port so blasters won't do the trick (though how would you shoot blasters down the exhaust port from any direction but above?).

It could be possible.

But such was never mentioned. In the novel, it was expressly said, that the port wasn’t particle-shielded. However, it was completely ray-shielded.
Other reasons, why the attackers have to approach the exhaust through the trench was not given.

Why would this not be explained at the pilots briefing? Why would no pilot ask, why they couldn't attack from above? The reason would be a vital information for this mission. When, if not at such a mission briefing, would a pilot ask such a question?

And it is to consider, that Darth Vader could shot at the, the exhaust port approaching fighters near the end of the trench and, after RED LEADER has fired of his torpedos, at him, what all must have happened in immediate vicinity of the thermal exhaust port.

He could also fire at Luke immediately before Luke has fired off his torpedos. And Han could fire at Vaders Wingman, although they all must have been in immediate vicinity of the thermal exhaust port.

After RED LEADER and Luke have fired of their torpedos, they must have left the trench in immediate vicinity of the thermal exhaust port, the first followed by Darth Vader.

We also know that the magnetic field around the Death Star interferes with the navigation of the fighters. So it's possible that the shield around the exhaust port, while it won't stop solid objects, will mess with their trajectories.

That could be. But a modern smart torpedo should be able to maintain its trajectory better than every human being. And a straight trajectory is easier to maintain than one, in which a correction at 90° is necessary.