The operation of gyroscopes also are independent of the shape of the earth.
Non-sequitur.
You might as well be talking about an Illodium Q-36 Explosive Space Modulator.
No, that's not even close to being a non-sequitur. I'm simply asking you to agree or disagree with my statement to the effect that directional gyroscopes have drift compensation that is a function of their latitude.
The point is that a gyroscopic instrument will suffer from both topple and drift due to transport and the earth's rotation - these effects would not be present on a non-rotating flat earth. I've shown both on this thread and on many others that aviation and maritime directional gyro devices have well documented drift compensation mechanisms. The drift wouldn't be there if the earth wasn't rotating, and the compensation wouldn't be linked to the sine of the latitude if the earth wasn't a sphere.
You might not understand this, and you might not like it, but it is true. I'm very happy to listen to any counter argument you may have, but all you've offered is variations on 'it's not true', which isn't very convincing.
The wealth of data indicates independent observations of Sigma Octantis cannot occur in South Africa, Argentina, and Australia at the same time.
What 'wealth of data' is that then?
I've previously showed you a reliable website that clearly shows that it can be dark in all thee places simultaneously, meaning the night sky, weather permitting of course, will be visible simultaneously. You are welcome to challenge this, if you wish, with evidence. You might argue that website is wrong - that's fine, let's see some proof. We can maybe look at some webcams or something along those lines to verify that it gets dark when predicted.
The other aspect to the argument is whether or not Sig Oct is always due south. Again, you're very welcome to put forward an argument, maybe supported by your hitherto undisclosed wealth of data, showing that Sig Oct is in fact not always true south. Of course, think carefully about that, because you've already agreed that celestial navigation is central to maritime travel, so which star charts do you think sailors use?
Come back when you got something substantive to offer, okay?
I've shown you lot's of evidence. You've completely ignored it, along with my questions. Let's see your 'wealth of evidence', and let's have some answers.
You already conceded that ocean going travel and airborne travel have not changed significantly since first embarkation.
Given both are done primarily by line of sight and have no real need for a spherical earth to happen, I think we are done here.
No, I agreed, broadly speaking, that navigational principals, in terms of celestial navigation, use of compasses, and globe-based maps, haven't changed that much since man first navigated the open seas. Your second sentence doesn't make any sense at all - it's not clear what you mean by 'line of sight', and good luck navigating across the southern pacific with a flat earth map. At least, I suppose, you won't run out of rations - it's nothing like as big as you think.