In the OT time frame is it common knowledge that Palpatine is, or was a Sith Lord (or has the Darth title) or did he and Vader hide it even after the events of ROTS? I see no reason to really hide it but also it seems in the OT time, in just 20 years, people have forgotten what a Jedi is or a lot about them. One guys calls the force a ancient religion. May guess it Palpatine and Vader destroyed recorders and did all they could to kill the history of the Jedi or even the force. I am sure the Emperor didn't allow it to be talked about in school.
Well, Tarkin says that Vader is "all that's left" of the Jedi/Sith "religion" with no mention of the Emperor. I would guess that Vader was upfront about his connection to and use of the Force, while Palpatine was far more secretive. Unless, of course, some source which I am unaware of contradicts this.
I don't get how they could not know that Palpatine was a Sith or at the very least a force user. Why else would Vader take commands from a gnarly old man? He could easily kill him and take over the Empire without any effort and it certianly would fit Vader's personality (this is from a normal Galactic Citizen's likely perspective)
In that case, why wouldn't Vader also undermine the authority of Tarkin, off him and take matters into his own hands? I think the general perception is that Vader is loyal to the Emperor, for reasons unknown; but, perhaps, it is speculated by some that the Emperor helped save his life, earning Vader a "life debt" he stays loyal to (which is true, from a certain POV). In other words, people accept there's a "history" between the two, and they leave it at that. Interesting question, but really, neither Vader nor the Emperor seem keen to acknowledge themselves as Sith in the OT, much less eager to go around bragging about it to others.
I doubt the wider galaxy knew about the Sith (or probably just that they had returned). Many probably assumed that Vader was simply the only Jedi who remained loyal to the Emperor. It could also be the fact that the Emperor has a charisma and 'personality cult' whilst Vader doesn't. It's much the same with Hitler and Himmler - the latter could have potentially eliminated the former, however given such a coup would create unrest within the state (especially given the rest of the government and military would have supported Hitler and wouldn't have wanted Himmler in command) no such coup occurred. So it could be assumed that Vader didn't launch a coup against the Emperor because it would fracture the Empire because the Empire is built around Palpatine.
I doubt the general public knew -- if Han's attitude is any indication, most people doubted that the Force even existed. The OT always gave me the impression that the average Joe thought the Jedi had been cons and that the idea of an "all-powerful" Force was a fringe belief of cultists. Also, don't forget that Yoda warns Luke to "not underestimate the powers of the Emperor" so I find it highly likely that Palpatine played up the image of a frail, harmless old man. It certainly helped him in ROTS.
Given what we are shown in the films, I feel it safe to say that the general public and ranks of the Empire have no idea he is a Sith. After all, he has to make up the lie about his face being "scarred and deformed." Had it ACTUALLY been scarred and deformed, I'm fairly certain he would have taken a moment after it happening to, I don't know, show SOME type of emotion instead of standing up like nothing happened. I'm also of the opinion that the films tell us, even if not openly, that Palpatine is over a thousand years old which makes everything make a lot more sense (heck, he HAS to be that old if the Jedi are aware of Darth Plagueis at all). He'd have no need to lie about his true appearance if he did not mind being seen as a Sith. Add to that what others have already said about the general attitude of some Imperials around Vader, and I think it goes even further to show that most do not have any idea. While some probably do, it's probably a very, very small minority.
Palpatine certainly gives off the impression of a Dark Wizard or Witch or something evil. Im sure there were rumors spun about Palpatine and his dark powers, but i don't think they thought of him as a force wielder but more of like dark magic and stuff. Various creepy tales to make urban legends that spread, yadda yadda.
I thought everyone already knew because you could so tell it was Ian playing both parts. His voice and mouth being the same (Sideous/Palps) was pretty obvious. That's just how I saw it of course...
I think by ROTJ, everyone may have known about Palpatine being a Sith since everyone overheard Vader calling him "Master" onboard the 2nd death star.
Thank you! But the Jedi aren't aware of Darth Plagueis at all. That's why Palpatine said the Plagueis "legend" was not a story the Jedi would tell.
I love that line. It's pretty funny, given the irony that the Jedi aren't aware of Palpatine's true nature, and the possibility the Jedi were witholding information from Anakin. And I agree, the Jedi didn't know of Plagueis, or the fact that the Sith were gradually biding their time behind the shadows... "The Sith have been extinct for a millenia". It's interesting to think about how the public saw the Sith. As someone else said, it seems to fit that the public thought Vader was the only Jedi to remain loyal. At first most would be seeing the Empire as welcome change. Peace and prosperity and the like. By ANH we've really seen what the Empire is cabable of. Besides wiping out the Jedi, after all their service to the people of the galaxy, and destroying planets, the image of Owen and Beru fried is ingrained in me from childhood. Hopefully this topic is expanded on in the future tv series. Probably one of the things that appealed to Anakin (IMO) was the title Lord. One of only two Sith Lords, and The Emperor seems to say it, such as in the security hologram, as a sign of some sort of status. That and it introduces Anakin as a Sith to both the audience and the Jedi, plus it sounds cool. One of my fave moments in ROTS is Anakin's response to orders to shut down the droids... "Very good, My Lord". It says a lot about why he turned, but I've gone way off-topic here.