Could it be that Obi didnt know about leia and when, as Luke was taking off, Yoda says "No, there is another." Then after the scene changes he says "Yeah, hes got a twin called leia" And tell Obi about it. this would exmplain why Obi says "That boy is our only hope" in ESB then knows all about leia in ROTJ. Just a theory...
yes. everyone has a different opinion on the subject of obi wan knowing about leia. hes saying that after luke took off for bespin, maybe yoda told obi wan about leia, and thats how obi wan knew in ep.6. i dont agree with it, but he can post whatever he wants, as long as it is polite and he stays on topic.
What I am trying to say is that the films actually provide all the info we need, the conversation between Obi and Yoda as Luke lifts off was, at least in my mind, aimed at the audience. Just another question we longed for to be answered when ROTJ came. ESB had quite a bunch of cliffhangers actually. Some floating questions for ROTJ, will Han be rescued, is Vader really Lukes father, who is the other hope.
But hey feel free to discuss whatever you want as long as it is within "the frames" of the films. I butt in whenever I feel it gets to much EU
also, if anyone has read the trilogy books where exar kun comes back to kill luke, with his new jedi learners, you will know that a scientist called Qwi Xux or something close to it designed the death star and it was built in the Maw, close to Kessel.
How can the Geonosians have come up with the death star? The planet is far from the Maw.