Yeah that shot is rear projection but the planet does not look like Aldetaan. And that is the reason people keep changing it and disliking it It’s totally different. Some old slide projector probably with only 1 slide loaded. I can’t imagine some cassete loaded animation on this considering crew members were shouting “Bang!” This was more likely some sort of aide for the actors nothing more.

In the radio drama it plays out like a reveal which is i am sure probably based off the script.

It’s also posdible this was eakmarked as Yavin 4 it looks much similar to the mcQuarrie matte painting than Alderaan. The final battle was going to be at Alderaan at one time too. So Alderaam art became yavin 4?

Anyway having the planet on the screen at that point makes zero sense and it degrades the characters into imbeciles.

But when the planet is on screen there is another mistake… If the planet is travelling from right to left the stars should be going left to right. Then it will look correct rather than a flat image it will be 3D but with 2D images.