I was there for the first showing of Empire at 12 noon on May 21 1980. Saw it in Chicago in 70 MM at one of the last Cinemascope theaters in existence.

I can say that the establishing reveal of the Executor is well remembered by myself and my brother for we talked about that incessantly after the first several viewings. I ended up paying to watch Empire in 1980 & in second run during 1981 96 times.

My memory is vivid on what we understood that establishing overhead shot to convey. It was clearly a regular Star Destroyer as we deduced that from the others floating in the distance. We never assumed that was an establishing shot of something new.

Not until the shadow covers the focused SD did we think that there was something bigger.

Then there's the shot of the standard SD from behind and above it, some massive and huge wall of metal eclipsing space above it. Our jaws dropped at that point and the actual long shot of the Executor amidst the fleet had us awestruck.

For those of us in the audience, before we became uber Empire geeks as we are today - the initial shot in that sequence was never understood as something other than the same kind of ship that we were already familiar joining the others floating in the distance. It was not until the SHADOW moves over the standard SD that we perceived there was something else there that was much more gargantuan than what we assumed were the most massive ships in the galaxy barring the Death Star itself (remember we saw a SD swallow up the Tantive IV just three years earlier).

So I vote with the crowd that says the initial shot of the bridge conning tower is that of a regular Destroyer that we end up seeing get eclipsed in the shadow of the Executor.