They're doing an amazing job in the trailers with the shots building up the Death Star's astronomical size.
Except that, unless they're retconning the Death Star I's size to be rather larger than it was originally (or the planet it's orbiting is absurdly tiny), they've got it all wrong.
The Death Star I was 120km in diameter (
source), so if it was orbiting Earth at just the edge of space directly overhead (so 160km above the surface, given the Karman line at 100km), it would indeed be quite imposing, filling 41 degrees of the sky (
source). 41 degrees is about a quarter of the way from one horizon to the other, so to imagine how it would look, point one arm straight up and the other straight out to your side. Now move your arm that's out to the side so it's halfway from where it was to straight up, and then move it again so it's halfway from
there to straight up. Now move your straight-up arm so it's at the same angle on the other side. The Death Star would fill that space, approximately.
Or, even simpler, imagine holding a large (16" diameter) pizza at arm's length above your head--that's about what the Death Star would look like. Except less tasty.
So, sure, the shot in the trailer at 60seconds seems like it could be 41 degrees or less, so it's accurate, right?
Not quite.
Notice that the death star in the image is not directly overhead. It is, in fact, more than halfway below the horizon. So, it has to be farther away--a lot farther away.
For the sake of simplicity, let's assume it's still 160km above the ground, right at the edge of space. Let's also, for ease of calculation, determine how big the Death Star would appear when it's halfway above the horizon, since that should be
bigger than it is in the trailer, since it could be closer. Let's also start the calculations assuming an observer at ground level, even thought the above shot is clearly quite high in the air, since again, this assumption will bring the distance closer.
At that point, it becomes a simple horizon distance calculation--the observer, in this case, is at the horizon distance from the Death Star's altitude.
That means the Death Star would need to be 1438km away in the "observer on ground, halfway over the horizon" simplified case--and in that case, it would only cover about 6 degrees -- only about 12 times the size of the Sun. Still impressive, but nowhere near as huge as shown in the trailer.
In conclusion,
http://tvtropes.org/pmwiki/pmwiki.php/Main/ScifiWritersHaveNoSenseOfScale
As an aside, I find it kind of disappointing that they didn't just build a digital model of the situation and use that--instead, they evidently just had the 2d artists draw what "looked impressive" and left it at that...