Darth Chronus said:

That's great Angel - maybe we should have something coming out of the ground that's projecting that holo - and when he turns to face Vader he can switch it off and the thing that's projecting it can retract back into the floor or something :)

There are greeblies on the top/front of the throne, just above the Emperor's head. Two identical things right next and right left of the center. These could well be made into holoprojectors.

As to the Endor moon being visible outside the window: The throne room is located on the top of a tower at the Death Star's north pole. The main window would face deep space and the space battle - not Endor. I think that one or both side windows could face Endor, though.