You know the calculation the sun is 8 minutes away at the speed of light from earth which is the speed of gravity theoretically. So lets take a point right angles either side of the suns position right now and 8 minutes at the speed of light away. The deformation is some value x. Now roll forward one second. The sun has moved as we were initially right angles (the shortest distance) the distance to us must have increased slightly and so the gravity must drop by a small amount delta so we have x - delta. The key point here that point must not only distort it must undistort somehow.
Surely this apparent movement is due to the rotation of the Earth. The angle between sun and Earth does not change significantly. Obviously the fact that the Earth's orbit around the sun is not circular changes the angle through the year, but your 1 sec interval is not going to mark a significant difference to that.
