I am trying to understand if the Landsat 7 satellite ETM+ orbit has any significant azimuth or if it could be assumed as 0° (as it is not a pointable sensor). I searched in the web but could not find any good answer so far. Zenith is supposed to be equal zero as Landsat images are always nadir. What about the azimuth? Would knowing the scene center coordinates (they're 46.036323 N and 10.456876 E) be of any help?
The image looks like a sort of isosceles trapezoid, with the major basis towards the North (as I would expect for the Northern Hemisphere). It is also tilted differently from south to North (as I also would expect).
I would appreciate any help, thanks in advance.
One question arised while I was trying to solve my task. The metadata file of Landsat provides coordinates of the four image corners. Anyway they refer to the black background. The azimuth is intended to be calculated through these corners or the corners of the "real"-non-background image? And why do I have to use latitude rather than longitude? Is it not better to use longitude? I thought to use (for instance) the right corners, subctracting the longitudes of them (e.g. upper right long-lower right long) and obtain what I was looking for in terms of degrees, does it make sense for you? Here is an image showing a part of Landsat paths in a Worldwide Reference System (descending orbit) and my Landsat scene. RS is geographic, WGS84. According to this what I should looking at is the non-background image.