If a photon transverse the path in such a way that it make moves in(x¹ - y¹) plane making an angle of Φwith x_axis of gram s. Prove that for the frame s ux² + uy² = c² where s¹ is moving with velocity v relative to s. ​

The largest observatory complex in the world is on mauna kea, the tallest mountain on earth. what are some factors astronomers consider when selecting an observatory site? don’t forget practical ones. should astronomers, for example, consider building an observatory on denali (mount mckinley) or mount everest?