Focusing x-rays is not impossible but very difficult. If you look at x-ray telescopes such as Chandra or XMM-Newton you'll notice they have extremely long, very

Focusing x-rays is not impossible but very difficult. If you look at x-ray telescopes such as Chandra or XMM-Newton you'll notice they have extremely long, very high aspect ratio mirrors. This is because x-rays generally only reflect at grazing angles. At high enough energies you can use particle physics equipment because gamma rays will produce electron-positron pairs on impact (allowing you to then track their trajectories and work backwards to determine the direction of the gamma rays). Such equipment is enormously expensive and also very large so it's not particularly practical.