What is x-ray telescopes?

• X-ray telescopes have to be launched into orbit outside of the atmosphere or propelled to great heights by rockets and balloons due to atmospheric absorption.
• While telescopes carried aloft using rockets or satellites serve to detect softer radiation, balloon-borne telescopes may catch the more piercing (harder) X-rays.
• That sort of telescope must have a completely different design from a typical optical telescope.
• Since X-ray photons are so energetic, a typical reflector’s mirror wouldn’t be able to stop them from passing through.
• If X-rays are to be collected, they must bounce off a reflector at an extremely low angle.