The x-ray telescope.

An x-ray telescope is a telexcope that is designed to observe remote objects in the x-ray spectrum.
The most modern x-ray telescopes depend on:
- Lenses made of germanuim.
- The prime focus design, with mirrors made of iron.
- Grazing incidence optics.
- Achromatic lenses to keep the x-rays in focus.
- The cassegrain design, with mirrors made of lead.
The most modern x-ray telescopes are:

• The exosat, it was launched from 1983 to 1986, almost perpendicular to the moon.
• The Hard x-ray telescope, is observed from China, it's planned for launch between 2014 and 2016.
• Granat, it was launched in 1989 an  placed in higly eccentric four-day orbit.
• The focusing x-ray telescope was flown on the space shuttle Columbia.