Conventional telescope designs require reflection or refraction in a manner that does not work well for X-rays.
X-ray mirrors can be built, but only if the angle from the plane of reflection is very low (typically 10 arc-minutes to 2 degrees).
In 1952, Hans Wolter outlined three ways a telescope could be built using only this kind of mirror.
[6] Wolter's key innovation was that by using two mirrors it is possible to create a telescope with a usably wide field of view.
In contrast, a grazing incidence telescope with just one parabolic mirror could focus X-rays, but only very close to the centre of the field of view.