In X-ray astronomy we often use Wolter Type 1 optics based on grazing incidence. These can be made with various techniques depending on the spatial accuracy (po

In X-ray astronomy we often use Wolter Type 1 optics based on grazing incidence. These can be made with various techniques depending on the spatial accuracy (point spread function) required, e.g. foils for low accuracy or even stacked silicon wafers planned for the Athena telescope. The effective area of the telescope is smaller than the physical mirror size as everything has to be reflected at grazing incidence. We often use CCDs to detect the X-rays.