"But wait, how can you perform telescopic observations in X-rays? They tend to penetrate matter (including telescopes), right?" Correct, normal optics would no

"But wait, how can you perform telescopic observations in X-rays? They tend to penetrate matter (including telescopes), right?" Correct, normal optics would not work. X-ray telescopes use grazing incidence mirror arrangement (Wolter telescope [1] [2]). [1] https://en.wikipedia.org/wiki/Wolter_telescope https://en.wikipedia.org/wiki/Wolter_telescope [2] https://en.wikipedia.org/wiki/EROSITA https://en.wikipedia.org/wiki/EROSITA