Wiktionary
n. (context astronomy English) An instrument that detects X-rays originating from outside the Earth's atmosphere.
Wikipedia
An X-ray telescope (XRT) is a telescope that is designed to observe remote objects in the X-ray spectrum. In order to get above the Earth's atmosphere, which is opaque to X-rays, X-ray telescopes must be mounted on high altitude rockets, balloons or artificial satellites.
The basic elements of the telescope are the optics (focusing or collimating), that collects the radiation entering the telescope, and the detector, on which the radiation is collected and measured. A variety of different designs and technologies have been used for these elements.
Many of the existing telescopes on satellites are compounded of multiple copies or variations of a detector-telescope system, whose capabilities add or complement each other and additional fixed or removable elements (filters, spectrometers) that add functionalities to the instrument.
Usage examples of "x-ray telescope".
To determine whether astronomical objects emit such short wavelengths of light, an X-ray telescope must be carried aloft.
The giant X-ray telescope anchored in the dust of the Korolev Basin revolved in its heavy turret to take an optical bearing on it.
The X-ray telescope we just orbited was a direct spin-off of H-Bomb research.
Glancing down at the monitor displays, she saw that she was looking at a real-time image of the solar x-ray telescope.
It was akin to an X-ray telescope which sees exploding stars where an ordinary telescope only sees dust and darkness.