<P> 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 . </P> <P> 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 . </P>

Where do x-ray telescopes have to be placed in order to view objects in space