X-ray telescope
An X-ray telescope (XRT) is a telescope that is designed to observe remote objects in the X-ray spectrum. X-rays are absorbed by the Earth's atmosphere, so instruments to detect X-rays must be taken to high altitude by balloons, sounding rockets, and 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 X-ray telescopes on satellites are compounded of multiple small detector-telescope systems whose capabilities add up or complement each other, and additional fixed or removable elements[1][2] (filters, spectrometers) that add functionalities to the instrument.
Active X-ray observatory satellites[edit]
Satellites in use today include ESA's XMM-Newton observatory (low to mid energy X-rays 0.1-15 keV), NASA's Swift observatory, Chandra observatory and IXPE telescope. JAXA has launched the XRISM telescope, while ISRO has launched Aditya-L1 and XPoSat.
The GOES 14 spacecraft carries on board a Solar X-ray Imager to monitor the Sun's X-rays for the early detection of solar flares, coronal mass ejections, and other phenomena that impact the geospace environment.[5] It was launched into orbit on June 27, 2009, at 22:51 GMT from Space Launch Complex 37B at the Cape Canaveral Air Force Station.
The Chinese Hard X-ray Modulation Telescope was launched on June 15, 2017 to observe black holes, neutron stars, active galactic nuclei and other phenomena based on their X-ray and gamma-ray emissions.[6]
The Lobster-Eye X-ray Satellite was launched on 25 July 2020 by CNSA making it is the first in-orbit telescope to utilize the lobster-eye imaging technology of ultra-large field of view imaging to search for dark matter signals in the x-ray energy range.[7] Lobster Eye Imager for Astronomy was launched on 27 July 2022 as a technology demonstrator for Einstein Probe, launched on January 9, 2024, dedicated to time-domain high-energy astrophysics.[8] The Space Variable Objects Monitor observatory launched on 22 June 2024 is directed towards studying the explosions of massive stars and analysis of gamma-ray bursts.[9]
A soft X-ray solar imaging telescope is on board the GOES-13 weather satellite launched using a Delta IV from Cape Canaveral LC37B on May 24, 2006.[10] However, there have been no GOES 13 SXI images since December 2006.
The Russian-German Spektr-RG carries the eROSITA telescope array as well as the ART-XC telescope. It was launched by Roscosmos on 13 July 2019 from Baikonur and began collecting data in October 2019.