X-ray telescopes are designed to observe the x-ray region of the electromagnetic spectrum. X-rays from outer space cannot be observed from the ground due to absorption by the atmosphere, and so x-ray telescopes must be launched into orbit. Their mirrors require a very low angle of reflection (typically 10 arc-minutes to 2 degrees).[1] These are called glancing (or grazing) incidence mirrors. In 1952, Hans Wolter outlined three ways a telescope could be built using only this kind of mirror.[2][3]

Space-borne observatories and instruments

This list contains space-borne observatories as well as X-ray instruments as part of a larger mission, both past, present and in the proposal stage.

Name Launch Notes
Ariel 5 1974
Ariel 6 1979
ASCA 1993
ATHENA ~2031 Under development
AGILE 2007
Apollo Telescope Mount 1973 Part of Skylab, operated 1973-1974
Proposal, not selected for launch in 2019
ANS 1974
Astrosat 2015
BeppoSAX 1996
BBXRT 1990
Compton Gamma Ray Observatory 1991
Chandra X-ray Observatory 1999
Constellation-X Observatory
2008 proposal, merged into the International X-ray Observatory proposal
Copernicus 1972
Cos-B 1975
DXS 1993
Einstein Observatory 1978 originally HEAO-2
EP-WXT 2022
eROSITA 2019
Fermi 2008
Ginga 1987
Granat 1989
Gravity and Extreme Magnetism
2012 proposal
Hakucho 1979
Hard X-ray Modulation Telescope 2017 (HXMT) also known as Insight (Chinese: 慧眼)
HEAO-1 1977
HEAO 3 1979
High Energy Transient Explorer 1996
Hinode 2006
Hinotori 1981 Originally ASTRO-A
Hitomi 2016 Originally ASTRO-H
IXPE 2021
International X-ray Observatory
2012 proposal, now part of ATHENA
Max Valier Sat 2017
MAXI 2009
Neil Gehrels Swift Observatory 2004 Originally Swift Gamma-Ray Burst Mission[4]
NICER 2017
NuSTAR 2012
OAO-1 1966
Under development
OSO 7 1971
OSO 8 1975
ROSAT 1990
RXTE 1995
SAS-3 1975
Spektr-RG 2019
Suzaku 2005
Tenma 1983
Uhuru 1970
Vela 1963
XRISM 2023 Under development
Proposal, merged into the International X-ray Observatory proposal, now part of the ATHENA proposal
XMM-Newton 1999
XPoSat 2023 Planned, under development
Yohkoh 1991

High-altitude atmospheric observatories and instruments

Sometimes X-Ray observations are made from a near-space environment on sounding rockets or high-altitude balloons.


See also


  1. ^ Kulinder Pal Singh. "Techniques in X-ray Astronomy" (PDF).
  2. ^ Wolter, H. (1952). "Glancing Incidence Mirror Systems as Imaging Optics for X-rays". Annalen der Physik. 10: 94. Bibcode:1952AnP...445...94W. doi:10.1002/andp.19524450108.
  3. ^ Wolter, H. (1952). "A Generalized Schwarzschild Mirror System For Use at Glancing Incidence for X-ray Imaging". Annalen der Physik. 10: 286. Bibcode:1952AnP...445..286W. doi:10.1002/andp.19524450410.
  4. ^ "NASA Renames Swift Observatory in Honor of Late Principal Investigator". Space.com. 10 January 2018.