Editing Hubble Space Telescope (section)

=== Successors ===
{{further|James Webb Space Telescope}}
{{see also|List of proposed space observatories}}
{| class="wikitable" style="text-align:center; float:right; margin:10px"
| colspan="2" style="text-align:center;"|'''&nbsp;[[Visible spectrum]] range&nbsp;'''
|-
![[Color]]
|[[Wavelength]]
|-
| style="background:#ccb0f4;"|'''[[violet (color)|violet]]'''
|380–450&nbsp;nm
|-
| style="background:#b0b0f4;"|'''[[blue]]'''
|450–475&nbsp;nm
|-
| style="background:#b0f4f4;"|'''[[cyan]]'''
|476–495&nbsp;nm
|-
| style="background:#b0f4b0;"|'''[[green]]'''
|495–570&nbsp;nm
|-
| style="background:#f4f4b0;"|'''[[yellow]]'''
|570–590&nbsp;nm
|-
| style="background:#f4ccb0;"|'''[[orange (color)|orange]]'''
|590–620&nbsp;nm
|-
| style="background:#f4b0b0;"|'''[[red]]'''
|620–750&nbsp;nm
|}

[[File:Primary Mirror Size Comparison Between Webb and Hubble.webm|thumb|upright=1.0|right|Design, size, and mirror comparison between the James Webb Space Telescope and Hubble]]
There is no direct replacement to Hubble as an ultraviolet and visible light space telescope, because near-term space telescopes do not duplicate Hubble's wavelength coverage (near-ultraviolet to near-infrared wavelengths), instead concentrating on the further infrared bands. These bands are preferred for studying high redshift and low-temperature objects, objects generally older and farther away in the universe. These wavelengths are also difficult or impossible to study from the ground, justifying the expense of a space-based telescope. Large ground-based telescopes can image some of the same wavelengths as Hubble, sometimes challenge HST in terms of resolution by using [[adaptive optics]] (AO), have much larger light-gathering power, and can be upgraded more easily, but cannot yet match Hubble's excellent resolution over a wide field of view with the very dark background of space.<ref name=":3" /><ref name=":4" />

Plans for a Hubble successor materialized as the Next Generation Space Telescope project, which culminated in plans for the James Webb Space Telescope (JWST), the formal successor of Hubble.<ref name="SAOverview">{{cite web |url=http://www.scientificamerican.com/article.cfm?id=hubble-servicing-mission-shuttle |title=Last Dance with the Shuttle: What's in Store for the Final Hubble Servicing Mission |first=John |last=Matson |date=May 8, 2009 |work=Scientific American |access-date=May 18, 2009 |archive-date=December 26, 2010 |archive-url=https://web.archive.org/web/20101226170143/http://www.scientificamerican.com/article.cfm?id=hubble-servicing-mission-shuttle |url-status=live }}</ref> Very different from a scaled-up Hubble, it is designed to operate colder and farther away from the Earth at the L2 [[Lagrangian point]], where thermal and optical interference from the Earth and Moon are lessened. It is not engineered to be fully serviceable (such as replaceable instruments), but the design includes a docking ring to enable visits from other spacecraft.<ref>{{cite web |url=http://www.space.com/3833-nasa-adds-docking-capability-space-observatory.html |first=Brian |last=Berger |title=NASA Adds Docking Capability For Next Space Observatory |publisher=Space.com |date=May 23, 2007 |access-date=June 4, 2012 |archive-date=February 4, 2019 |archive-url=https://web.archive.org/web/20190204010427/https://www.space.com/3833-nasa-adds-docking-capability-space-observatory.html |url-status=live }}</ref> A main scientific goal of JWST is to observe the most distant objects in the universe, beyond the reach of existing instruments. It is expected to detect stars in the [[Timeline of the Big Bang|early Universe]] approximately 280&nbsp;million years older than stars HST now detects.<ref>{{cite press release |url=http://www.nasa.gov/mission_pages/hubble/science/farthest-galaxy.html |title=NASA's Hubble Finds Most Distant Galaxy Candidate Ever Seen in Universe |publisher=NASA |date=January 26, 2011 |access-date=June 4, 2012 |archive-date=May 2, 2017 |archive-url=https://web.archive.org/web/20170502061732/https://www.nasa.gov/mission_pages/hubble/science/farthest-galaxy.html |url-status=live }} [http://www.nasa.gov/images/content/512584main_i1105bw.jpg Visual representation] {{Webarchive|url=https://web.archive.org/web/20190605120204/https://www.nasa.gov/mission_pages/hubble/science/farthest-galaxy.html |date=June 5, 2019 }}.</ref> The telescope is an international collaboration between NASA, the European Space Agency, and the [[Canadian Space Agency]] since 1996,<ref>{{cite web |url=http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=33148 |archive-url=https://web.archive.org/web/20030821120829/http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=33148 |url-status=dead |archive-date=August 21, 2003 |title=ESA JWST Timeline |publisher=Sci.esa.int |date=June 30, 2003 |access-date=June 4, 2012}}</ref> and was launched on December 25, 2021, on an [[Ariane 5]] rocket.<ref>{{cite web |url=http://www.jwst.nasa.gov/launch.html |title=About Webb's Launch |publisher=NASA |access-date=November 4, 2006 |archive-date=June 16, 2019 |archive-url=https://web.archive.org/web/20190616111938/https://jwst.nasa.gov/launch.html |url-status=live }}</ref> Although JWST is primarily an infrared instrument, its coverage extends down to 600&nbsp;nm wavelength light, or roughly orange in the visible spectrum. A typical human eye can see to about 750&nbsp;nm wavelength light, so there is some overlap with the longest visible wavelength bands, including orange and red light.<ref>{{Cite web |title=FAQ |url=https://jwst.nasa.gov/content/about/faqs/faq.html |access-date=April 6, 2022 |website=jwst.nasa.gov |language=en |archive-date=July 23, 2019 |archive-url=https://web.archive.org/web/20190723142004/https://jwst.nasa.gov/content/about/faqs/faq.html |url-status=live }}</ref>

[[File:JWST-HST-primary-mirrors.svg|left|thumb|Hubble and JWST mirrors (4.0 m<sup>2</sup> and 25&nbsp;m<sup>2</sup> respectively)]]
A complementary telescope, looking at even longer wavelengths than Hubble or JWST, was the European Space Agency's [[Herschel Space Observatory]], launched on May 14, 2009. Like JWST, Herschel was not designed to be serviced after launch, and had a mirror substantially larger than Hubble's, but observed only in the [[far infrared]] and [[submillimeter astronomy|submillimeter]]. It needed helium coolant, of which it ran out on April 29, 2013.<ref name=bbc>{{cite web |url=https://www.bbc.co.uk/news/science-environment-21934520 |title=Herschel space telescope finishes mission |work=BBC News |first=Jonathan |last=Amos |date=April 29, 2013 |access-date=April 29, 2013 |archive-date=February 21, 2019 |archive-url=https://web.archive.org/web/20190221174104/https://www.bbc.co.uk/news/science-environment-21934520 |url-status=live }}</ref>

{| class=wikitable style="text-align:center; margin:10px"
|-
| colspan="8" style="text-align:center;"|'''Selected space telescopes and instruments'''<ref>{{cite web |url=http://herschel.jpl.nasa.gov/relatedMissions.shtml |title=JPL: Herschel Space Observatory: Related Missions |publisher=Herschel.jpl.nasa.gov |access-date=June 4, 2012 |archive-date=December 3, 2016 |archive-url=https://web.archive.org/web/20161203091854/https://herschel.jpl.nasa.gov/relatedMissions.shtml |url-status=live }}</ref>
|-
! Name !! Year || Wavelength || Aperture
|-
| Human eye || — || 0.39–0.75 μm || 0.005 m
|-
| [[Spitzer Space Telescope|Spitzer]] || 2003 || 3–180 μm || 0.85 m
|-
| Hubble STIS || 1997 || 0.115–1.03 μm || 2.4 m
|-
| Hubble WFC3 || 2009 || 0.2–1.7 μm || 2.4 m
|-
| [[Herschel Space Observatory|Herschel]] || 2009 || 55–672 μm || 3.5 m
|-
| [[James Webb Space Telescope|JWST]] || 2021 || 0.6–28.5 μm || 6.5 m
|}

Further concepts for advanced 21st-century space telescopes include the [[Large Ultraviolet Optical Infrared Surveyor]] (LUVOIR),<ref>"What Will Astronomy Be Like in 35 Years?". ''Astronomy''. August 2008.</ref> a conceptualized {{convert|8|to|16.8|m|in |abbr=off|sp=us}} optical space telescope that if realized could be a more direct successor to HST, with the ability to observe and photograph astronomical objects in the visible, ultraviolet, and infrared wavelengths, with substantially better resolution than Hubble or the Spitzer Space Telescope. The final planning report, prepared for the 2020 [[Astronomy and Astrophysics Decadal Survey]], suggested a launch date of 2039.<ref name=":1">{{cite web |date=August 26, 2019 |title=LUVOIR Mission Concept Study Final Report |url=https://www.luvoirtelescope.org/copy-of-design |access-date=May 24, 2021 |work=luvoirtelescope.org |publisher=[[NASA]] |archive-date=May 24, 2021 |archive-url=https://web.archive.org/web/20210524221618/https://www.luvoirtelescope.org/copy-of-design |url-status=live }}</ref> The Decadal Survey eventually recommended that ideas for LUVOIR be combined with the [[Habitable Exoplanet Imaging Mission|Habitable Exoplanet Observer]] proposal to devise a new, 6-meter flagship telescope that could launch in the 2040s.<ref name="NA-20211104">{{cite news |author=Staff |date=November 4, 2021 |title=New Report Charts Path for Next Decade of Astronomy and Astrophysics; Recommends Future Ground and Space – Telescopes, Scientific Priorities, Investments in Scientific Community |work=[[National Academies of Sciences, Engineering, and Medicine]] |url=https://www.nationalacademies.org/news/2021/11/new-report-charts-path-for-next-decade-of-astronomy-and-astrophysics-recommends-future-ground-and-space-telescopes-scientific-priorities-investments-in-scientific-community |url-status=live |accessdate=November 5, 2021 |archive-url=https://web.archive.org/web/20211105002202/https://www.nationalacademies.org/news/2021/11/new-report-charts-path-for-next-decade-of-astronomy-and-astrophysics-recommends-future-ground-and-space-telescopes-scientific-priorities-investments-in-scientific-community |archive-date=November 5, 2021}}</ref>

Existing ground-based telescopes, and various proposed [[Extremely Large Telescopes]], can exceed the HST in terms of sheer light-gathering power and diffraction limit due to larger mirrors, but other factors affect telescopes. In some cases, they may be able to match or exceed Hubble in resolution by using adaptive optics (AO). However, AO on large ground-based reflectors will not make Hubble and other space telescopes obsolete. Most AO systems sharpen the view over a very narrow field—[[Lucky imaging|Lucky Cam]], for example, produces crisp images just 10 to 20 arcseconds wide, whereas Hubble's cameras produce crisp images across a 150 arcsecond (2½ arcminutes) field. Furthermore, space telescopes can study the universe across the entire electromagnetic spectrum, most of which is blocked by Earth's atmosphere. Finally, the background sky is darker in space than on the ground, because air absorbs solar energy during the day and then releases it at night, producing a faint—but nevertheless discernible—[[airglow]] that washes out low-contrast astronomical objects.<ref name="Fienberg">{{cite news |last=Fienberg |first=Richard Tresch |date=September 14, 2007 |title=Sharpening the 200-Inch |work=Sky & Telescope |url=http://www.skyandtelescope.com/astronomy-news/sharpening-the-200-inch/ |url-status=live |access-date=July 1, 2008 |archive-url=https://web.archive.org/web/20180828035625/https://www.skyandtelescope.com/astronomy-news/sharpening-the-200-inch/ |archive-date=August 28, 2018}}</ref>

{{multiple images |total_width=550 |direction=horizontal |align=center |header=Left: image taken by Hubble (2017) vs Right: the image taken by Webb (2022)<ref name="NBC-20220712">{{cite news |last1=Chow |first1=Denise |last2=Wu |first2=Jiachuan |title=Photos: How pictures from the Webb telescope compare to Hubble's - NASA's $10 billion telescope peers deeper into space than ever, revealing previously undetectable details in the cosmos. |url=https://www.nbcnews.com/data-graphics/compare-photos-nasas-james-webb-space-telescope-hubble-space-telescope-rcna37875 |date=July 12, 2022 |work=[[NBC News]] |accessdate=July 23, 2022 |archive-date=July 15, 2022 |archive-url=https://web.archive.org/web/20220715193545/https://www.nbcnews.com/data-graphics/compare-photos-nasas-james-webb-space-telescope-hubble-space-telescope-rcna37875 |url-status=live }}</ref>
 |image1=NASA-HubbleSpaceTelescope-DeepField-2017.jpg |image2=Webb's First Deep Field (adjusted).jpg
 |footer=[[Webb's First Deep Field|Deep Field]] – [[Galaxy cluster]] [[SMACS J0723.3-7327]].<ref name="NASA-20220711">{{cite news |last=Garner |first=Rob |title=NASA's Webb Delivers Deepest Infrared Image of Universe Yet |url=https://www.nasa.gov/image-feature/goddard/2022/nasa-s-webb-delivers-deepest-infrared-image-of-universe-yet |date=July 11, 2022 |work=[[NASA]] |accessdate=July 23, 2022 |archive-date=July 12, 2022 |archive-url=https://web.archive.org/web/20220712000119/https://www.nasa.gov/image-feature/goddard/2022/nasa-s-webb-delivers-deepest-infrared-image-of-universe-yet/ |url-status=live }}</ref><ref name="NYT-20220711">{{cite news |last1=Overbye |first1=Dennis |last2=Chang |first2=Kenneth |last3=Tankersley |first3=Jim |title=Biden and NASA Share First Webb Space Telescope Image – From the White House on Monday, humanity got its first glimpse of what the observatory in space has been seeing: a cluster of early galaxies. |url=https://www.nytimes.com/2022/07/11/science/nasa-webb-telescope-images-livestream.html |date=July 11, 2022 |work=[[The New York Times]] |accessdate=July 23, 2022 |archive-date=July 12, 2022 |archive-url=https://web.archive.org/web/20220712005736/https://www.nytimes.com/2022/07/11/science/nasa-webb-telescope-images-livestream.html |url-status=live }}</ref><ref name="SA-202207">{{cite news |last=Pacucci |first=Fabio |title=How Taking Pictures of 'Nothing' Changed Astronomy - Deep-field images of "empty" regions of the sky from Webb and other space telescopes are revealing more of the universe than we ever thought possible |url=https://www.scientificamerican.com/article/how-taking-pictures-of-nothing-changed-astronomy1/ |date=July 15, 2022 |work=[[Scientific American]] |accessdate=July 23, 2022 |archive-date=July 16, 2022 |archive-url=https://web.archive.org/web/20220716023339/https://www.scientificamerican.com/article/how-taking-pictures-of-nothing-changed-astronomy1/ |url-status=live }}</ref>}}