Editing Hubble Space Telescope (section)

=== Initial instruments ===
{{Main|Wide Field and Planetary Camera|Goddard High Resolution Spectrograph|High Speed Photometer|Faint Object Camera|Faint Object Spectrograph}}
[[File:HubbleExploded edit 1.svg|thumb|upright=1.8|right|[[Exploded view]] of the Hubble Space Telescope]]

When launched, the HST carried five scientific instruments: the Wide Field and Planetary Camera (WF/PC), Goddard High Resolution Spectrograph (GHRS), High Speed Photometer (HSP), Faint Object Camera (FOC) and the Faint Object Spectrograph (FOS). WF/PC used a radial instrument bay, and the other four instruments were each installed in an axial instrument bay.<ref name="CP-2244"/>

WF/PC was a high-resolution imaging device primarily intended for optical observations. It was built by NASA's [[Jet Propulsion Laboratory]], and incorporated a set of 48 [[filter (optics)|filters]] isolating [[spectral line]]s of particular astrophysical interest. The instrument contained eight [[charge-coupled device]] (CCD) chips divided between two cameras, each using four CCDs. Each CCD has a resolution of 0.64 megapixels.<ref name=wfpc2>{{cite web|url=https://esahubble.org/about/general/instruments/wfpc2/|title=Hubble's Instruments: WFPC2 Wide Field Planetary Camera 2|website=esahubble.org|publisher=[[European Space Agency]]|access-date=April 7, 2022|archive-date=April 7, 2022|archive-url=https://web.archive.org/web/20220407073748/https://esahubble.org/about/general/instruments/wfpc2/|url-status=live}}</ref> The wide field camera (WFC) covered a large angular field at the expense of resolution, while the planetary camera (PC) took images at a longer effective [[focal length]] than the WF chips, giving it a greater magnification.<ref name="CP-2244">{{cite tech report|title=The Space Telescope Observatory|number=CP-2244|publisher=NASA|editor-first=Donald N. B.|editor-last=Hall|url=https://ntrs.nasa.gov/citations/19820025420|date=1982|access-date=April 7, 2022|archive-date=April 7, 2022|archive-url=https://web.archive.org/web/20220407073748/https://ntrs.nasa.gov/citations/19820025420|url-status=live}}</ref>

The [[Goddard High Resolution Spectrograph]] (GHRS) was a [[spectrograph]] designed to operate in the ultraviolet. It was built by the Goddard Space Flight Center and could achieve a [[spectral resolution]] of 90,000.<ref>{{cite journal |author=Brandt |first1=J. C. |last2=Heap |first2=S. R. |last3=Beaver |first3=E. A. |last4=Boggess |first4=A. |last5=Carpenter |first5=K. G. |last6=Ebbets |first6=D. C. |last7=Hutchings |first7=J. B. |last8=Jura |first8=M. |last9=Leckrone |first9=D. S. |date=1994 |title=The Goddard High Resolution Spectrograph: Instrument, goals, and science results |journal=Publications of the Astronomical Society of the Pacific |volume=106 |pages=890–908 |bibcode=1994PASP..106..890B |doi=10.1086/133457 |doi-access=|s2cid=120181145 }}</ref> Also optimized for ultraviolet observations were the FOC and FOS, which were capable of the highest spatial resolution of any instruments on Hubble. Rather than CCDs, these three instruments used [[photon]]-counting [[digicon]]s as their detectors. The FOC was constructed by ESA, while the [[University of California, San Diego]], and [[Martin Marietta Corporation]] built the FOS.<ref name="CP-2244"/>

The final instrument was the HSP, designed and built at the [[University of Wisconsin–Madison]]. It was optimized for visible and ultraviolet light observations of [[variable star]]s and other astronomical objects varying in brightness. It could take up to 100,000 measurements per second with a [[photometry (astronomy)|photometric]] accuracy of about 2% or better.<ref>Bless, R. C.; Walter, L. E.; White R. L. (1992) ''High Speed Photometer Instrument Handbook'' v 3.0 STSci.</ref>

HST's guidance system can also be used as a scientific instrument. Its three [[Fine guidance sensor|Fine Guidance Sensor]]s (FGS) are primarily used to keep the telescope accurately pointed during an observation, but can also be used to carry out extremely accurate [[astrometry]]; measurements accurate to within 0.0003 arcseconds have been achieved.<ref>{{cite conference |author=Benedict |first1=G. Fritz |last2=McArthur |first2=Barbara E. |date=2005 |editor-last=Kurtz |editor-first=D. W. |title=High-precision stellar parallaxes from Hubble Space Telescope fine guidance sensors |url=https://pdfs.semanticscholar.org/ce07/0e358a8f3ed7a8bb7b470fc2986c8833d3f0.pdf |conference=IAU Colloquium #196 |publisher=Cambridge University Press |pages=333–346 |bibcode=2005tvnv.conf..333B |doi=10.1017/S1743921305001511 |archive-url=https://web.archive.org/web/20200227131024/https://pdfs.semanticscholar.org/ce07/0e358a8f3ed7a8bb7b470fc2986c8833d3f0.pdf |archive-date=February 27, 2020 |work=Transits of Venus: New Views of the Solar System and Galaxy |s2cid=123078909 |url-status=dead}}</ref>