Editing High Speed Photometer (section)

{{Short description|Scientific instrument on the Hubble Space Telescope}}
[[File:STS061-93-031 HST rendezvous.jpg|thumb|STS-61 rendezvous with Hubble Space Telescope to replace various items including the High Speed Photometer]]
The '''High Speed Photometer''' ('''HSP''') is a [[Measuring instrument|scientific instrument]] formerly installed on the [[Hubble Space Telescope]]. The HSP was designed to measure the brightness and polarity of rapidly varying celestial objects. It could observe in [[ultraviolet]], [[visible light]], and near [[infrared]] at a rate of one measurement per 10 [[microseconds]]. The design was novel in that despite being able to view through a variety of filters and apertures, it had no moving parts "except for electrons" as principal investigator Prof. Robert Bless was fond of saying.  Filter and aperture selection was accomplished using image dissector tubes and the HST pointing system.<ref name="Instruments">{{Cite web|url=https://www.spacetelescope.org/about/general/instruments/hsp/|title=Hubble's Instruments: HSP – High Speed Photometer|last=|website=www.spacetelescope.org |language=en|access-date=2017-02-23}}</ref> It was functional from launch in 1990 until it was removed at the end of 1993, and it helped diagnose an issue with the Hubble's primary mirror.<ref name="Contributions">{{Cite web|url=http://news.wisc.edu/wisconsin-contributions-helped-hubble-space-telescope-soar/|title=Wisconsin contributions helped Hubble Space Telescope soar|website=news.wisc.edu|language=en-US|access-date=2017-02-23}}</ref>

The HSP was one of the instruments on Hubble at launch. Its primary mission was compromised by the optical problems with the telescope, although some projects were still successful.  During the [[STS-61|first servicing mission]], in December 1993, it was replaced by the [[Corrective Optics Space Telescope Axial Replacement]] (COSTAR), which corrected the optical problem for the remaining instruments.

The principal investigator for the instrument was Dr. Robert C. Bless.<ref>{{Cite web|url=http://www.sal.wisc.edu/HSP/|title=High Speed Photometer|website=www.sal.wisc.edu|access-date=2017-02-23}}</ref> Dr. Bless died in 2015, and his contributions to the Hubble Space Telescope and the HSP instrument were noted in news media.<ref name="Contributions" /> He worked at the [[University of Wisconsin–Madison]], and the HSP was the lightest and least expensive of the launch instruments.<ref name="Contributions" />

The HSP instrument is located as of 2015 at the University of Wisconsin-Madison's [[Space Place]].<ref name="Contributions" />

It was scientifically active during its period of use, an example of observations taken with the instrument is ultraviolet [[Photometry (astronomy)|photometry]] of [[Nova Cygni 1992]].<ref>[http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1994ApJ...424L..45T&db_key=AST ''Ultraviolet Photometry of Nova Cygni 1992 Obtained with the High Speed Photometer'' 1994]</ref>