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Wide Field and Planetary Camera 2

October 28, 2023

The Wide Field and Planetary Camera 2 (WFPC2) is a camera formerly installed on the Hubble Space Telescope. The camera was built by the Jet Propulsion Laboratory and is roughly the size of a baby grand piano. It was installed by servicing mission 1 (STS-61) in 1993, replacing the telescope's original Wide Field and Planetary Camera (WF/PC). WFPC2 was used to image the Hubble Deep Field in 1995, the Engraved Hourglass Nebula and Egg Nebula in 1996, and the Hubble Deep Field South in 1998. During STS-125, WFPC2 was removed and replaced with the Wide Field Camera 3 as part of the mission's first spacewalk on May 14, 2009. After returning to Earth, the camera was displayed briefly at the National Air and Space Museum and the Jet Propulsion Laboratory before returning to its final home at the Smithsonian's National Air and Space Museum.[1][2]

Brought back to Earth by the U.S. Space Shuttle, the WFPC is loaded for transport after display at JPL on its way to its final home at the National Air and Space Museum in 2010
Quantum efficiency of the CCD chip in the camera

Design edit

WFPC2 was built by NASA's Jet Propulsion Laboratory, which also built the predecessor WFPC camera launched with Hubble in 1990. WFPC2 contains internal corrective optics to fix the spherical aberration in the Hubble telescope's primary mirror.

The charge-coupled devices (CCDs) in the WFPC2 (designed at JPL and manufactured by Loral) detected electromagnetic radiation in a range from 120 nm to 1000 nm. This included the 380 nm to 780 nm of the visible spectrum, all of the near ultraviolet (and a small part of the extreme ultraviolet band) and most of the near-infrared band. The sensitivity distribution of these CCDs is roughly normal, with a peak around 700 nm and concomitantly very poor sensitivity at the extremes of the CCDs' operating range. WFPC2 featured four identical CCD detectors, each 800x800 pixels. Three of these, arranged in an L-formation, comprise Hubble's Wide Field Camera (WFC). Adjacent to them is the Planetary Camera (PC), a fourth CCD with different (narrower-focused) optics. This afforded a more detailed view over a smaller region of the visual field. WFC and PC images are typically combined, producing the WFPC2's characteristic stairstep image. When distributed as non-scientific JPEG files the PC portion of the image is shown with the same resolution as the WFC portions, but astronomers receive a raw scientific image package which presents the PC image in its native, higher detail.

To allow scientists to view specific parts of the electromagnetic spectrum the WFPC2 featured a rotating wheel which moves different optical filters into the lightpath (between the WFPC2's aperture and the CCD detectors). The 48 filter elements included:

  • A set of standard wideband photometric filters.
  • A graduated filter, featuring a wide range of very narrowband filters. By positioning the target object at a precise part of the field, the operator can use an accurately picked narrowband filter.
  • A number of narrowband optical filters tuned to the wavelengths of various atomic emission lines.

Performance edit

 
Picture of small section of the Carina Nebula created from images taken with Hubble's Wide Field Planetary Camera 2.[3]

As predicted, over the course of its mission the WFPC2 experienced degradation of the CCDs, resulting in defective ("hot") pixels. The telescope's operators performed monthly calibration tests to catalog these; with the WFPC's aperture closed a number of long exposures are taken, and pixels which differ significantly from near black are flagged. To avoid false positives caused by cosmic rays tripping a given pixel, the output of different calibration shots is compared. Pixels which are consistently "hot" are recorded, and astronomers who analyse raw WFPC2 images receive a list of these pixels. Typically, astronomers adjust their photo-processing software to ignore these bad pixels.

WFPC2 was largely superseded for broad-band imaging by the Advanced Camera for Surveys, installed during servicing mission 3B in 2002. However, the early 2007 failure of ACS resulted in WFPC2 returning to its role as Hubble's primary visible light camera. WFPC2 was removed from HST during Servicing Mission 4 in May 2009, for return to Earth and eventual museum display. It was replaced by Wide Field Camera 3, which features two UV/visible detecting CCDs, each 2048x4096 pixels, and a separate IR CCD of 1024 x 1024, capable of receiving infrared radiation up to 1700 nm.

See also edit

Other HST instruments :

WFPC2 images edit

References edit

  1. ^ ""The Camera that Saved Hubble" Coming to the Smithsonian". May 27, 2009. Archived from the original on October 13, 2010. Retrieved July 14, 2009.
  2. ^ . JPL / NASA. Archived from the original on February 7, 2012. Retrieved October 14, 2010.
  3. ^ "Return to the Carina Nebula". ESA/Hubble Picture of the Week. ESA/Hubble. Retrieved July 4, 2011.

External links edit

  • WFPC2 homepage and user's guide
  • NASA article explaining how color is built from multiple filtered images
  • the WFPC2 at ESA/Hubble
  • Images with the WFPC2 at ESA/Hubble

October 28, 2023
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The Wide Field and Planetary Camera 2 WFPC2 is a camera formerly installed on the Hubble Space Telescope The camera was built by the Jet Propulsion Laboratory and is roughly the size of a baby grand piano It was installed by servicing mission 1 STS 61 in 1993 replacing the telescope s original Wide Field and Planetary Camera WF PC WFPC2 was used to image the Hubble Deep Field in 1995 the Engraved Hourglass Nebula and Egg Nebula in 1996 and the Hubble Deep Field South in 1998 During STS 125 WFPC2 was removed and replaced with the Wide Field Camera 3 as part of the mission s first spacewalk on May 14 2009 After returning to Earth the camera was displayed briefly at the National Air and Space Museum and the Jet Propulsion Laboratory before returning to its final home at the Smithsonian s National Air and Space Museum 1 2 Brought back to Earth by the U S Space Shuttle the WFPC is loaded for transport after display at JPL on its way to its final home at the National Air and Space Museum in 2010Quantum efficiency of the CCD chip in the camera Contents 1 Design 2 Performance 3 See also 4 WFPC2 images 5 References 6 External linksDesign editWFPC2 was built by NASA s Jet Propulsion Laboratory which also built the predecessor WFPC camera launched with Hubble in 1990 WFPC2 contains internal corrective optics to fix the spherical aberration in the Hubble telescope s primary mirror The charge coupled devices CCDs in the WFPC2 designed at JPL and manufactured by Loral detected electromagnetic radiation in a range from 120 nm to 1000 nm This included the 380 nm to 780 nm of the visible spectrum all of the near ultraviolet and a small part of the extreme ultraviolet band and most of the near infrared band The sensitivity distribution of these CCDs is roughly normal with a peak around 700 nm and concomitantly very poor sensitivity at the extremes of the CCDs operating range WFPC2 featured four identical CCD detectors each 800x800 pixels Three of these arranged in an L formation comprise Hubble s Wide Field Camera WFC Adjacent to them is the Planetary Camera PC a fourth CCD with different narrower focused optics This afforded a more detailed view over a smaller region of the visual field WFC and PC images are typically combined producing the WFPC2 s characteristic stairstep image When distributed as non scientific JPEG files the PC portion of the image is shown with the same resolution as the WFC portions but astronomers receive a raw scientific image package which presents the PC image in its native higher detail To allow scientists to view specific parts of the electromagnetic spectrum the WFPC2 featured a rotating wheel which moves different optical filters into the lightpath between the WFPC2 s aperture and the CCD detectors The 48 filter elements included A set of standard wideband photometric filters A graduated filter featuring a wide range of very narrowband filters By positioning the target object at a precise part of the field the operator can use an accurately picked narrowband filter A number of narrowband optical filters tuned to the wavelengths of various atomic emission lines Performance edit nbsp Picture of small section of the Carina Nebula created from images taken with Hubble s Wide Field Planetary Camera 2 3 As predicted over the course of its mission the WFPC2 experienced degradation of the CCDs resulting in defective hot pixels The telescope s operators performed monthly calibration tests to catalog these with the WFPC s aperture closed a number of long exposures are taken and pixels which differ significantly from near black are flagged To avoid false positives caused by cosmic rays tripping a given pixel the output of different calibration shots is compared Pixels which are consistently hot are recorded and astronomers who analyse raw WFPC2 images receive a list of these pixels Typically astronomers adjust their photo processing software to ignore these bad pixels WFPC2 was largely superseded for broad band imaging by the Advanced Camera for Surveys installed during servicing mission 3B in 2002 However the early 2007 failure of ACS resulted in WFPC2 returning to its role as Hubble s primary visible light camera WFPC2 was removed from HST during Servicing Mission 4 in May 2009 for return to Earth and eventual museum display It was replaced by Wide Field Camera 3 which features two UV visible detecting CCDs each 2048x4096 pixels and a separate IR CCD of 1024 x 1024 capable of receiving infrared radiation up to 1700 nm See also editOther HST instruments Wide Field and Planetary Camera Former instrument on the Hubble Space Telescope Wide Field Camera 3 Astronomical camera on the Hubble Space Telescope Advanced Camera for Surveys Installed on HST March 2002 Cosmic Origins Spectrograph Instrument installed on the Hubble Space Telescope Faint Object Camera Installed on HST from 1990 to 2002 Faint Object Spectrograph former instrument on the Hubble Space TelescopePages displaying wikidata descriptions as a fallback Goddard High Resolution Spectrograph former spectrograph on the Hubble Space TelescopePages displaying wikidata descriptions as a fallback Near Infrared Camera and Multi Object Spectrometer scientific instrument on the Hubble Space TelescopePages displaying wikidata descriptions as a fallback Space Telescope Imaging Spectrograph Instrument on the Hubble Space TelescopeWFPC2 images edit nbsp Hubble Space Telescope WFPC2 image of the Hubble Deep Field showing the characteristic stairstep composition of WFPC2 images nbsp The Pillars of Creation within the Eagle Nebula nbsp WFPC 2 image in 1994 of M100 NGC 4321 nbsp NGC 604 in the Triangulum Galaxy nbsp Bok globules nbsp Part of Omega Centauri nbsp Egg NebulaReferences edit The Camera that Saved Hubble Coming to the Smithsonian May 27 2009 Archived from the original on October 13 2010 Retrieved July 14 2009 The Camera That Saved Hubble Leaves the Nest JPL NASA Archived from the original on February 7 2012 Retrieved October 14 2010 Return to the Carina Nebula ESA Hubble Picture of the Week ESA Hubble Retrieved July 4 2011 External links editWFPC2 homepage and user s guide NASA article explaining how color is built from multiple filtered images Wide Field Camera 3 NASA the WFPC2 at ESA Hubble Images with the WFPC2 at ESA Hubble WFPC2 Science Team Pages Retrieved from https en wikipedia org w index php title Wide Field and Planetary Camera 2 amp oldid 1141870682, wikipedia, wiki, book, books, library,

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