Wide Field Camera 3
Encyclopedia
Hubble Space Telescope
The Hubble Space Telescope is a space telescope that was carried into orbit by a Space Shuttle in 1990 and remains in operation. A 2.4 meter aperture telescope in low Earth orbit, Hubble's four main instruments observe in the near ultraviolet, visible, and near infrared...
's last and most technologically advanced instrument to take images in the visible spectrum. It was installed as a replacement for the Wide Field and Planetary Camera 2
Wide Field and Planetary Camera 2
The Wide Field and Planetary Camera 2 is a baby grand piano sized camera built by the Jet Propulsion Laboratory and formerly installed on the Hubble Space Telescope. It was installed by servicing mission 1 in 1993, replacing the telescope's original Wide Field and Planetary Camera...
during the first spacewalk of Space Shuttle mission STS-125
STS-125
STS-125, or HST-SM4 , was the fifth and final space shuttle servicing mission to the Hubble Space Telescope .Launch occurred on 11 May 2009 at 2:01 pm EDT...
on May 14, 2009.
Specifications
The instrument is designed to be a versatile cameraCamera
A camera is a device that records and stores images. These images may be still photographs or moving images such as videos or movies. The term camera comes from the camera obscura , an early mechanism for projecting images...
capable of imaging astronomical targets over a very wide wavelength range and with a large field of view. It is a fourth-generation instrument for Hubble. The instrument has two independent light paths: an optical channel that uses a pair of charge-coupled device
Charge-coupled device
A charge-coupled device is a device for the movement of electrical charge, usually from within the device to an area where the charge can be manipulated, for example conversion into a digital value. This is achieved by "shifting" the signals between stages within the device one at a time...
s (CCD) to record images from 200 nm to 1000 nm; and a near infrared detector array that covers the wavelength range from 800 to 1700 nm. Both channels have a variety of broad and narrow-band filters, as well as prisms
Prism (optics)
In optics, a prism is a transparent optical element with flat, polished surfaces that refract light. The exact angles between the surfaces depend on the application. The traditional geometrical shape is that of a triangular prism with a triangular base and rectangular sides, and in colloquial use...
and grism
Grism
A grism is a combination of a prism and grating arranged so that light at a chosen central wavelength passes straight through. The advantage of this arrangement is that one and the same camera can be used both for imaging and spectroscopy without having to be moved...
s, which enable wide-field, very-low-resolution spectroscopy that is useful for surveys. The optical channel covers the visible spectrum (380 nm to 780 nm) with high efficiency, and is also able to see into the near ultraviolet (down to 200 nm).
WFC3 features two UV/visible detecting CCDs, each 2048×4096 pixel
Pixel
In digital imaging, a pixel, or pel, is a single point in a raster image, or the smallest addressable screen element in a display device; it is the smallest unit of picture that can be represented or controlled....
s, and a separate IR detector of 1024×1024, capable of receiving infrared radiation up to 1700 nm.
Both detector focal planes were designed specifically for this camera. The optical channel covers a 164 by 164 arcsec (2.7 by 2.7 arcminute, about 8.5% of the diameter of the full moon as seen from Earth) field of view with 0.04 arcsec pixels. This field of view is comparable to the Wide Field and Planetary Camera 2
Wide Field and Planetary Camera 2
The Wide Field and Planetary Camera 2 is a baby grand piano sized camera built by the Jet Propulsion Laboratory and formerly installed on the Hubble Space Telescope. It was installed by servicing mission 1 in 1993, replacing the telescope's original Wide Field and Planetary Camera...
and is slightly smaller than the Advanced Camera for Surveys
Advanced Camera for Surveys
The Advanced Camera for Surveys is a third generation axial instrument aboard the Hubble Space Telescope . The initial design and scientific capabilities of ACS were defined by a team based at Johns Hopkins University. ACS was assembled and tested extensively at Ball Aerospace & Technologies Corp...
. The near infrared channel has a field of view of 135 by 127 arcsec (2.3 by 2.1 arcminutes) with 0.13 arcsec pixels, and has a much larger field of view than Near Infrared Camera and Multi-Object Spectrometer
Near Infrared Camera and Multi-Object Spectrometer
The Near Infrared Camera and Multi-Object Spectrometer is a scientific instrument for infrared astronomy, installed on the Hubble Space Telescope , operating from 1997 to 1999, and from 2002 to 2008...
, which it is designed to largely replace. The near infrared channel is a pathfinder for the future James Webb Space Telescope
James Webb Space Telescope
The James Webb Space Telescope , previously known as Next Generation Space Telescope , is a planned next-generation space telescope, optimized for observations in the infrared. The main technical features are a large and very cold 6.5 meter diameter mirror, an observing position far from Earth,...
. The IR channel is designed to lack sensitivity beyond 1700nm (as compared with the 2500nm limit for NICMOS) to avoid being swamped by dark current coming from the relatively warm HST structure. This allows WFC3 to be cooled using a thermoelectric cooler
Thermoelectric cooling
Thermoelectric cooling uses the Peltier effect to create a heat flux between the junction of two different types of materials. A Peltier cooler, heater, or thermoelectric heat pump is a solid-state active heat pump which transfers heat from one side of the device to the other side against the...
instead of carrying a consumable cryogen to cool the instrument.
The camera makes use of returned space hardware as the structure is built from the original Wide Field and Planetary Camera
Wide Field and Planetary Camera
The Wide Field/Planetary Camera was a camera installed on the Hubble Space Telescope until December 1993. It was one of the instruments on Hubble at launch, but its functionality was severely impaired by the defects of the main mirror optics which afflicted the telescope...
as well as the filter assembly. These were switched for the Wide Field and Planetary Camera 2
Wide Field and Planetary Camera 2
The Wide Field and Planetary Camera 2 is a baby grand piano sized camera built by the Jet Propulsion Laboratory and formerly installed on the Hubble Space Telescope. It was installed by servicing mission 1 in 1993, replacing the telescope's original Wide Field and Planetary Camera...
by the servicing mission STS-61
STS-61
STS-61 was the first Hubble Space Telescope servicing mission, and the fifth flight of the Space Shuttle Endeavour. The mission launched on 2 December 1993 from Kennedy Space Center in Florida. The mission restored the spaceborne observatory's vision, marred by spherical aberration, with the...
in December 1993.
WFC3 was originally conceived as an optical channel only; the near infrared channel was added later. WFC3 is intended to ensure that Hubble
Hubble Space Telescope
The Hubble Space Telescope is a space telescope that was carried into orbit by a Space Shuttle in 1990 and remains in operation. A 2.4 meter aperture telescope in low Earth orbit, Hubble's four main instruments observe in the near ultraviolet, visible, and near infrared...
retains a powerful imaging capability through to the end of its lifetime.
History
WFC3 has been in the planning since the Spring of 1998. It was built by a team of highly-experienced Hubble engineers and scientists drawn from many organizations, with leadership at Goddard Space Flight CenterGoddard Space Flight Center
The Goddard Space Flight Center is a major NASA space research laboratory established on May 1, 1959 as NASA's first space flight center. GSFC employs approximately 10,000 civil servants and contractors, and is located approximately northeast of Washington, D.C. in Greenbelt, Maryland, USA. GSFC,...
in Maryland
Maryland
Maryland is a U.S. state located in the Mid Atlantic region of the United States, bordering Virginia, West Virginia, and the District of Columbia to its south and west; Pennsylvania to its north; and Delaware to its east...
. WFC3 was constructed mostly at Goddard Space Flight Center and Ball Aerospace in Colorado. Various parts were built by contractors across the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
and the United Kingdom
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
.
The instrument was scheduled by NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...
to launch with STS-125 on 14 October 2008, but the mission was postponed due to additional repairs that were required. The mission launched on 11 May 2009 and the WFC3 was installed on 14 May.
See also
- Wide Field and Planetary CameraWide Field and Planetary CameraThe Wide Field/Planetary Camera was a camera installed on the Hubble Space Telescope until December 1993. It was one of the instruments on Hubble at launch, but its functionality was severely impaired by the defects of the main mirror optics which afflicted the telescope...
- Wide Field and Planetary Camera 2Wide Field and Planetary Camera 2The Wide Field and Planetary Camera 2 is a baby grand piano sized camera built by the Jet Propulsion Laboratory and formerly installed on the Hubble Space Telescope. It was installed by servicing mission 1 in 1993, replacing the telescope's original Wide Field and Planetary Camera...
- Cosmic Origins SpectrographCosmic Origins SpectrographThe Cosmic Origins Spectrograph is a science instrument that was installed on the Hubble Space Telescope during Servicing Mission 4 in May 2009. It is designed for ultraviolet spectroscopy of faint point sources with a resolving power of ≈1,550–24,000...
- Advanced Camera for SurveysAdvanced Camera for SurveysThe Advanced Camera for Surveys is a third generation axial instrument aboard the Hubble Space Telescope . The initial design and scientific capabilities of ACS were defined by a team based at Johns Hopkins University. ACS was assembled and tested extensively at Ball Aerospace & Technologies Corp...
- Near Infrared Camera and Multi-Object SpectrometerNear Infrared Camera and Multi-Object SpectrometerThe Near Infrared Camera and Multi-Object Spectrometer is a scientific instrument for infrared astronomy, installed on the Hubble Space Telescope , operating from 1997 to 1999, and from 2002 to 2008...
- Faint Object CameraFaint Object CameraThe Faint Object Camera was a camera installed on the Hubble Space Telescope from launch in 1990 until 2002. It was replaced by the Advanced Camera for Surveys.The camera was built by Dornier GmbH and was funded by the European Space Agency...
External links
- The WFC3 Web site at the Space Telescope Science Institute, which includes a description of the instrument and a link that compares the capabilities of various Hubble instruments.
- Hubble Space Telescope Team
- Hubble instrument comparisons