Fine Guidance Sensor (HST)

Last updated
From the center to outer edge of the FGS field of view is 14.1 arcminutes This is a diagram of the field of view of each Hubble Space Telescope instrument, including the three FGS instruments (FGS field of view(s) highlighted in yellow) Hubble OTA FOVfgsyellow.png
From the center to outer edge of the FGS field of view is 14.1 arcminutes This is a diagram of the field of view of each Hubble Space Telescope instrument, including the three FGS instruments (FGS field of view(s) highlighted in yellow)
A Fine Guidance Sensor being refurbished between servicing missions SM3A and SM4 238888main FGS.JPG
A Fine Guidance Sensor being refurbished between servicing missions SM3A and SM4
A fine guidance sensors in space on STS Servicing Mission 2 in 1997 Fgs sm.jpg
A fine guidance sensors in space on STS Servicing Mission 2 in 1997

Fine Guidance Sensor (FGS) for the Hubble Space Telescope is a system of three instruments used for pointing the telescope in space, and also for astrometry and its related sciences. [2] To enable aiming the telescope at a specific spot in the sky, each FGS combines optics and electronics. [2] There are three Hubble FGS, and they have been upgraded over the lifetime of the telescope by crewed Space Shuttle missions. [3] The instruments can support pointing of 2 milli-arc seconds (units of degree). [4] The three FGS are part of the Hubble Space Telescope's Pointing Control System, aka PCS. [5] The FGS function in combination with the Hubble main computer and gyroscopes, with the FGS providing data to the computer as sensors which enables the HST to track astronomical targets. [6]

Contents

The FGS can be used to locate something in space, and then lock-on to it. [7] It can provide the movements the telescope must make to keep the object in view, for the main instruments to record data on. [8]

The FGS were originally made by the optics company Perkin-Elmer, and as removable and repairable instruments it has been possible to refurbish them over the lifetime of the telescope. [8] The first replacement FGS was installed in 1997, swapping out FGS1. [5]

In May 2009, on STS-125 a FGS was replaced during the mission to the Hubble telescope by the Space Shuttle. [9] The astronaut crew performed an EVA (spacewalk) to service the FGS and other components on the telescope in Earth orbit. [9] This was the SM4 mission. [6]

An example of astrometry science with the Hubble FGS system is observations of the Low-Mass Binary star system L722-22. [10] Observations were taken of the system in 1990s, and the data helped determine the mass of each of the components of L722-22, which is also known as LHS 1047 and GJ 1005. [10]

The FGS are white-light shearing interferometers. [5] The FGS weigh 220 kg (485 lb) and have dimensions of roughly 0.5 m × 1.0 m × 1.6 meters. [11]

Observations

The smallest Kuiper belt object (KBO) yet detected at that time was discovered in 2009 by poring over data from the Hubble Space Telescope's fine guidance sensors. [12] They detected a transit of an object against a distant star, which, based on the duration and amount of dimming, was calculated to be a KBO about 1,000 meters (3,200 ft) in diameter. [12] It has been suggested that the Kepler observatory may be able to detect objects in the Oort cloud by their occultation of background stars, [13] and the Whipple proposal would also try to use this concept.

A Hubble FGS has also been used for astrometry, tracking the movement of different stars. [14] This ability was used for exoplanet research, where the motion of the star caused by the movement of planets around it was detected. [14] Hubble was used via the FGS sensors to detect the motion of star caused by an exoplanet orbiting it. [15] The effect on the red dwarf Gliese 876's by companion Gliese 876b was measured. [15]

FGS was used to study double-star systems (aka binary star systems) and to measure distances to astronomical bodies. [15]

FGS has also been used to observe asteroids and calculate their size. [16] Asteroids studied include (63) Ausonia, (15) Eunomia, (43) Ariadne, (44) Nysa, and (624) Hektor. [16]

See also

Related Research Articles

<span class="mw-page-title-main">Astrometry</span> Branch of astronomy involving positioning and movements of celestial bodies

Astrometry is a branch of astronomy that involves precise measurements of the positions and movements of stars and other celestial bodies. It provides the kinematics and physical origin of the Solar System and this galaxy, the Milky Way.

<span class="mw-page-title-main">Kuiper belt</span> Area of the Solar System beyond the planets, comprising small bodies

The Kuiper belt is a circumstellar disc in the outer Solar System, extending from the orbit of Neptune at 30 astronomical units (AU) to approximately 50 AU from the Sun. It is similar to the asteroid belt, but is far larger—20 times as wide and 20–200 times as massive. Like the asteroid belt, it consists mainly of small bodies or remnants from when the Solar System formed. While many asteroids are composed primarily of rock and metal, most Kuiper belt objects are composed largely of frozen volatiles, such as methane, ammonia, and water. The Kuiper belt is home to most of the objects that astronomers generally accept as dwarf planets: Orcus, Pluto, Haumea, Quaoar, and Makemake. Some of the Solar System's moons, such as Neptune's Triton and Saturn's Phoebe, may have originated in the region.

<span class="mw-page-title-main">Very Large Telescope</span> Telescope in the Atacama Desert, Chile

The Very Large Telescope (VLT) is an astronomical facility operated since 1998 by the European Southern Observatory, located on Cerro Paranal in the Atacama Desert of northern Chile. It consists of four individual telescopes, each equipped with a primary mirror that measures 8.2 meters in diameter. These optical telescopes, named Antu, Kueyen, Melipal, and Yepun, are generally used separately but can be combined to achieve a very high angular resolution. The VLT array is also complemented by four movable Auxiliary Telescopes (ATs) with 1.8-meter apertures.

<span class="mw-page-title-main">First light (astronomy)</span> Term in astronomy for the first time a telescope is used to look at the Universe

In astronomy, first light is the first use of a telescope to take an astronomical image after it has been constructed. This is often not the first viewing using the telescope; optical tests will probably have been performed to adjust the components.

<span class="mw-page-title-main">Great Observatories program</span> Series of NASA satellites

NASA's series of Great Observatories satellites are four large, powerful space-based astronomical telescopes launched between 1990 and 2003. They were built with different technology to examine specific wavelength/energy regions of the electromagnetic spectrum: gamma rays, X-rays, visible and ultraviolet light, and infrared light.

<span class="mw-page-title-main">44 Nysa</span> Main-belt asteroid

44 Nysa is a large and very bright main-belt asteroid, and the brightest member of the Nysian asteroid family. It is classified as a rare class E asteroid and is probably the largest of this type.

<span class="mw-page-title-main">Kepler space telescope</span> NASA space telescope for exoplanetology (2009–2018)

The Kepler space telescope is a defunct space telescope launched by NASA in 2009 to discover Earth-sized planets orbiting other stars. Named after astronomer Johannes Kepler, the spacecraft was launched into an Earth-trailing heliocentric orbit. The principal investigator was William J. Borucki. After nine and a half years of operation, the telescope's reaction control system fuel was depleted, and NASA announced its retirement on October 30, 2018.

<span class="mw-page-title-main">Far Ultraviolet Spectroscopic Explorer</span> NASA satellite of the Explorer program

Far Ultraviolet Spectroscopic Explorer represented the next generation, high-orbit, ultraviolet space observatory covering the wavelength range of 90.5–119.5 nanometre (nm) of the NASA operated by the Johns Hopkins University Applied Physics Laboratory. FUSE was launched on a Delta II launch vehicle on 24 June 1999, at 15:44:00 UTC, as a part of NASA's Origins Program. FUSE detected light in the far ultraviolet portion of the electromagnetic spectrum, which is mostly unobservable by other telescopes. Its primary mission was to characterize universal deuterium in an effort to learn about the stellar processing times of deuterium left over from the Big Bang. FUSE resides in a low Earth orbit, approximately 760 km (470 mi) in altitude, with an inclination of 24.98° and a 99.80 minutes orbital period. Its Explorer program designation is Explorer 77.

The Guide Star Catalog (GSC), also known as the Hubble Space Telescope, Guide Catalog (HSTGC), is a star catalog compiled to support the Hubble Space Telescope with targeting off-axis stars. GSC-I contained approximately 20,000,000 stars with apparent magnitudes of 6 to 15. GSC-II contains 945,592,683 stars out to magnitude 21. As far as possible, binary stars and non-stellar objects have been excluded or flagged as not meeting the requirements of Fine Guidance Sensors. This is the first full sky star catalog created specifically for navigation in outer space.

<span class="mw-page-title-main">Fine guidance sensor</span> Space telescope pointing device

A fine guidance sensor (FGS) is an instrument on board a space telescope that provides high-precision pointing information as input to the telescope's attitude control systems. Interferometric FGSs have been deployed on the Hubble Space Telescope; a different technical approach is used for the James Webb Space Telescope's FGSs. In some specialized cases, such as astrometry, FGSs can also be used as scientific instruments.

<span class="mw-page-title-main">Gliese 876 b</span> Extrasolar planet orbiting Gliese 876

Gliese 876 b is an exoplanet orbiting the red dwarf Gliese 876. It completes one orbit in approximately 61 days. Discovered in June 1998, Gliese 876 b was the first planet to be discovered orbiting a red dwarf.

<span class="mw-page-title-main">Magdalena Ridge Observatory</span> American astronomical observatory

The Magdalena Ridge Observatory (MRO) is an astronomical observatory in Socorro County, New Mexico, about 32 kilometers (20 mi) west of the town of Socorro. The observatory is located in the Magdalena Mountains near the summit of South Baldy Mountain, adjacent to the Langmuir Laboratory for Atmospheric Research. Currently operational at the site is a 2.4-meter fast-tracking optical telescope, and under construction is a ten-element optical interferometer.

<span class="mw-page-title-main">Methods of detecting exoplanets</span>

Any planet is an extremely faint light source compared to its parent star. For example, a star like the Sun is about a billion times as bright as the reflected light from any of the planets orbiting it. In addition to the intrinsic difficulty of detecting such a faint light source, the light from the parent star causes a glare that washes it out. For those reasons, very few of the exoplanets reported as of January 2024 have been observed directly, with even fewer being resolved from their host star.

The Kepler Input Catalog is a publicly searchable database of roughly 13.2 million targets used for the Kepler Spectral Classification Program (SCP) and the Kepler space telescope.

<span class="mw-page-title-main">Discoveries of exoplanets</span> Detecting planets located outside the Solar System

An exoplanet is a planet located outside the Solar System. The first evidence of an exoplanet was noted as early as 1917, but was not recognized as such until 2016; no planet discovery has yet come from that evidence. What turned out to be the first detection of an exoplanet was published among a list of possible candidates in 1988, though not confirmed until 2003. The first confirmed detection came in 1992, with the discovery of terrestrial-mass planets orbiting the pulsar PSR B1257+12. The first confirmation of an exoplanet orbiting a main-sequence star was made in 1995, when a giant planet was found in a four-day orbit around the nearby star 51 Pegasi. Some exoplanets have been imaged directly by telescopes, but the vast majority have been detected through indirect methods, such as the transit method and the radial-velocity method. As of 24 July 2024, there are 7,026 confirmed exoplanets in 4,949 planetary systems, with 1007 systems having more than one planet. This is a list of the most notable discoveries.

<span class="mw-page-title-main">NASA Exoplanet Science Institute</span>

The NASA Exoplanet Science Institute (NExScI) is part of the Infrared Processing and Analysis Center (IPAC) and is on the campus of the California Institute of Technology (Caltech) in Pasadena, CA. NExScI was formerly known as the Michelson Science Center and before that as the Interferometry Science Center. It was renamed NExScI in the Fall of 2008 to reflect NASA's growing interest in the search for planets outside of the Solar System, also known as exoplanets. The executive director of NExScI is Charles A. Beichman.

<span class="mw-page-title-main">Lisa Kaltenegger</span> Austrian astronomer

Lisa Kaltenegger is an Austrian astronomer specialising in the modeling and characterization of exoplanets and the search for life. On July 1, 2014, she was appointed Associate Professor of Astronomy at Cornell University. Previously, she held a joint position at the Max Planck Institute for Astronomy in Heidelberg where she was the Emmy Noether Research Group Leader for the "Super-Earths and Life" group, and at the Center for Astrophysics | Harvard & Smithsonian in Cambridge, MA. She was appointed Lecturer in 2008 at Harvard University and 2011 at University of Heidelberg.

<i>Whipple</i> (spacecraft) Observatory for Oort Cloud objects

Whipple was a proposed space observatory in the NASA Discovery Program. The observatory would try to search for objects in the Kuiper belt and the theorized Oort cloud by conducting blind occultation observations. Although the Oort cloud was hypothesized in the 1950s, it has not yet been directly observed. The mission would attempt to detect Oort cloud objects by scanning for brief moments where the objects would block the light of background stars.

<span class="mw-page-title-main">Fine Guidance Sensor and Near Infrared Imager and Slitless Spectrograph</span> Canadian aligner and spectrometer on JWST

Fine Guidance Sensor and Near Infrared Imager and Slitless Spectrograph (FGS-NIRISS) is an instrument on the James Webb Space Telescope (JWST) that combines a Fine Guidance Sensor and a science instrument, a near-infrared imager and a spectrograph. The FGS/NIRISS was designed by the Canadian Space Agency (CSA) and built by Honeywell as part of an international project to build a large infrared space telescope with the National Aeronautics and Space Administration (NASA) and the European Space Agency (ESA). FGS-NIRISS observes light from the wavelengths of 0.8 to 5.0 microns. The instrument has four different observing modes.

References

  1. ↑ "Hubble Space Telescope Systems" (PDF). Goddard Space Flight Center, Astrophysics Science Division. p. 20. Retrieved November 27, 2023.
  2. 1 2 "Hubble's Instruments: FGS - Fine Guidance Sensors". www.spacetelescope.org. Retrieved 2017-03-03.
  3. ↑ "NASA - Refurbished Fine Guidance Sensor (FGS)". www.nasa.gov. Retrieved 2017-03-03.
  4. ↑ Fine Guidance Sensors Aboard the Hubble Space Telescope, the Scientific Capabilities of these Interferometer
  5. 1 2 3 "Fine Guidance Sensors". Space Telescope Science Institute . Retrieved November 27, 2023.
  6. 1 2 "NASA - Hubble Space Telescope Servicing Mission 4
    Fine Guidance Sensor"    . www.nasa.gov. Retrieved 2017-03-03.
  7. ↑ "Fine guidance sensors: Hubble's unsung heros". NewsTimes. Retrieved 2017-04-12.
  8. 1 2 "Fine guidance sensors: Hubble's unsung heros". NewsTimes. Retrieved 2017-03-03.
  9. 1 2 "Photo Index 1". spaceflight.nasa.gov. Archived from the original on 2009-05-26. Retrieved 2017-03-03.
  10. 1 2 Hershey, John L.; Taff, L. G. (1998-01-01). "Hubble Space Telescope Fine Guidance Sensor Astrometry of the Low-Mass Binary L722-22". The Astronomical Journal. 116 (3): 1440. Bibcode:1998AJ....116.1440H. doi: 10.1086/300516 . ISSN   1538-3881.
  11. ↑ "Hubble instruments". sci.esa.int. Retrieved 2017-03-03.
  12. 1 2 "HubbleSite - NewsCenter - Hubble Finds Smallest Kuiper Belt Object Ever Seen (12/16/2009) - the Full Story". Archived from the original on 2016-07-06. Retrieved 2017-03-21.
  13. ↑ DETECTABILITY OF OORT CLOUD OBJECTS USING KEPLER - 2009
  14. 1 2 ""Out of Whack" Planetary System Offers Clues to a Disturbing Past". UT News | The University of Texas at Austin. 2010-05-24. Archived from the original on 2016-03-10. Retrieved 2018-01-28.
  15. 1 2 3 "Hubble Space Telescope – Fine Guidance Sensors". 27 January 2017.
  16. 1 2 Tanga, P.; Hestroffer, D.; Cellino, A.; Lattanzi, M.; Martino, M. Di; Zappalà, V. (2003-04-01). "Asteroid observations with the Hubble Space Telescope FGS". Astronomy & Astrophysics. 401 (2): 733–741. Bibcode:2003A&A...401..733T. doi: 10.1051/0004-6361:20030032 . ISSN   0004-6361.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.