The Dunn Solar Telescope also known as the Richard B. Dunn Solar Telescope[1] is a unique vertical-axis solar telescope, in Sunspot, New Mexico located at Sacramento Peak, New Mexico. It is the main telescope at the Sunspot Solar Observatory, operated by New Mexico State University in partnership with the National Solar Observatory through funding by the National Science Foundation,[2] the state of New Mexico and private funds from other partners. The Dunn Solar Telescope specializes in high-resolution imaging and spectroscopy to help astrophysicists worldwide obtain a better understanding of how the Sun affects the Earth. Completed in 1969, it was upgraded with high-order adaptive optics in 2004 and remains a highly versatile astrophysical observatory which serves as an important test platform for developing new instrumentation and technologies. The Dunn Solar Telescope, located in Sunspot, New Mexico, is a vertical-axis solar telescope that specializes in high-resolution imaging and spectroscopy. It was completed in 1969 and received a significant upgrade with high-order adaptive optics in 2004.
Computers are mounted below the main observation room.The view from far above the observation room
The Dunn Solar Telescope specializes in solar high-resolution imaging and spectroscopy. These observations allow solar astronomers worldwide to obtain a better understanding of the Sun. The telescope was inaugurated as the world's premier high spatial resolution optical solar telescope in 1969. With a horizontal rotating 40-foot-wide observing platform, such that instruments do not have to be mounted on the telescope itself, the Dunn Solar Telescope continues to offer a versatile, user-friendly setup. It has two high-order adaptive optics benches to compensate for blurring by Earth's atmosphere. Scientists and engineers use the Dunn to investigate a range of solar activities, often in concert with satellites or rocket launches, and to develop new technologies for the 4-meter Daniel K. Inouye Solar Telescope.
Like an iceberg, only a part of the telescope's bulk is visible above ground. The optical path starts at a heliostat on top of a 136-foot-tall (41m) tower and continues 193 feet (59m) more underground to the primary mirror.[3] The lowest excavated point (the bottom of the sump) is 228 feet (69m) below ground. It then returns to one of six quartz optical windows in the floor of an optical laboratory at ground level. The whole building from top to bottom is a single instrument. The telescope's entire optical system – from the top of the Tower to the base of its underground portion, plus the 40-foot diameter observing room floor – is suspended from the top of the Tower by a mercury float bearing. The bearing, in turn, is hung on three bolts, each only 76 millimeters (3.0in) in diameter. The entire optical and mechanical structure of the telescope is longer than a football field and weighs over 250 tons. The optics are evacuated to eliminate distortion due to convection in the telescope that would otherwise be caused by the great heat produced by focusing the light of the sun. A unique feature of the telescope is its approach to image derotation: the entire 100-metre-long (330ft) telescope and 40-foot-diameter (12m) optics lab, 250 tons total, rotates suspended from a mercury float bearing at the top of the tower.
Despite the size and weight, much of the telescope can be controlled and monitored from a single control room, off to one side of the main instrument observing table.
Instruments
This section needs expansionwith: examples and additional citations. You can help by adding to it. Relevant discussion may be found on Template talk:Expand section.(July 2018)
Instruments at the DSTLight passing into instruments at DST
The Dunn Solar Telescope has a rotating optical bench, which can be configured to multiple observing setups, depending on the requirements of the science under study. The four most widely used instruments, often used together in one complex observing set up are:
Facility InfraRed Spectropolarimeter (FIRS)
The Facility IR Spectropolarimeter is a multi-slit spectropolarimeter specifically for the Dunn Solar Telescope to study magnetism on the solar surface. The instrument samples adjacent slices of the solar surface using four parallel slits to achieve high cadence, diffraction-limited, precision spectropolarimetry. Up to four spectral lines at visible and infrared wavelengths, covering four different heights in the solar atmosphere, can be observed simultaneously. It can be optimized to provide simultaneous spectral coverage at visible (3,500 – 10,000 Å) and infrared (9,000 – 24,000 Å) wavelengths through the use of a unique dual-armed design. It was designed to "capture the Fe I 6302 Å and Fe I 15648 Å or He I 10830 linesÅ with maximum efficiency ".[4]
Spectro-POlarimeter for INfrared and Optical Regions (SPINOR)
The Spectro-POlarimeter for INfrared and Optical Regions performs achromatic lens Stokes polarimetry across several visible and infrared spectral regions. Completed in 2005, it was designed to act as 'experimental oriented' instrument, built with a flexibility to allow for the combination of any many spectral lines, "limited only by practical considerations (e.g., the number of detectors available, space on the optical bench, etc.)" [5]
The Interferometric BIdimensional Spectropolarimeter (IBIS) -is a dual interferometer, imaging, spectro-polarimeter. It uses a series of precise piezo-electric tuning to rapidly scan selected spectral lines between 550 and 860nm range. This creates a time series of high-fidelity imaging, spectroscopy, and polarimetry of the Sun. It has a large circular field-of-view combined with high spectral (R ≥ 200 000), spatial ≃ 0.2″), and temporal resolution (several frames per second) [6]
Rapid Oscillations in the Solar Atmosphere (ROSA)
The Rapid Oscillations in the Solar Atmosphere (ROSA) instrument is a single-controlled system of 6 imaging fast-readout CCD cameras. The full chip on each camera can be read out 30 frames per second, and all the cameras are triggered from one control system. As such, it provides the ability to image multiple layers of the photosphere and chromosphere simultaneously. At its installation in 2010 it generated up to 12 TByte of data per day [7] making it one of the largest data sets in ground-based solar astronomy at the time.
In addition, some older instruments are available, although these are now rarely used.
Universal Birefringent Filter (UBF)
Advanced Stokes Polarimeter (ASP)
Diffraction-Limited Spectro-Polarimeter (DLSP)
Scientific discoveries, technologies, and scientists
This section needs expansionwith: examples and additional citations. You can help by adding to it. Relevant discussion may be found on Template talk:Expand section.(July 2018)
Inferring telescope polarization properties through spectral lines without linear polarization.[8] Derks, A., Beck, C., Martínez Pillet, V., 2018. Astronomy and Astrophysics volume 615, A22 (2018)
Adaptation of Dunn Solar Telescope for Jovian Doppler spectro imaging.[9] Underwood, T.A., Voelz, D., Schmider, F.-X., Jackiewicz, J., Dejonghe, J., Bresson, Y., Hull, R., Goncalves, I., Gualme, Pa., Morand, F., Preis O., SPIE Optical Engineering 10401Y (2017)
Solar coronal magnetic fields derived using seismology techniques applied to omnipresent sunspot waves.[10] Jess et al., 2016. Cover Article of Nature Physics, Volume 12 Issue 2, February 2016
Solar Multi-Conjugate Adaptive Optics at the Dunn Solar Telescope[11] Rimmele, T., Hegwer, S., Richards, K., Woeger, F.. , 2008, Multi-Conjugate Adaptive Optics.
Speckle interferometry with adaptive optics corrected solar data[12] Wöger, F., von der Lühe, O., Reardon, K., 2008, Speckle Interferometry.
History
A design for a Solar Vacuum Tower Telescope was started by the architect and engineer Charles W. Jones in 1963. Construction on the final building started in 1966 under the U.S. Army Corps of Engineers and ended in 1967, at a cost of about $3million with the architectural firm of Roghlin and Baran, Associates. Richard B. Dunn, for whom the instrument was eventually dedicated,[13] wrote an article in Sky and Telescope about the completion of the instrument in 1969. As quoted from the article "In our design we wanted most of all to eliminate problems of local seeing, which are discussed at every meeting on solar instrumentation. Solar astronomers worry about turbulence caused by the slot in the observatory dome, heating of the dome surfaces, heating of the telescope, local convection, and turbulence within the optical system...In our case, the dome was eliminated. We put a window high up on a 135-foot pyramidal tower and then evacuated the air from the entire telescope inside the tower. The latter reduces the effects of local convection and the vacuum eliminates the internal turbulence and seeing problems. Also, it provides the comfort of a heated observing room...."[14]
More than half the entire building is underground – the tower extends 136 feet above ground and 220 feet below ground. A vertical vacuum tube is enclosed within the concrete tower with 3-foot-thick walls. An entrance window at the top of the tower, and two mirrors, reflect sunlight down the vacuum tube where it is reflected off the 64 inches primary mirror. The primary mirror acts to focus the light, and sends it back up to ground level, where it exits the vacuum tube on the optical benches inside the building. The interior vacuum tube of more than 250 tons is suspended by a bearing that contains 10 tons of mercury. This bearing allowing the entire 250 ton vacuum tube to be rotated, compensating for the apparent rotation of the image as the Sun rises into the sky.
The tower telescope was originally dedicated on October 15, 1969, and renamed in 1998[15] after Richard B. Dunn.[16] A plaque at the facility reads: "Named in honor of one of solar astronomy's most creative instrument builders, this vacuum tower telescope is the masterpiece of Richard B. Dunn's long scientific career at Sacramento Peak Observatory" (1998). Construction of the vacuum tower used for the DST significantly impacted future solar instruments: So sharp were the images formed from this type of solar telescope, that almost every large solar telescope built since then has been based on the vacuum tower concept".
The Very Large Telescope (VLT) is a facility operated 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.
The Mount Wilson Observatory (MWO) is an astronomical observatory in Los Angeles County, California, United States. The MWO is located on Mount Wilson, a 1,740-meter (5,710-foot) peak in the San Gabriel Mountains near Pasadena, northeast of Los Angeles.
Observational astronomy is a division of astronomy that is concerned with recording data about the observable universe, in contrast with theoretical astronomy, which is mainly concerned with calculating the measurable implications of physical models. It is the practice and study of observing celestial objects with the use of telescopes and other astronomical instruments.
The Gemini Observatory comprises two 8.1-metre (26.6 ft) telescopes, Gemini North and Gemini South, situated in Hawaii and Chile, respectively. These twin telescopes offer extensive coverage of the northern and southern skies and rank among the most advanced optical/infrared telescopes available to astronomers. (See List of largest optical reflecting telescopes).
The Swedish 1-m Solar Telescope is a refracting solar telescope at Roque de los Muchachos Observatory, La Palma in the Canary Islands. It is run by the Institute for Solar Physics of Stockholm University. The primary element is a single fused silica lens, making it the second largest optical refracting telescope in use in the world. The 110-cm lens has a clear aperture diameter of 98 cm. The SST is most often used as a Schupmann telescope, thereby correcting the chromatic aberrations of the singlet primary.
The Nordic Optical Telescope (NOT) is an astronomical telescope located at Roque de los Muchachos Observatory, La Palma in the Canary Islands. The telescope saw first light in 1988, and was officially inaugurated during September 1989. Regular observing started in 1990. It is funded by Denmark, Sweden, Norway, Finland, and Iceland. Access is provided directly to astronomers of the funding countries, and of all nationalities through international time allocation committees.
The Canada–France–Hawaii Telescope (CFHT) is located near the summit of Mauna Kea mountain on Hawaii's Big Island at an altitude of 4,204 meters, part of the Mauna Kea Observatory. Operational since 1979, the telescope is a Prime Focus/Cassegrain configuration with a usable aperture diameter of 3.58 metres (11.7 ft).
The NASA Infrared Telescope Facility is a 3-meter (9.8 ft) telescope optimized for use in infrared astronomy and located at the Mauna Kea Observatory in Hawaii. It was first built to support the Voyager missions and is now the US national facility for infrared astronomy, providing continued support to planetary, solar neighborhood, and deep space applications. The IRTF is operated by the University of Hawaii under a cooperative agreement with NASA. According to the IRTF's time allocation rules, at least 50% of the observing time is devoted to planetary science.
Big Bear Solar Observatory (BBSO) is a university-based solar observatory in the United States. It is operated by New Jersey Institute of Technology (NJIT). BBSO has a 1.6-meter (5.2 ft) clear aperture Goode Solar Telescope (GST), which has no obscuration in the optical train. BBSO is located on the north side of Big Bear Lake in the San Bernardino Mountains of southwestern San Bernardino County, California, U.S., approximately 120 kilometers (75 mi) east of downtown Los Angeles. The telescopes and instruments at the observatory are designed and employed specifically for studying the activities and phenomena of the Sun.
A vector magnetograph is a type of imaging telescope that can estimate the 3-D vector of the magnetic field on a distant body with a resolved line spectrum. Magnetographs are useful for studying the Sun because the surface magnetic field is important to the creation and maintenance of the solar corona, and gives rise to the phenomena of solar flares and space weather.
The Daniel K. Inouye Solar Telescope (DKIST) is a scientific facility for studies of the sun at Haleakala Observatory on the Hawaiian island of Maui. Known as the Advanced Technology Solar Telescope (ATST) until 2013, it was named after Daniel K. Inouye, a US Senator for Hawaii. It is the world's largest solar telescope, with a 4-meter aperture. The DKIST is funded by National Science Foundation and managed by the National Solar Observatory. The total project cost is $344.13 million. It is a collaboration of numerous research institutions. Some test images were released in January 2020. The end of construction and transition into scientific observations was announced in November 2021.
The Vacuum Tower Telescope is an evacuated-optics solar telescope located at the Teide Observatory on Tenerife in the Canary Islands. It is operated by the Kiepenheuer-Institut für Sonnenphysik (KIS).
The Mount Abu InfraRed Observatory (MIRO) is located near the town Mount Abu in the state of Rajasthan, India. The observatory is at an altitude of 1680 metres and is adjacent to Guru Shikhar, highest peak of the Aravalli Range. The 1.2 m infrared telescope at It is the first major facility in India specifically designed for ground-based, infrared observations of celestial objects. Further the low amount of precipitable water vapour at Guru Shikhar makes it a good site for the infrared telescope observations. The site has been found to be good for astronomical observations.
Integral field spectrographs (IFS) combine spectrographic and imaging capabilities in the optical or infrared wavelength domains (0.32 μm – 24 μm) to get from a single exposure spatially resolved spectra in a bi-dimensional region. The name originates from the fact that the mesurements result from integrating the light on multiple sub-regions of the field. Developed at first for the study of astronomical objects, this technique is now also used in many other fields, such bio-medical science and Earth remote sensing. Integral field spectrography is part of the broader category of snapshot hyperspectral imaging techniques, itself a part of hyperspectral imaging.
ZIMPOL/CHEOPS is a polarimetric imager being developed for the Very Large Telescope for the direct detection of extra-solar planets. The imager is operated by the European Southern Observatory on Cerro Paranal in the Atacama Desert of northern Chile.
Philip R. Goode is an American theoretical physicist also working in observational astronomy and its instrumentation. He is a Distinguished Research Professor of Physics at New Jersey Institute of Technology (NJIT) with an H-index > 60. His career divides into five overlapping periods as follows:
Spectro-Polarimetric High-contrast Exoplanet REsearch (VLT-SPHERE) is an adaptive optics system and coronagraphic facility at the Very Large Telescope (VLT). It provides direct imaging as well as spectroscopic and polarimetric characterization of exoplanet systems. The instrument operates in the visible and near infrared, achieving, albeit over a limited field of view, superior image quality and contrast for bright targets.
Richard Brandner Dunn was an American solar physicist and astronomer who was a pioneer in solar physics. He is known for his designs of solar telescopes and their instruments, most notably the Richard B. Dunn Solar Telescope. At the time of his death he was astronomer emeritus of the National Solar Observatory.
References
↑ Raftery, Claire (2018-04-30). "Dunn Solar Telescope". NSO - National Solar Observatory. Retrieved 2023-09-12.{{cite web}}: CS1 maint: url-status (link)
↑ Reardon, K. P.; Cavallini, F. (2008-02-14), "Characterization of Fabry-Perot interferometers and multi-etalon transmission profiles - the IBIS instrumental profile", Astronomy and Astrophysics, 481 (3): 897–912, Bibcode:2008A&A...481..897R, doi:10.1051/0004-6361:20078473
↑ Jess, David B.; Reznikova, Veronika E.; Ryans, Robert S. I.; Christian, Damian J.; Keys, Peter H.; Mathioudakis, Mihalis; MacKay, Duncan H.; Krishna Prasad, S.; Banerjee, Dipankar; Grant, Samuel D. T.; Yau, Sean; Diamond, Conor (2016), "Solar coronal magnetic fields derived using seismology techniques applied to omnipresent sunspot waves", Nature Physics, 12 (2): 179–185, arXiv:1605.06112, Bibcode:2016NatPh..12..179J, doi:10.1038/nphys3544, S2CID118433180
↑ Rimmele, T.; Hegwer, S.; Richards, K.; Woeger, F. (2008), "Solar Multi-Conjugate Adaptive Optics at the Dunn Solar Telescope", Advanced Maui Optical and Space Surveillance Technologies Conference: E18, Bibcode:2008amos.confE..18R
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.
Related media on Commons 
