Dutch Open Telescope

Last updated
Dutch Open Telescope
Dutch Open Telescope dome closed.jpg
The Dutch Open Telescope with the canopy closed.
Part of Roque de los Muchachos Observatory   OOjs UI icon edit-ltr-progressive.svg
Location(s) La Palma, Atlantic Ocean, international waters
Coordinates 28°45′35″N17°52′53″W / 28.759642°N 17.881322°W / 28.759642; -17.881322 OOjs UI icon edit-ltr-progressive.svg
Altitude2,350 m (7,710 ft) OOjs UI icon edit-ltr-progressive.svg
Telescope style optical telescope
reflecting telescope
solar telescope   OOjs UI icon edit-ltr-progressive.svg
Diameter0.45 m (1 ft 6 in) OOjs UI icon edit-ltr-progressive.svg
Angular resolution 0.2 arcsecond  OOjs UI icon edit-ltr-progressive.svg
Collecting area0.15 m2 (1.6 sq ft) OOjs UI icon edit-ltr-progressive.svg
Focal length 2 m (6 ft 7 in) OOjs UI icon edit-ltr-progressive.svg
Mounting equatorial mount   OOjs UI icon edit-ltr-progressive.svg
Enclosure canopy   OOjs UI icon edit-ltr-progressive.svg
Website www.dot.iac.es OOjs UI icon edit-ltr-progressive.svg
Canarias-loc.svg
Red pog.svg
Location of Dutch Open Telescope
  Commons-logo.svg Related media on Commons

The Dutch Open Telescope (DOT) is an optical solar telescope located on Roque de los Muchachos Observatory, La Palma (near the Swedish 1-m Solar Telescope). With a main mirror of 45 centimeters, it can reach an 0.2 arcsec resolution for sustained periods. For further optimization of the images, the DOT uses the image despeckle mechanism. It was used to record movies of the 2004 Venus transit. [1]

Contents

The open design was a departure from vacuum-style solar telescopes, and helped pave the way for bigger solar telescopes. [2]

Main mirror of the DOT DOT main mirror.jpg
Main mirror of the DOT

Cameras

The DOT has 6 cameras, each with a different filter. [3] These filters can be used at the same time, and allows images to be taken at different wavelengths to be compared. Furthermore, some filters are tunable, allowing observers to take images at several points in the spectral lines.

Open structure

William Herschel Telescope and the DOT WHT DOT LaPalma.jpg
William Herschel Telescope and the DOT

The DOT is an open telescope, which means that the structure is physically open, and the wind can blow through. Because the wind blows along the mirror the air has a more or less constant temperature, and this prevents seeing. Conventional telescope designs have the problem that hot air from the ground (which is hotter due to solar heating) is blown up along the tower, and this causes air with different temperatures to blow along the telescope, which degrades the image. A drawback of this open structure is that the skeleton has to be very rigid (do not confuse with strong), to prevent the structure from moving in the wind. Normally a solid tower takes care of this (as is done with the Swedish 1-m Solar Telescope (SST), for example), or the telescope is placed inside a dome. The DOT does not have this and thus has to be very rigid. The optical part of the telescope is mounted 2 meters in front of the main mirror, and to prevent blurred images, the cameras are mounted very rigidly and can move with a precision of micrometres.

The telescope mirror can be upgraded in size to 3/4 of a meter with small modification, and even larger with additional adaptions. [2]

Custom designed roof

Close-up of the DOT mirror Dutch Open Telescope Mirror.jpg
Close-up of the DOT mirror

Another novel feature of the DOT is the roof which is made of a special polymer fibre which retains its shape after being stretched and does not loosen after time. The shape of the several roof sections are made in such a way that they are always under tension when closed, so it is stronger (i.e., the sections are saddle-shaped). Patterning and test installation of this specific skin is done in cooperation with the team of Poly-Ned who made more retractable coverings for telescope structures. Example of other similar projects is: GREGOR project on Tenerife. A high UV resistance PVC coated Polyester weave is important for this kind of structures. We call them Textielarchitecture from the Dutch ground.

Despeckle

The despeckle algorithm that improves the image quality allows observers to reach the diffraction limit of the telescope more often than the seeing would normally allow. The despeckle takes 100 images of the same object (e.g., a granule), but each with a temporal distance such that the atmosphere has changed drastically, but the object has not. Then by using statistics and high powered computing (a 35 dual-Xeon computer-cluster powers these despeckle algorithms) the image is improved. Before the summer of 2005 the computation took months after a day of observations, but the new cluster reduces this time to a night.

See also

Related Research Articles

<span class="mw-page-title-main">Astrophotography</span> Imaging of astronomical objects

Astrophotography, also known as astronomical imaging, is the photography or imaging of astronomical objects, celestial events, or areas of the night sky. The first photograph of an astronomical object was taken in 1840, but it was not until the late 19th century that advances in technology allowed for detailed stellar photography. Besides being able to record the details of extended objects such as the Moon, Sun, and planets, modern astrophotography has the ability to image objects outside of the visible spectrum of the human eye such as dim stars, nebulae, and galaxies. This is accomplished through long time exposure as both film and digital cameras can accumulate and sum photons over long periods of time or using specialized optical filters which limit the photons to a certain wavelength.

<span class="mw-page-title-main">W. M. Keck Observatory</span> Astronomical observatory in Hawaii

The W. M. Keck Observatory is an astronomical observatory with two telescopes at an elevation of 4,145 meters (13,600 ft) near the summit of Mauna Kea in the U.S. state of Hawaii. Both telescopes have 10 m (33 ft) aperture primary mirrors, and, when completed in 1993 and 1996, they were the largest optical reflecting telescopes in the world. They are currently the third and fourth largest.

<span class="mw-page-title-main">Adaptive optics</span> Technique used in optical systems

Adaptive optics (AO) is a technique of precisely deforming a mirror in order to compensate for light distortion. It is used in astronomical telescopes and laser communication systems to remove the effects of atmospheric distortion, in microscopy, optical fabrication and in retinal imaging systems to reduce optical aberrations. Adaptive optics works by measuring the distortions in a wavefront and compensating for them with a device that corrects those errors such as a deformable mirror or a liquid crystal array.

<span class="mw-page-title-main">Swedish Solar Telescope</span> Telescope on La Plama, Canary Islands

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 largest optical refracting telescope in use in the world. The Swedish 1-m Solar Telescope, with a lens diameter of 43 inches, is technically larger than Yerkes Observatory, only 39 inches are clear for the aperture. The SST is most often used as a Schupmann telescope, thereby correcting the chromatic aberrations of the singlet primary.

<span class="mw-page-title-main">Galileo National Telescope</span>

The Galileo National Telescope, is a 3.58-meter Italian telescope, located at the Roque de los Muchachos Observatory on the island of La Palma in the Canary Islands, Spain. The TNG is operated by the "Fundación Galileo Galilei, Fundación Canaria", a non-profit institution, on behalf of the Italian National Institute of Astrophysics (INAF). The telescope saw first light in 1998 and is named after the Italian Renaissance astronomer Galileo Galilei.

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

Transition Region and Coronal Explorer was a NASA heliophysics and solar observatory designed to investigate the connections between fine-scale magnetic fields and the associated plasma structures on the Sun by providing high resolution images and observation of the solar photosphere, the transition region, and the solar corona. A main focus of the TRACE instrument is the fine structure of coronal loops low in the solar atmosphere. TRACE is the third spacecraft in the Small Explorer program, launched on 2 April 1998, and obtained its last science image on 21 June 2010, at 23:56 UTC.

<span class="mw-page-title-main">Roque de los Muchachos Observatory</span> Observatory

Roque de los Muchachos Observatory is an astronomical observatory located in the municipality of Garafía on the island of La Palma in the Canary Islands, Spain. The observatory site is operated by the Instituto de Astrofísica de Canarias, based on nearby Tenerife. ORM is part of the European Northern Observatory.

<span class="mw-page-title-main">NASA Infrared Telescope Facility</span>

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.

<span class="mw-page-title-main">Solar Orbiter</span> European space-based solar observatory

The Solar Orbiter (SolO) is a Sun-observing probe developed by the European Space Agency (ESA) with a National Aeronautics and Space Administration (NASA) contribution. Solar Orbiter, designed to obtain detailed measurements of the inner heliosphere and the nascent solar wind, will also perform close observations of the polar regions of the Sun which is difficult to do from Earth. These observations are important in investigating how the Sun creates and controls its heliosphere.

<span class="mw-page-title-main">Extremely Large Telescope</span> Major astronomical facility in Chile

The Extremely Large Telescope (ELT) is an astronomical observatory under construction. When completed, it will be the world's largest optical/near-infrared extremely large telescope. Part of the European Southern Observatory (ESO) agency, it is located on top of Cerro Armazones in the Atacama Desert of northern Chile.

<span class="mw-page-title-main">Richard B. Dunn Solar Telescope</span> Optical telescope dedicated to observing the Sun

The Dunn Solar Telescope also known as the Richard B. Dunn Solar Telescope 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, 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 that 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.

<span class="mw-page-title-main">Solar telescope</span> Telescope used to observe the Sun

A solar telescope or a solar observatory is a special-purpose telescope used to observe the Sun. Solar telescopes usually detect light with wavelengths in, or not far outside, the visible spectrum. Obsolete names for Sun telescopes include heliograph and photoheliograph.

<span class="mw-page-title-main">Vera C. Rubin Observatory</span> 8 meter astronomical survey telescope

The Vera C. Rubin Observatory, formerly known as the Large Synoptic Survey Telescope (LSST), is an astronomical observatory currently under construction in Chile. Its main task will be carrying out a synoptic astronomical survey, the Legacy Survey of Space and Time. The word synoptic is derived from the Greek words σύν and ὄψις, and describes observations that give a broad view of a subject at a particular time. The observatory is located on the El Peñón peak of Cerro Pachón, a 2,682-meter-high mountain in Coquimbo Region, in northern Chile, alongside the existing Gemini South and Southern Astrophysical Research Telescopes. The LSST Base Facility is located about 100 kilometres (62 mi) away from the observatory by road, in the town of La Serena. The observatory is named for Vera Rubin, an American astronomer who pioneered discoveries about galaxy rotation rates.

<span class="mw-page-title-main">Daniel K. Inouye Solar Telescope</span> Scientific facility at Haleakala Observatory in Hawaii, US

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 InterPlanetary Network (IPN) is a group of spacecraft equipped with gamma ray burst (GRB) detectors. By timing the arrival of a burst at several spacecraft, its precise location can be found. The precision for determining the direction of a GRB in the sky is improved by increasing the spacing of the detectors, and also by more accurate timing of the reception. Typical spacecraft baselines of about one AU and time resolutions of tens of milliseconds can determine a burst location within several arcminutes, allowing follow-up observations with other telescopes.

<span class="mw-page-title-main">Vacuum Tower Telescope</span> Solar telescope on Tenerife operated by KIS

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 Sunrise balloon-borne solar observatory consists of a 1m aperture Gregory telescope, a UV filter imager, an imaging vector polarimeter, an image stabilization system and further infrastructure. The first science flight of Sunrise yielded high-quality data that reveal the structure, dynamics and evolution of solar convection, oscillations and magnetic fields at a resolution of around 100 km in the quiet Sun.

<span class="mw-page-title-main">Astronomical filter</span> Telescope accessory used to improve details of viewed objects

An astronomical filter is a telescope accessory consisting of an optical filter used by amateur astronomers to simply improve the details and contrast of celestial objects, either for viewing or for photography. Research astronomers, on the other hand, use various band-pass filters for photometry on telescopes, in order to obtain measurements which reveal objects' astrophysical properties, such as stellar classification and placement of a celestial body on its Wien curve.

<span class="mw-page-title-main">Goode Solar Telescope</span> Scientific facility in Big Bear Lake, California, U.S.

The Goode Solar Telescope (GST) is a scientific facility for studies of the Sun named after Philip R. Goode. It was the solar telescope with the world's largest aperture in operation for more than a decade. Located in Big Bear Lake; California, the Goode Solar Telescope is the main telescope of the Big Bear Solar Observatory operated by the New Jersey Institute of Technology (NJIT). Initially named New Solar Telescope (NST), first engineering light was obtained in December 2008, and scientific observations of the Sun began in January 2009. On July 17, 2017, the NST was renamed in honor of Goode, a former, and founding director of NJIT's Center for Solar-Terrestrial Research and the principal investigator of the facility. Goode conceived, raised the funds, and assembled the team that built and commissioned the telescope, and it was the highest resolution solar telescope in the world (until the end of 2019) and the first facility class solar telescope built in the U.S. in a generation.

<span class="mw-page-title-main">ExoLife Finder</span> Proposed telescope

The ExoLife Finder (ELF) telescope is an under-development hybrid interferometric telescope being designed at the Instituto de Astrofisica de Canarias (IAC) for the direct detection and imaging of exoplanets and potentially water-bearing exoplanets. Developed by a collaboration of scientists and engineers including the PLANETS Foundation, the ELF aims to analyze the surfaces and atmospheres of exoplanets for evidence of life, focusing on nearby star systems within 25 light years of Earth. The telescope’s design features non-redundant circular arrays of 5-meter-scale mirrors and tensegrity-based mechanical support with an outer diameter of 35m. It uses multiple layers of advanced atmospheric wavefront sensing and control. It is a scalable optical concept, and could be built within a 10 year timeframe. A 3.5-meter precursor called the Small ELF (SELF) is currently being built in the Canary Islands. The ELF's first targets will include nearby stars cooler than the Sun.

References

  1. R.J. Rutte. "DOT and the 2004 Venus transit". robrutten.nl. Retrieved 9 June 2024.
  2. 1 2 R.J. Rutte; R.H. Hammerschlag; F.C.M. Betonville (1999). "The Dutch Open Telescope 1999ASPC..158...57R Page 57". adsabs.harvard.edu. Retrieved 9 June 2024.
  3. Rutte, Rob. "DOT tomography". robrutten.nl. Retrieved 9 June 2024.