| Dutch Open Telescope | |
The Dutch Open Telescope with the canopy closed.
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| Organization | SIU, Dept. of Physics and Astronomy, Universiteit Utrecht, and others |
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| Location | Roque de los Muchachos Observatory, La Palma |
| Coordinates | |
| Altitude | 2350 m |
| Wavelength | Optical |
| Built | 1997 |
| Telescope style | Reflecting telescope |
| Diameter | 0. Utrecht University ( Universiteit Utrecht in Dutch) is a University in Utrecht, The Netherlands. Roqué de los Muchachos Observatory is an Astronomical observatory located in the municipality of Garafía on the island of La Palma in the Canary Isla de La Palma (known in English as "La Palma" not to be confused with "Palma" in the Balearic Islands is a Spanish volcanic ocean island In Physics wavelength is the distance between repeating units of a propagating Wave of a given Frequency. 45 m |
| Angular resolution | 0. Angular resolution describes the resolving power of any image forming device such as an optical or Radio telescope, a Microscope, a Camera 071 arcsec/pixel |
| Collecting area | 0. 15 m² |
| Focal length | 2. The focal length of an optical system is a measure of how strongly it converges (focuses or diverges (diffuses Light. 0 m |
| Mounting | Open steel framework |
| Dome | Fold-away clam-like shell |
| Website | http://dot.astro.uu.nl/ |
The Dutch Open Telescope (DOT), located on Roque de los Muchachos Observatory, La Palma (near the Swedish Solar Telescope), is an optical solar telescope with a main mirror of 45 centimeter and can reach an 0. A telescope mount is a mechanical structure which supports a Telescope. Roqué de los Muchachos Observatory is an Astronomical observatory located in the municipality of Garafía on the island of La Palma in the Canary Isla de La Palma (known in English as "La Palma" not to be confused with "Palma" in the Balearic Islands is a Spanish volcanic ocean island The Swedish Solar Telescope (or SST is a 1 m telescope at Roque de los Muchachos Observatory, La Palma in the Canary Islands. A telescope is an instrument designed for the observation of remote objects and the collection of Electromagnetic radiation. 2 arcsec resolution for sustained periods. A minute of arc, arcminute, or MOA is a unit of angular measurement, equal to one sixtieth (1/60 of one degree. For further optimization of the images, the DOT uses the image despeckle mechanism. One of the successes was the recording of the 2004 Venus transit, the movies recorded can be seen at the DOT website. A transit of Venus across the Sun takes place when the Planet Venus passes directly between the Sun and Earth, obscuring a small portion of the
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Cameras
The DOT has 6 cameras, each with a different filter, described at the DOT website. 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. A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from an excess or deficiency of photons in a narrow frequency range compared
Open structure
The DOT is an open telescope, which means that the structure is physically open, and the wind can blow through. The William Herschel Telescope or WHT was first conceived in the late 1960s when the Anglo-Australian Observatory was being designed Because the wind blows along the mirror the air has a more or less constant temperature, and this prevents seeing. Astronomical seeing refers to the blurring and twinkling of astronomical objects such as stars caused by Turbulence in the Earth's atmosphere 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 to move in the wind. Normally a solid tower takes care of this (as is done with the Swedish Solar Telescope (SST), for example), or the telescope is placed inside a dome. The Swedish Solar Telescope (or SST is a 1 m telescope at Roque de los Muchachos Observatory, La Palma in the Canary Islands. 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.
Custom designed roof
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).
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. Granules on the Photosphere of the Sun are caused by Convection currents ( Thermal columns Bénard cells) of plasma within Then by using statistics and a lot of computing (a 35 dual-Xeon computer-cluster powers these despeckle algorithms) the image is improved. The Xeon brand refers to many families of Intel 's x86 Multiprocessing CPUs – for dual-processor (DP and multi-processor (MP configuration Before the summer of 2005 the computation took months after a day of observations, but the new cluster reduces this time to a night.
External links
- Dutch Open Telescope (DOT) on the internet
- DOT Database, a compilation of DOT-images
- IAC website, the research institute which operates the observatory
- Paper on the [1] despeckle algorithm
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