Dutch Open Telescope

The Dutch Open Telescope short DOT is an optical solar telescope with a 45 cm primary mirror and is part of the Roque de los Muchachos Observatory on La Palma in the vicinity of the Swedish 1- m Solar Telescope.

Thus it reaches an angular resolution of 0.2 arc seconds for a prolonged periods of time. For further optimization of images, while the so-called DOT despeckling mechanism will be used. One of his successes was the images of the transit of Venus in 2004, which can be viewed on this website DOT.

History

Before it became part of the European Northern Observatory, it was owned by the Institute of Astronomy and the Department of Physics and Astronomy at the University of Utrecht and still others.

Cameras

The DOT has six cameras, each with a different optical filters. All these filters may be used in parallel at the same time, which allows simultaneous observation at different wavelengths and thus, the results are comparable to the best. In addition, some of the filters are also adjustable so that observations at different points of the spectral lines are possible.

Open structure

The DOT is an open telescope, which means tower, mount and telescope are open and unprotected during the observation, the wind blow through the telescope. Thus, a relatively constant temperature at the levels are reached, which the seeing significantly reduced. Conventional telescope designs with solar telescopes often have the problem that warm air from the floor, which was heated by the sun rises along the tower and mirror what the resulting picture quality hurts.

A drawback of this design is that the support structure must be extremely rigid, so it does not move in the wind. Normally, this function takes a solid tower or the telescope is actually located within a tower or dome. The optics of the telescope of the DOT is located two meters in front of the primary mirror and to prevent blur when imaging, the cameras are mounted very rigid and can be precisely adjusted precisely to the micrometer.

Roof construction

Another novel feature of the DOT 's roof structure, which has been prepared from a particular polymer fiber. It keeps the mold when it is stretched and is also after a long time without fatigue. Each of the individual saddle-shaped roof parts is in tension when the roof is closed, thereby making it more stable.

Lichtgranulation

The despeckling algorithm allows up to the diffraction- related limits of the telescope resolve objects themselves and the more often to achieve optimal image quality than is typically limited by the seeing would be the case. During the operation, 100 images are taken with extremely short exposure time of the same object (eg, a granular structure of the Sun), always in the atmosphere have properties at a time interval changed significantly but not the properties of the observed object. Then the image is improved by means of statistics and a whole lot of computing power ( a 35 Dual Core Xeon computer cluster calculates the despeckling algorithm). Before the summer of 2005, this calculation needed for months, the new computer network reduces the computation time to the length of one night.

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