page_title: Dutch Open Telescope
section_title: Custom designed roof
hierarchical_section_title: Dutch Open Telescope / Custom designed roof
caption_attribution_description: English: Made and released under GFDL by Tim van Werkhoven. This is an image of the 45 cm mirror of the Dutch Open Telescope.
context_page_description: The Dutch Open Telescope is an optical solar telescope located on Roque de los Muchachos Observatory, La Palma. 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 the 2004 Venus transit.
  The open design was a departure from vacuum-style solar telescopes, and helped pave the way for bigger solar telescopes.
context_section_description: 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.
caption: Close-up of the DOT mirror
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