Primary mirror
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A primary mirror (or primary) is the principal light-gathering surface (the objective) of a reflecting telescope.
Description
The primary mirror of a reflecting telescope is a
Solid primary mirrors have to sustain their own weight and not deform under gravity, which limits the maximum size for a single piece primary mirror.
Segmented mirror configurations are used to get around the size limitation on single primary mirrors. For example, the Giant Magellan Telescope will have seven 8.4 meter primary mirrors, with the resolving power equivalent to a 24.5 m (80.4 ft) optical aperture.[2]
Superlative primary mirrors
The largest optical telescope in the world as of 2009 to use a non-segmented single-mirror as its primary mirror is the 8.2 m (27 ft)
Radio and submillimeter telescopes use much larger dishes or antennae, which do not have to be made as precisely as the mirrors used in optical telescopes. The Arecibo Telescope used a 305 m dish, which was the world largest single-dish radio telescope fixed to the ground.[5][6] The Green Bank Telescope has the world's largest steerable single radio dish with 100 m in diameter.[7] There are larger radio arrays, composed of multiple dishes which have better image resolution but less sensitivity.[8]
See also
- Active optics
- Honeycomb mirror
- Liquid-mirror telescope
- List of largest optical reflecting telescopes
- List of telescope parts and construction
- Mirror mount
- Mirror support cell
- Secondary mirror
- Silvering
References
- ^ "Mirror, Primary Backup, Hubble Space Telescope". Smithsonian - National Air and Space Museum. 2007-08-28. Archived from the original on 2007-10-13. Retrieved 2008-04-26.
- ^ Maggie McKee (2007-10-04). "Giant telescope in race to become world's largest". New Scientist. Retrieved 2009-03-27.
- ^ "Hi-tech - The Subaru Telescope". Kids Web Japan. 2007-05-21. Archived from the original on 2023-04-10. Retrieved 2024-01-22.
- ^ "Giant telescope opens both eyes". BBC News. 2008-03-06. Archived from the original on 2023-07-10. Retrieved 2008-03-06.
- ^ "The 305 meter radio telescope". National Astronomy and Ionosphere Center - Arecibo Observatory. 2004-12-01. Archived from the original on 2015-02-04. Retrieved 2015-01-22.
- ^ "Giant Arecibo radio telescope collapses in Puerto Rico". The Guardian. Associated Press. 2020-12-01. Archived from the original on 2023-03-25. Retrieved 2020-12-01.
- ^ "Green Bank". National Radio Astronomy Observatory. 2011-05-20. Archived from the original on 2023-08-13. Retrieved 2015-01-22.
- ^ "Radio Telescope". University of Oregon. 2005-02-22. Archived from the original on 2022-10-06. Retrieved 2015-01-22.