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Many modern telescopes and observatories are located in space to observe astronomical objects in wavelengths of the electromagnetic spectrum that cannot penetrate the Earth's atmosphere (such as ultraviolet radiation, X-rays, and gamma rays) and are thus impossible to observe using ground-based telescopes. [1]
The GTC began its preliminary observations on 13 July 2007, using 12 segments of its primary mirror, made of Zerodur glass-ceramic by the German company Schott AG.Later, the number of segments was increased to a total of 36 hexagonal segments fully controlled by an active optics control system, working together as a reflective unit.
The Yata no Kagami represents "wisdom" or "honesty," depending on the source. [2] Its name literally means "The Eight Ata Mirror," a reference to its size. [3] [4] Mirrors in ancient Japan represented truth because they merely reflected what was shown, and were objects of mystique and reverence (being uncommon items).
Many other types of heliostat have also occasionally been used. In the very earliest heliostats, for example, which were used for daylighting in ancient Egypt, servants or slaves kept the mirrors aligned manually, without using any kind of mechanism. (There are places in Egypt where this is done today, for the benefit of tourists.
Instead of having mirrors over the sink, many Disney guests have noticed instead there’s a full-length mirror by the door so people can check their appearance on their way out.
Each mirror of the reflector is a sandwich of an aluminum honeycomb, 5 mm plate of AlMgSi alloy, covered with a thin layer of quartz to protect the mirror surface from aging. The mirrors have spherical shape with a curvature corresponding to the position of the plate in the paraboloid reflector. The reflectivity of the mirrors is around 90% ...
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There is an issue regarding the "handedness" of celestial globes. If the globe is constructed so that the stars are in the positions they actually occupy on the imaginary celestial sphere , then the star field will appear reversed on the surface of the globe (all the constellations will appear as their mirror images).