It has been known since the discovery of Heinrich Hertz in 1887 that radio waves are of the same nature as light waves. In particular they propagate in a vacuum …
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While the eye is sensitive only to the light perceived instantly, the silver medium (photo plate and films) that was still used until the 1980s can record the light received …
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It is enough to have spent a few seconds on the eyepiece of a so-called azimuthal instrument, mounted on a tripod, to be aware of the sidereal movement which causes …
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Around the world, about thirty observatories have dedicated at least one telescope to the study of the Sun. Given the atmospheric turbulence, it is almost impossible to use instruments over …
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Since the manufacture of the 5 m diameter mirror of the Mount Palomar Observatory in 1939, because of their gross mass exceeding 40 tons, the mirrors of the large telescopes …
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At the turn of the twentieth century, Lorentz understood the futility of mechanical support to explain the propagation of the electromagnetic field. He also discovered the theory of electrons. Meanwhile, …