Radioastronomy

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 in a straight line (geodesic) at a constant speed of 299792.45 km / s. It is by their wavelength (or their frequency) that the hertzian …

Photography and its Limits

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 during a long exposure. A camera equipped with an ordinary emulsion can detect very weak objects that the eye as exercised will never see, even …

The Equatorial Mount

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 the whole celestial vault in the opposite direction to the rotation of the Earth, causing all the stars from east to west. With manual retraction …

Solar Telescope

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 one meter in diameter unless you have a high altitude site or install adaptive optics. Also for the time being, the largest solar telescope is …

Modern Times

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, the mathematicians Gauss, Lobatchevski, Bolyai and Riemann created the concept of curved space and endeavored to define the peculiarities of coordinate systems relative to each …