Stars and perspectives
“Not all stars were born at the same time; in fact, some are still being born.”
→ System of the world according to Anaximander, Oronce Fine (1494-1555).
→ Triquetum or Ptolemy's scaling, Oronce Fine (1494-1555).
→ Astrological disc illustrating the twelve signs of the zodiac, Larousse.
→ Moving sky map, French Astronomy Association.
→ Sky map, Northern and Southern Hemisphere, Original Map.
→ Sky map at a specific date and GPS position, Fourmilab, John Walker.
Constellations are networks of stars that are close enough to each other to be connected by imaginary lines, thus forming mostly symbolic figures. The most accurate term for these combinations of stars in the sky is 'asterism'.
Aster (Greek): star. Nova (Latin): explosive star. Cosmogony (Greek): in mythology, set of myths describing the birth of the universe. In astronomy, science dealing with the formation of the world and the planets. Catasterism (Greek): To rise in the sky to become a constellation.
Concave perspective: we are below the sky - the current one. Convex perspective: we are above the sky.
The internal evolution of a star results in variations in its overall luminosity and temperature.
For a long time man attributed to the stars a supernatural action on his own existence. The first discoveries stimulated the search for the original cause of the phenomena. This led to the first precise measurements of the position of the stars. The study of the sky thus became a real science over the years... Astronomy is a science of observation, it cannot act on the environment it studies, but is restricted to observing it from the outside. That explains why the progress of astronomy depends on the development of observation instruments.
Until now, stars have only been observed through their electromagnetic radiation, and more specifically through their luminous radiation. Stars differ in their brightness, which is partly due to their distance, but also in their colour. Of the approximately 5 000 stars visible to the naked eye, only a few hundred have names, and fewer than 60 are commonly used by navigators or astronomers. The final list of 88 constellations was drawn up in 1930 under the authority of the International Astronomical Union.
It takes 25,800 years for the Sun to make a complete turn and for the coincidence of the constellations and signs to be restored. The Sun therefore remains in each sign for 2,150 years. The last coincidence took place about 10,000 years ago.
France Culture, Gallica, Encyclopédie Universalis, Wikipedia.
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