Cassiopeéa

Caelum /ˈsiːləm/ is a faint constellation in the southern sky, introduced in the 1750s by Nicolas Louis de Lacaille and counted among the 88 modern constellations. Its name means “chisel” in Latin, and it was formerly known as Caelum Scalptorium (“the engravers’ chisel”); It is a rare word, unrelated to the far more common Latin caelum, meaning “sky, heaven, atmosphere”. It is the eighth-smallest constellation, and subtends a solid angle of around 0.038 steradians, just less than that of Corona Australis.

A caldera is a large cauldron-like depression that forms following the evacuation of a magma chamber/reservoir. When large volumes of magma are erupted over a short time, structural support for the crust above the magma chamber is lost. The ground surface then collapses downward into the partially emptied magma chamber, leaving a massive depression at the surface (from one to dozens of kilometers in diameter)