Since everyone has the impression that it is the Sun that revolves around the Earth, men use it to calculate the hours and measure the time that passes with clocks. This annual cycle was used by ancient civilizations, Egyptians, Mayans, Chinese or Greeks to create the first calendars. They were used mainly for agriculture, to …
You probably think like everyone else that light is immaterial, that you can not touch it or use it as you use a jet of water and use it to push objects. But Einstein taught us that it contains energy and that it can exert a force on objects. This force is called the radiation …
The advantage of radio astronomy appears when the light is stopped by the presence of clouds of dust that hide certain regions of the sky. This material allows radio-frequency radiation and longer wavelength. But depending on the spectrum studied, part of the radiation is scattered or absorbed by the material. The celestial bodies also produce …
Several large facilities are now operational in the milli and submillimetric bands. There is ALMA (Atacama Large Millimeter / submillimeter Array) installed in Chile. It is an international project (Europe, United States and Japan), each member country participating in the construction and management of its own antennas. Started in 2003 at the same time as …
Seeing big is one thing but managing priorities is more important. The era of giant telescopes does not sign the death of “small” university instruments from 0.5 to 3 m of opening. Indeed, far from being museum pieces, the “small” telescopes have the advantage of being numerous and much more available than the giants of …
The laser power of an adaptive optics is about 20 watts if not higher, 4000 times the power of a class 3A consumer laser delivering less than 5 mW! It goes without saying that a power laser can only be used when there is no plane or satellite in the sky, a glare that can …
When you see the size of small astronomical instruments sold in specialty stores, they only impress novices. On the other hand, a telescope of 200 mm in diameter measuring between 1.5 and 2 m in height like the one presented above on the left intimidates already an amateur informed by its proportions and the quality …