PALOMAR OBSERVATORY

The observatory is one of the most emblematic scientific facilities in the world. Designed nearly a century ago, its activities began in the 1930s and continue to this day. Its reputation is primarily the result of the vision and perseverance of the great astronomer George Ellery Hale (1868-1938), a graduate of the prestigious Massachusetts Institute of Technology (MIT) and a key member in the development of the famous California Institute of Technology (Caltech). He was also responsible for the construction of the large telescope of the Yerkes Observatory in 1897 and the one on Mount Wilson in 1908.

Despite the economic recession, he managed to obtain a grant of 6 million dollars from the Rockefeller Foundation in 1928 to build a giant telescope: 5.08 m in diameter, the largest ever built at that time. Fired up by the disappointing quality of the mirror of the Hooker telescope that he had previously supervised in the Mount Wilson Observatory, the astronomer focused his research on the glass to be used to obtain a much higher optical quality. Thus, the mirror of 5 m will be manufactured from a new material, Pyrex, able to support the constraints related to the weight of glass and the amplitudes of temperatures on the site.

On March 25, 1936, the disk was loaded onto a specially prepared railroad car for transport to Caltech in Pasadena. Imagine the thousands of people who flocked across the country to see the "Big Eye" along the way! On April 10 of the same year, the mirror arrived at its destination: the fastidious work of polishing began, essential to give it its final optical form. 13 years will be necessary. On June 3, 1948, 10 years after the death of its initiator, the telescope will be officially inaugurated in front of 1 000 guests. A few months later, the first image made with the device was exposed by the famous astronomer Edwin Hubble.

For decades, the work carried out at the observatory mainly concerned the structure of the Universe, the evolution of stars and the constitution of matter. The Hale telescope remained the largest in the world until 1975, when it was supplanted by the 6-meter telescope of the Zelentchoukskaïa Observatory, located in the Caucasus, in the Soviet Union - in the middle of the Cold War.

Let's get back to the visit: today, the Hale telescope is located at an altitude of 1,710 meters, in a beautiful mountainous region between San Diego and Los Angeles... Which is unfortunately not ideal in terms of light pollution - hence the construction of new American observatories in other states and countries, like Hawaii and Chile, among others. Nevertheless, Palomar Observatory remains very active under the leadership of its manager, the California Institute of Technology. For example, some of the instruments are constantly scanning the sky for the famous near-Earth asteroids that could - one day - hit the Earth.

The wooded environment makes the visit particularly pleasant, especially since the domes are accessible via well-designed galleries. Also on the program: a museum area and a souvenir store. Nevertheless, be careful; the site being very isolated, it is advisable to bring a picnic, unless you stop in one of the few restaurants located on the road.