Galileo Galilei (1564 – 1642) Galilao has been called the “father of modern observational astronomy.” He made improvements on the telescope that was invented by Hans Lippershey. He used the telescope to make observations of sunspots, lunar mountains and valleys, the four largest satellites of Jupiter and the phases of Venus.
He also worked on a method of determining longitudes at sea by using the positions of Jupiter’s satellites. In 1609 Galileo had built a telescope of 20 times magnification; with wich he discovered mountains and craters on the moon. He saw that the Milky Way was composed of stars. Later he made one that was 30 times magnification.
Today astronomers have telescopes that are much larger than anything used by Galileo. The $120 Million Large Binocular Telescope (LBT) sits at 10,400 ft on Mount Graham in Arizona. Its components were fabricated in several countries around the world including The United States, Italy and Germany. It was put into service in October, 2005. This telescope combines light from two mirrors to simulate a telescope with a single mirror. When it was first put into operation, astronomers operated the LBT using only one primary mirror. Later that year the second mirror became operational.
Galileo, the “father of modern observational astronomy,” did not have the materials or the technology of today’s modern LBT, but he did pave the way for modern astronomy. There are many telescopes that are similar to what Galileo used. Many are small enough to use in a back yard observatory.