Newtonian telescope Newtonian telescope The Newtonian telescope, also called the Newtonian reflector or just the Newtonian, is a type of reflecting telescope invented by the English scientist Sir Isaac Newton (1642–1727), using a concave primary mirror and a flat diagonal secondary mirror. Newton's first reflecting telescope was completed in 1668 and is the earliest known functional reflecting telescope. The Newtonian telescope's simple design makes it very popular with amateur telescope makers. Newton's idea for a reflecting telescope was not new. Galileo Galilei and Giovanni Francesco Sagredo had discussed using a mirror as the image forming objective soon after the invention of the
Galilean cannon now comes with safety goggles. It is possible to demonstrate the principle more simply with just two balls, such as a basketball and a tennis ball. If an experimenter balances the tennis ball on top of the basketball and drops the pair to the ground, the tennis ball will rebound to many times the height from which it was released. The Guinness world record for the tallest Galilean cannon drop ever was set by Dr. Brian Greene on the May 25, 2016 episode of "The Late Show with Stephen Colbert". Galilean cannon A Galilean cannon is a device that demonstrates