Galileo Galilei is credited with building the first functional telescope in 1609.

Galileo primarily used his telescope to observe the planets, making groundbreaking discoveries such as the four largest moons of Jupiter.

Galileo discovered Jupiter and its four largest moons using his telescope.

Galileo observed mountains and valleys on the surface of the moon using his telescope.

Christiaan Huygens discovered the rings of Saturn in 1655.

The Gran Telescopio Canarias, located on the Canary Islands, is the largest telescope ever built.

The Hubble Space Telescope is a reflecting telescope.

The primary mirror diameter of the Hubble Space Telescope is 2.4 meters.

The Hubble Space Telescope's main mission is to observe galaxies and study the universe's expansion.

The Hubble Space Telescope was the first space telescope launched by NASA.

The James Webb Space Telescope is the successor to the Hubble Space Telescope.

The primary mirror diameter of the James Webb Space Telescope is 6.5 meters.

The James Webb Space Telescope's main mission is to observe galaxies and study the universe's expansion.

The James Webb Space Telescope was launched in 2021.

The expected lifespan of the James Webb Space Telescope is 10 years.