Telescopes are such optical instruments which make distant objects appear to be magnified . Actually telescopes have arranged lenses and spherical mirrors which enable us to see distant objects easily.
The first telescope invented was a refracting telescope invented somewhere in Netherlands at the beginning of the 17th century . These telescopes use lenses and are based on the principle of Refraction . These first telescopes were used for both astronomical and terrestrial purposes.
The Reflecting Telescopes use mirrors to gather and focus light . These are the widely used telescopes now , invented within a few decades of the first refractive telescope. In fact it was Isaac Newton who invented the first mirror telescope in 1668. The design built by him is known as The Newtonian Reflector.
The term Telescope was coined in 1611 by the Greek mathematician Giovanni Demisiani for one of the Galileo Galilei’s instruments presented at a banquet at the Accademia dei Lincei. In Starry Messenger (An astronomical pamphlet by Galileo) Galileo had used the term Perspicilium.
Earliest existing record of a telescope was a 1608 patent submitted to the government in Netherlands by a spectacle maker Hans Lippershey for a refracting telescope. Galileo heard about it and built his own version in 1609 and observed farthest planet as Jupiter. He also proved the theory of Copernicus , according to which Planets revolve around the Sun.
THE MODERN SPACE TELESCOPES
The atmosphere of our planet hindered astronomical observations as air refracts the images of heavenly bodies a number of times which makes the image less clear. To avoid this, an idea of space telescope was proposed in 1948. Later on 24 April 1990 The Hubble Space Telescope was launched succesfully, which was the first Space Telescope and disclosed hundreds of secrets of the Universe. Now several Space Telescopes have been invented, but Hubble is the most famous of them.
• Copernicus was the first person to propose that Earth revolves around the Sun.
• Andromeda is the nearest galaxy to The Milky Way lying at a distance of 2.357 million light years.
• Ganymede, the moon of Jupiter is the largest moon of out solar system with a diameter of 5268 km.
• Jupiter is the largest planet of our solar system. It can fit 1300 Earths inside it.