Lippershey filed application for a patent on the 25th of September 1608 i.e. a few weeks earlier to Jacob Metius who was also an instrument maker and optician in a city in the northern part of the Netherlands. Although he failed to receive a patent but was handsomely rewarded by the Dutch government for copies of his design. The telescope invented by Lippershey had a magnification of just 3x.
Another spectacle-maker Zacharias Jansen might prove a more lawful claim to have invented the telescope decades after the initial claims by Lippershey and Metius..
Galileo was the first person to use a telescope for the purpose of astronomy in 1609. In 2009 it completed a total of 400 years so celebrated as the International Year of Astronomy.
The Dutch diplomat William Boreel, who was apparently known to both Jansen and Lippershey in Middleburg during his youth, claimed that Lippershey stole his ideas from Jansen. Boreel was only being overzealous in his support of Jansen. There is no real evidence that Lippershey did not develop telescope independently.
Regardless of the inventor, most of the earliest versions of the telescope used a curved lens made of polished glass at the end of a tube to magnify objects to a factor of 3x.
Galileo had heard of the "Dutch perspective glass" by means of which distant objects appeared nearer and larger and constructed his own version of it without ever seeing one and stated that he solved the problem of the construction of a telescope in one night.
Instead of the initial 3 power magnification, he crafted a series of lenses that in combination magnify things by 8, 20 and eventually 30 times.
He took it to Venice where he delivered the details of his invention to the public and presented the instrument itself to the Senate. Galileo may thus claim to have invented the telescope independently, although Galileo's immense improvement of the instrument overshadowed to a great degree the credit due to Lippershey as the original inventor.
The lens telescope is still in use today in smaller telescopes, but many larger and more powerful telescopes use a reflective mirror and eyepiece combination that was initially invented by Isaac Newton called a “Newtonian” telescope after its inventor.
These types of telescopes have a polished mirror at the end of a tube, which reflects the image into an eyepiece at the top of the tube.