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3500 BCE
Phoenicians discover glass
Phoenicians cooking on sand discover glass. -
424 BCE
Aristophanes
Aristophanes uses a glass sphere filled with water to start fires. Lenses would not be used to study the stars for 2000 years. -
1400
Convex Lenses
Convex lenses to correct farsightedness are developed. -
1500
Concave lenses
Concave lenses to correct nearsightedness are developed. -
Hans Lippershey
In the Netherlands, Hans Lippershey discovers that holding two lenses up some distance apart bring objects closer. He applies for a patent on his invention. This is the first documented creation of a telescope. The patent to Lippershey is denied. -
Galileo
Galileo, after simply hearing that the device was invented, builds several telescopes of his own and turns them toward the heavens. -
Telescope
The term "telescope" is coined by Prince Frederick Sesi at a reception where Galileo is demonstrating his instruments. -
Telescope using a concave primary mirror
James Gregory designed a telescope using a concave primary mirror concave ellipsoidal secondary mirror. The first mirror gathers the light and reflects it onto the secondary. The secondary mirror focuses the light back through a hole in the primary mirror. This is the basis for many telescopes made today, but the opticians of his time were not able to produce mirrors of high enough quality to give good results. -
Reflecting Telescope
Newton produces the first successful reflecting telescope, using a two-inch diameter concave spherical mirror, a flat, angled secondary mirror, and a convex eyepiece lens. -
Johannus Hevelius
Johannus Hevelius realized that the longer the telescope was, the closer together the different colored points of light would be at the focal point, yielding a sharper image. He constructs a telescope 140 feet long which probably gave very sharp images.