Timeline of telescope technology

BC

2560 BC to 1 BC

• c.2560 BC–c.860 BC — Egyptian artisans polish rock crystal, semi-precious stones, and latterly glass to produce facsimile eyes for statuary and mummy cases. The intent appears to be to produce an optical illusion.
• 424 BC Aristophanes "lens" is a glass globe filled with water.
• 3rd century BC Euclid is the first to study reflection and refraction using mathematical theorems based on the fact that light travels in straight lines

AD

1 AD to 999 AD

• 2nd century AD — Ptolemy wrote about the properties of light including: reflection, refraction, and colour.
• 984 — Ibn Sahl completes a treatise On Burning Mirrors and Lenses, describing plano-convex and biconvex lenses, and parabolic and ellipsoidal mirrors.

1000 AD to 1999 AD

• 1011–1021 — Ibn al-Haytham writes the Kitab al-Manazir
• 1230–1235 — Robert Grosseteste describes the use of 'optics' to "...make small things placed at a distance appear any size we want, so that it may be possible for us to read the smallest letters at incredible distances..." in his work De Iride.
• 1266 — Roger Bacon mentions the magnifying properties of transparent objects in his treatise Opus Majus.
• 1270 — Witelo writes Perspectiva — "Optics" incorporating much of Kitab al-Manazir.
• 1285–1300 spectacles are invented.
• 1570 — The writings of Thomas Digges describes how his father, English mathematician and surveyor Leonard Digges, made use of a "proportional Glass" to view distant objects and people. Some, such as the historian Colin Ronan, claim this describes a reflecting or refracting telescope built between 1540 and 1559 but its vague description and claimed performance makes it dubious.
• 1586 Giambattista della Porta writes "...to make glasses that can recognize a man several miles away" It is unclear whether he is describing a telescope or corrective glasses.
• 1608 — Hans Lippershey, a Dutch lensmaker, applies for a patent for a perspective glass "for seeing things far away as if they were nearby", the first recorded design for what will later be called a telescope. His patent beats fellow Dutch instrument-maker's Jacob Metius's patent by a few weeks. A claim will be made 37 years later by another Dutch spectacle-maker that his father, Zacharias Janssen, invented the telescope.
• 1609 — Galileo Galilei makes his own improved version of Lippershey's telescope, calling it a "perspicillum".
• 1611 — Greek mathematician Giovanni Demisiani coins the word "telescope" for one of Galileo Galilei's instruments presented at a banquet at the Accademia dei Lincei.
• 1611 — Johannes Kepler describes the optics of lenses, including a new kind of astronomical telescope with two convex lenses.
• 1616 — Niccolo Zucchi claims at this time he experimented with a concave bronze mirror, attempting to make a reflecting telescope.
• 1630 — Christoph Scheiner constructs a telescope to Kepler's design.
• 1650 — Christiaan Huygens produces his design for a compound eyepiece.
• 1663 — Scottish mathematician James Gregory designs a reflecting telescope with paraboloid primary mirror and ellipsoid secondary mirror. Construction techniques at the time could not make it, and a workable model was not produced until 10 years later by Robert Hooke. The design is known as 'Gregorian'.
• 1668 — Isaac Newton produces the first functioning reflecting telescope using a spherical primary mirror and a flat diagonal secondary mirror. This design is termed the 'Newtonian'.
• 1672 — Laurent Cassegrain, produces a design for a reflecting telescope using a paraboloid primary mirror and a hyperboloid secondary mirror. The design, named 'Cassegrain', is still used in astronomical telescopes used in observatories in 2006.
• 1674 — Robert Hooke produces a reflecting telescope based on the Gregorian design.
• 1684 — Christiaan Huygens publishes "Astroscopia Compendiaria" in which he described the design of very long aerial telescopes.
• 1720 — John Hadley develops ways of aspherizing spherical mirrors to make very accurate parabolic mirrors and produces a much improved Gregorian telescope
• 1721 — John Hadley experiments with the neglected Newtonian telescope design and demonstrates one with a 6-inch parabolic mirror to the Royal Society.
• 1730s — James Short succeeds in producing a Gregorian telescopes to true paraboloidal primary and ellipsoidal secondary design specifications.
• 1733 — Chester Moore Hall invents the achromatic lens.
• 1758 — John Dollond re-invents and patents the achromatic lens.
• 1783 — Jesse Ramsden invents his eponymous eyepiece.
• 1803 — The "Observatorio Astronómico Nacional de Colombia " is inaugurated as the first observatory in the Americas in Bogotá, Colombia.
• 1849 — Carl Kellner designs and manufactures the first achromatic eyepiece, announced in his paper "Das orthoskopische Ocular".
• 1857 — Léon Foucault improves reflecting telescopes when he introduced a process of depositing a layer of silver on glass telescope mirrors.
• 1860 — Georg Simon Plössl produces his eponymous eyepiece.
• 1880 — Ernst Abbe designs the first orthoscopic eyepiece.
• 1897 — Largest practical refracting telescope, the Yerkes Observatorys' 40 inch refractor, is built.
• 1900 — The largest refractor ever, Great Paris Exhibition Telescope of 1900 with an objective of 49.2 inch diameter is temporarily exhibited at the Paris 1900 Exposition.
• 1910s — George Willis Ritchey and Henri Chrétien co-invent the Ritchey-Chrétien telescope used in many, if not most of the largest astronomical telescopes.
• 1930 — Bernhard Schmidt invents the Schmidt camera.
• 1932 — John Donovan Strong first “aluminizes" a telescope mirror a much longer lasting aluminium coating using thermal vacuum evaporation.
• 1944 — Dmitri Dmitrievich Maksutov invents the Maksutov telescope.
• 1967 — The first neutrino telescope opened in Africa.
• 1970 — The first space observatory, Uhuru, is launched, being also the first gamma-ray telescope.
• 1975 — BTA-6 is the first major telescope to use an altazimuth mount, which is mechanically simpler but requires computer control for accurate pointing.
• 1990 — Hubble Space Telescope was launched into low Earth orbit

2000 CE to 2025 CE

• 2003 — The Spitzer Space Telescope, formerly the Space Infrared Telescope Facility, is an infrared space observatory launched in 2003. It is the fourth and final of the NASA Great Observatories program
• 2008 — Max Tegmark and Matias Zaldarriaga created the Fast Fourier Transform Telescope.
• 2022 — The James Webb Space Telescope is launched by NASA.