The following timeline lists the significant events in the invention and development of the telescope.
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.[1][2][3]
424 BC Aristophanes "lens" is a glass globe filled with water.(Seneca says that it can be used to read letters no matter how small or dim)[4]
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[5]
984 — Ibn Sahl completes a treatise On Burning Mirrors and Lenses, describing plano-convex and biconvex lenses, and parabolic and ellipsoidal mirrors.[6][7]
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..." ("Haec namque pars Perspectivae perfecte cognita ostendit nobis modum, quo res longissime distantes faciamus apparere propinquissime positas et quo res magnas propinquas faciamus apparere brevissimas et quo res longe positas parvas faciamus apparere quantum volumus magnas, ita ut possible sit nobis ex incredibili distantia litteras minimas legere, aut arenam, aut granum, aut gramina, aut quaevis minuta numerare.") in his work De Iride.[9]
1266 — Roger Bacon mentions the magnifying properties of transparent objects in his treatise Opus Majus.
1270 (approx) — Witelo writes Perspectiva — "Optics" incorporating much of Kitab al-Manazir.[10]
1570 — The writings of Thomas Digges describes how his father, English mathematician and surveyor Leonard Digges (1520–1559), 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.[12][13][14]
1586 Giambattista della Porta writes "...to make glasses that can recognize a man several miles away" [15] It is unclear whether he is describing a telescope or corrective glasses.[16]
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.[17]
A replica of Galileo's 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" (from the Greek τῆλε, tele "far" and σκοπεῖν, skopein "to look or see"; τηλεσκόπος, teleskopos "far-seeing") for one of Galileo Galilei's instruments presented at a banquet at the Accademia dei Lincei.[18][19][20]
1611 — Johannes Kepler describes the optics of lenses (see his books Astronomiae Pars Optica and Dioptrice), including a new kind of astronomical telescope with two convex lenses (the 'Keplerian' telescope).
1616 — Niccolo Zucchi claims at this time he experimented with a concave bronze mirror, attempting to make a reflecting telescope.
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'.
A replica of a second reflecting telescope Newton presented to the Royal Society in 1672 (the first one he made in 1668 was loaned to an instrument maker but there is no further record of what happened to it).[21]
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[22][23]
1721 — John Hadley experiments with the neglected Newtonian telescope design and demonstrates one with a 6-inch parabolic mirror to the Royal Society.[24]
1730s — James Short succeeds in producing a Gregorian telescopes to true paraboloidal primary and ellipsoidal secondary design specifications.[23]
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.
The Oldest Observatory in the Americas is found in Bogotá, Colombia (1803).
2003 — The Spitzer Space Telescope (SST), formerly the Space Infrared Telescope Facility (SIRTF), is an infrared space observatory launched in 2003. It is the fourth and final of the NASA Great Observatories program
^Enoch J (April 2000). "First known lenses originating in Egypt about 4600 years ago!". Hindsight. 31 (2): 9–17. PMID 11624467.
^Studies of the oldest Known Lenses at the Louvre (4600 Years Before the Present)
^Remarkable Old Kingdom Lenses and the Illusion of the Following Eye
^King 2003, p. 25
^King 2003, p. 26
^Rashed, Roshdi (September 1990). "A Pioneer in Anaclastics: Ibn Sahl on Burning Mirrors and Lenses". Isis. 81 (3): 464–491. doi:10.1086/355456. JSTOR 233423. S2CID 144361526.
^"Did the reflecting telescope have English origins?". 2002. Retrieved 2007-03-15.
^Ronan, Colin A. M.Sc. F.R.A.S. (1991). "Leonard and Thomas Digges". Journal of the British Astronomical Association. 101 (6). British Astronomical Association.
^Fred Watson (2006). Stargazer: The Life and Times of the Telescope. Da Capo Press. p. 38. ISBN 978-0-306-81483-9.
^Bologna University Department of Astronomy — TELESCOPES
^Rebecca Stefoff (2007). Microscopes and Telescopes. Marshall Cavendish. p. 17. ISBN 978-0-7614-2230-3.
^David Whitehouse (2009). Renaissance Genius : Galileo Galilei & H. Sterling Publishing Company, Inc. pp. 69–70. ISBN 978-1-4027-6977-1.
^archive.org "Galileo His Life And Work" BY J. J. FAHIE "Galileo usually called the telescope occhicde or cannocchiale ; and now he calls the microscope occhialino. The name telescope was first suggested by Demisiani in 1612"
^"The Schmidt Camera". October 2002. Archived from the original on 2007-03-24. Retrieved 2007-03-28.
^nmt.edu — New Mexico Institute of Mining and Technology — “Resurfacing the 100-inch (2,500 mm) Telescope” by George Zamora Archived 2008-10-13 at the Wayback Machine
^"The James Webb Space Telescope". NASA.
External links
Elliott, Robert S. (1966). "Electromagnetics" (Document). McGraw-Hill.
Wade, Nicholas J.; Finger, Stanley (2001). "The eye as an optical instrument: from camera obscura to Helmholtz's perspective". Perception. 30 (10): 1157–1177. doi:10.1068/p3210. PMID 11721819. S2CID 8185797.
King, Henry C. (2003). The History of the Telescope. Courier Dover Publications. ISBN 978-0-486-43265-6.
