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 — 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
^
Rashed, Roshdi (September 1990). "A Pioneer in Anaclastics: Ibn Sahl on Burning Mirrors and Lenses". Isis. 81 (3): 464–491. doi:10.1086/355456. JSTOR233423. S2CID144361526.
^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.
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. PMID11721819. S2CID8185797.
Stars
Spaceflight
Outer space
Solar System