The History of Astronomy in tabular form:
the crucial quarter millennium 1500 to 1750 CE

Around 1500 Astronomical observing gets interesting again for the community. 2:117
Ca. 1508 Copernicus has already "gotten it", but his Commentariolus - with a heliocentric world view, which he starts writing around this year - is not published, just distributed to friends (making the rounds by 1514 when the text is finished). 1:49, 7:28, 10
1508 Did Leonardo da Vinci built a working Galilean-style telescope that year - and even use it astronomically? A paper found in the 1930's seems to imply that - other strongly contest it, and few even note the possibility today. 15, 16
1516 This year's edition of a book by Johannes de Sacrobosco assumes enormous distances of the planets and esp. the starry spheres from the Earth (later authors have them much closer). 2:141
1522 Copernicus publishes a short critique of Werner's De motu octavae sphaerae: his only astronomical publication apart from De Revolutionibus. 7:47
Ca. 1530 onwards News about Copernicus' work begins to spread, probably based on the Commentariolus; the Vatican knows about it ca. 1533. 2:128, 7:52
Ca. 1532 Copernicus completes manuscript of De Revolutionibus, but it isn't published for another decade and undergoes multiple revisions until ca. 1539. By 1535 some of the tables are already used by others. 2:128, 7:52-3
1535 Oldest known "Parillenmacherordnung" regulating the prodcuction of eyeglasses (in Germany) - there are bad but also already quite good glasses around in the early 16th century. 14:103
1538 Girolamo Fracastoro publishes the discovery that comet tails always point away from the Sun. (Petrus Apianus does the same in 1540.) Insight that this is not exactly true comes from the comet of 1588. 1:50, 2:170-1, 3:115
1538 Girolamo Fracastoro writes in "Homocentrica" about the telescopic effect when combining two lenses - but it is uncertain whether he could use it to improve the angular resolution over the nake eye, thus making a telescope in its true sense. 14: 106+112
1539 Rh(a)eticus learns directly from Copernicus about his views, publishes first reports about them (Narratio primo) the following two years. 1:49, 7:41-2 + 53-4
1540 Alessandro Piccolomini publishes the first stellar atlas where the stars are labeled with letters. 1:51
Early 1543 Publication of De revolutionibus orbium coelestium by Copernicus who dies the same year (May 24). 1:49, 2:123, 7:44-7 +54-7
1546 Tycho Brahe born. 2:165-6
1550 Geronimo Cardano shows via parallax that comets reside far outside the Earth's atmosphere. Further work in that direction by Wilhelm & Rothmann in 1585, but the idea that comets are astronomy takes hold only in the 17th century. 1:50, 2:169
1551 Erasmus Reinhold - working with the math (but ignoring the physics) of De Revolutionibus - publishes the Tabulae Prutenicae of planetary position, replacing the outdated Alfonsinian tables. 1:51, 2:136, 7:65-6
1556 Robert Recorde writes about Copernicus in a popular book in England, The Castle of Knowledge, which discusses the ideas in dialogue format. 2:139, 7:82
1557 The French poet Pontus de Tyard publishes a book about the Universe that mentions Copernicus but doesn't take sides. 7:83
1560 First observatory of modern times founded at the Kassel castle - one of the two centers of astronomical research in the 2nd half of the 16th century (the other one will be on Hven). Careful observations commence in 1561. 2:161+4
1560 A solar eclipse triggers Brahe's interest in astronomy: once can predict these things! 11:4
1561 Copernicus' findings already being taught at Salamanca University - but only the math, not the physics & philosophy (as usual these days). 2:138
1563 August Tycho Brahe observes a close conjunction of Jupiter and Saturn, not predicted properly, and decides to do better. 9:26, 11:4
1564 Feb. 15 Galileo Galilei born. 8:75
1566 Wilhelm IV (of Kassel Obs.) compiles a catalogue of 58 stars - the first since antiquity. Work continued only in 1585. 2:162
1566 Because of high demand, a 2nd edition of De Revolutionibus comes out, including Rheticus' - more accessible - Narratio Prima of 1541. 7:81
Ca. 1570 Calendar makers start to use the Tabulae Prutenicae because of their improved precision, often crediting not only Reinhold but also Copernicus. 2:137
1571 Dec. 27 Johannes Kepler born. 9:104
1571 Possible reference to a working telescope in Thomas Digges' Pantometria, which may describe a reflector - taken moderately serious by historians. Certainly there never was a mass production. 4:338-9, 5:7, 6, 14:106
1572 Nov. 11 Bright supernova in Cassiopeia (visible until 1574), shakes belief in static sky (til then, only planets and comets were known to do something); Tycho Brahe observes it in detail and publishes De nova stella already in 1573, becomes famous. 1:52-3, 2:166, 7:86-7, 11:4
1575 April Young Tycho Brahe visits Kassel Observatory; data exchange and discussions with Wilhelm from 1585 in voluminous letters which Brahe publishes as a book in 1596. 2: 163-4
1576 Tycho Brahe builds his first observatory on Hven, Uraniborg (second one follows in 1584) - the 2nd major center of astronomical research (after Kassel). 1:53, 2:166-7
1577 Tycho's observations of a bright comet show that it is at least 6 times farther than the Moon. 3:117, 9:27
1576 Leonard & Thomas Digges publish their Prognostication euer lastingue, containing a pretty modern cosmology (with an infinite universe - because they saw more stars than the eye in their alleged telescopes?), and in A perfit description of the caelestiall orbes Thomas Digges staunchly supports copernicanism. 1:50, 2:139, 4:341, 7:84-5
1581 Galilei tries in vain to measure the speed of light with terrestrial experiment; can only conclude that it must be huge. 1:59
1582 Oct. 4 = 14 Major calendar reform by pope Gregor XIII who introduces (via Inter gravissimas on Feb.24) a new system developped by Christoph Clavius - whose scientific arguments are only published in 1588. 1:53, 2:156, 7:37
1584 Giordano Bruno argues in La cena delle ceneri for the Copernican system and in the same year in Dell' infinito, universo e mondi even removes the Sun from the center of the Universe - with the possibility of other planetary systems. No one picks up that idea. 1:52, 2:193-4
Probably/around 1585 William Bourne describes possible British telescopes in a brief "Treatise" that describes - in some detail - a "perspective glass". But it seems likely that he wrote the paper before even trying to actually build one. 4:339, 14:106-108
1586 Rothmann speaks out in favor of the Copernican system, 10 years after Digges and 10 years before Kepler's Mysterium cosmographicum. 2:171
1588 Brahe publishes his own cosmological system, dropping the idea of solid celestial spheres along the way - the Tychonian model will be the most popular one in the 1st half of the 17th century. 2:167-8, 7:87-9
1588 Kepler's teacher Michael Mästlin still uses the Ptolemaic system in his Epitome Astronomiae, but in later editions he mentions the Copernican, too - thus it was common knowledge in universities. 7:82
1589 Giovan Battista della Porta describes a Galilean-style telescope in his "Magia naturalis"; it seems he built some for friends with bad eyesight. 14:108
1590/91 Galileo experiments about free fall. 8:8 + 75
1592 First ever nova explosion recorded in history, in the constellation Cetus. 1:53
1596 Kepler publishes the – mostly speculative - Mysterium Cosmographicum, in which he tries to prove Copernicus through philosophy; Mästlin adds the Narratio Prima to the book. Brahe gets interested in Kepler. 2:175, 7:82-3, 9:16-22, 11:5-6
1596 Helisäus Röslin uses the comet of that year to argue in detail for its cosmic nature. 2:172-3
1596 Aug. 13 David Fabricius discovers the star Mira near its maximum, then it's seemingly gone; he sees Mira again in 1609, but only in 1639 it is recognized as one and the same variable star with a large amplitude. 1:53
1597 Aug. 4 Galilei writes to Kepler that he has found a lot of evidence for the Copernican view but hasn't published it yet - Kepler asks him to do that, Galilei declines: He wants real data first. 1:51, 8:14
1600 Feb. 4 Kepler and Tycho - after 'observing' each other for some time - finally meet in person. Kepler joins his assistants. 9:23-5 + 28
1600 Feb. 11 Murder of Giordano Bruno by the church authorities after 6 years in jail. 1:52, 7:90-1
1600 July 10 Kepler experiments with a pinhole camera during a solar eclipse, starts thinking about ray optics. 2:199, 9:38
1600 In De magnete et de magno magnete tellure William Gilbert treats the Earth as a giant bar magnet and has it rotate around its axis. 2:181, 7:89
1601 Oct. 24 Tycho Brahe dies, Kepler succeeds him in Prague and obtains his observing data. 2:175, 9:29
1603 Johann Bayer publishes the Uranometria, the first Atlas of the complete sky, with over 2000 stars, labelled with greek letters. 1:54, 2:228
1604 Kepler publishes his Optica alias Paralipomena (finished in 1603), a comprehensive book about light and optics. 9:39-45
1604 Another bright supernova, this time observed by Kepler (who writes about De stelle nova in 1606) and Galilei (who gives public talks about the star in 1604). Johannes Krabble treats the supernova as a comet and derives a lot of (nonsensical) results from his observations in this light. 2:173-4, 8:75, 9:27
1607 May 28 Kepler observes a sunspot with a camera obscura - and thinks its Mercury in transit. Spots on the Sun were just not allowed ... 2:187
1607 Kepler observes Halley's comet - and uses his data to argue for comets moving in straight lines through the solar system ... 3:132
1608 summer/fall First proven existence of telescopes; Dutch try to patent them (and fail, e.g. Lipperhey's application of Oct. 2). Thomas Harriot uses a telescope to make drawings of the lunar surface in July/August. The invention is noted several times in Europe in September, spreads all over the continent until spring of 1609. 1:57, 2:188, 4:335, 5:7, 6, 14:109-113 + 120, 17:127
1609 Kepler's Astronomia Nova contains the first two laws of planetary orbits; the work was written between 1600 and 1606. 1:55, 7:93, 9:30-6, 11:6-13
1609 fall Galilei starts to build and use telescopes (about which he learned first in May) for astronomical observations of all sorts, from November oder December. He resolves the Milky Way and a few deep sky objects and studies the lunar surface. 1:57, 5:7-8, 6, 8:75
1610 Galilei discovers the moons of Jupiter in January (several others see them almost simultaneously; Kepler observes them with a borrowed telescope in September), the phases of Venus (which approaches inferior conjunction in 1611) and something close to Saturn (cannot resolve the rings). Publishes some of his observations already on 12 March in the Sidereus Nuncius, but the news had already spread by then. Kepler offers support with the Dissertatio cum S.N. 1:57+58, 2:183+5 + 199, 5:8-9 + 30, 6, 7:95-9, 8:75, 9:54-7, 17:127+130
1610 December Galilei's student Benedetto Castelli realizes that the phases of Venus - which is becoming more and more of a crescent - are a first major argument for the heliocentric view. 2:184
1611 February There are still grave doubts among some about Galileo's telescopic observations as many try in vain to repeat them with inferior optics - but others have succeeded and support the Sidereus Nuncius. 17:133-134
1611 Kepler describes his telescope design in Dioptrice, the first modern optics textbook (written in Sep./Oct. 1610) - replaces the inferior "Galilean" design in the 1630s. 2:199, 5:9, 9:58-9
1612 Clavius adds some lines about the new telescopic discoveries to the new edition of Sacrobosco's Sphere - and leaves the interpretation to "the astronomers" while otherwise sticking to Ptolemy. 17:140-141
1612 Dramatic early discoveries with the telescope come to an end this year; systematic research takes over. Several astronomers have discovered the sunspots; priority is being fought over ... 2:199 + 201, 8:32
1612 Dec. 15 Marius observes the Andromeda galaxy and cannot resolve it into individual stars. 2:200
1614 Simon Marius publishes tables of the Jovian moons that are better than Galilei's - who doesn't like that at all ... 2:184-5
1616 February The catholic church puts Copernicus' De revolutionibus on the index - kind of. And Galilei is banned from spreading the view. 1:57, 2:189, 8:75
1617 Kepler starts publishing planetary ephemerides, much more precise than available before. 2:177
1617 Galilei tries - in vain - to measure the stellar parallax in the Mizar system 12
1618 Kepler writes down his 3rd law of planetary motion, published a year later in Harmonice mundi libri V. 1:55, 9:82-9
1618 Three comets in one year reignite the debate about their nature. Orazio Grassi puts them in regular orbits around the Sun, just like the planets - but Galilei attacks him in 1623 in Il Saggiatore proclaiming comets optical illusions ... 3:119, 8:39
1618-21 In Epitome astronomiae Copernicanae (banned by the Vatican in 1619) Kepler defends the Copernican view and thinks about physical forces. Also postulates stream of particles flowing from the Sun to explain comet tails. 1:57, 2:181-2, 9:53 + 104
Around 1620 Start of the "Maunder minimum" of solar activity (until ca. 1725). 1:74
1620 May 16 Index congregation "improves" De Revolutionibus by striking references to true motion of Earth. Cannot ban the book completely because of its role in the popular Tabulae Prutenicae, used e.g. in the calendrical reform. 2:189-90
Ca. 1621 Willebrord Snellius discovers the laws of refraction, after Harriot almost got them first. 2:199, 4:336
1627 Kepler publishes his Tabulae Rudolphinae with the most precise planetary positions so far: This helps raise the popularity of the Copernican system and people begin to wonder whether its more than just a math tool. An 1800-year gap between astronomy & physics begins to close. 1:54, 2:179+80, 9:90-4
1630 Nov. 15 Johannes Kepler dies. 9:96
1630 Christoph Scheiner publishes Rosa Ursina sive Sol, the first major book on solar research. 2:186-7
1631 First observation of a planetary transit - by Mercury – over the Sun's disk (as predicted by Kepler in 1627). 1:56
1632 The catholic church puts all major works by Galilei on the index, including the Dialogo published this year. Galilei proposes parallax measurements to get stellar distances. 1:57, 2:273, 8:43-52 + 75
1633 June 22 Galilei is forced to publicly abandon Copernicanism, after two months of "trial" in Rome. 8:54-61 + 75
1634 Posthumously Kepler's science fiction story Somnium is published, in which he also proves the existence of lunar mountains. 9:60 + 97-103, 13
1637 First observatory with a telescope built in Copenhagen. (But at Leiden Obs. a telescope was already in use in 1632.) 1:63, 9:59
1638 Galilei - already blind - publishes his Discorsi about mechanics and dynamics. 8:70+2
1639 Nov. 24 First observation of a transit of Venus by Jeremiah Horrocks (and a few others). 1:56
Around 1640 William Gascoigne combines a Keplerian telescope with crosshairs. 2:214
1642 Jan. 8 Galileo Galilei dies, never having acknowledged Kepler's breakthrough of elliptical orbits (although we know that he knew Kepler's laws). 2:177, 8:73, 9:53
1647 Johannes Hevelius publishes the first detailled map of the Moon in Selenographica; before that, there was little interest in lunar cartography. 1:58, 2:183 + 203
1650 Discovery of the first double star by Giovanni Riccioli who splits Mizar. 1:59
1650 Maria Cunitia publishes Urania Propitia... Das ist: Newe und langgewünschete, leichte Astronomische Tabelln - one of very few women of note in astronomy before 1700. 2:179
1651 In Almagestum novum Riccioli describes the Tychonian system in ample detail - in 1500 pages he tries to reconcile the old and new views about the Universe. 2:168, 7:89
1656 March Christiaan Huygens understands the rings of Saturn as a free-floating disk; a year earlier he had discovered Titan. 1:59, 2:201
1656 Huygens builds a telescope 23 feet long, with a magnification of x100 and 17' FOV - typical for that era. (In the 1670s Hevelius builds a 140-foot telescope.) 6
1656 Nov. 8 Edmond Halley is born. 3:124
1657 Huygens invents the pendulum clock. 8:31
1659 First observation of surface structures on another planet, by Christiaan Huygens on Mars; in 1666 Cassini discovers its polar caps. (1:54)
Around 1660 Measuring devices advanced enough to get the angular diameters of the planets. 2:214
1660 "Royal Society of London for Improving Natural Knowledge" founded. 3:125
1663 James Gregory orders a reflector made to his new design - but technology isn't up to it yet. 4:335
1664 Robert Hooke discovers the Great Red Spot on Jupiter, finds planet's rotation around an axis. 1:55, 2:201
1664 Breakthrough in compound eyepiece design by Giuseppe Campani, setting the standard for 100+ years. 5:10 + 48
1666 Isaac Newton find the laws of motion – but doesn't publish them until 1687. 1:60
1667 Micrometer introduced for precise telescopic measurements. 1:62
1667 The national observatory of France is built in Paris – the oldest one still in use. 1:63, 2:204-5
1668 Newton invents the reflecting telescope that has no color problems. Gets him into the Royal Society in 1672; principle described in detail in 1704 in Optick. 1:62, 2:217
1668 Hevelius classifies comets by their tail shape in his Cometographia. 3:94
1671 First measurement of the parallax of Mars by Giovanni Cassini – the solar system finally gets a rough absolute scale. 1:59, 2:215
Ca. 1672 Cassegrain builds the first reflector telescope of his design. 1:63
1672 Newton publishes his famous paper on light and colors, showing that white light is a mix of all. 6
1674 Halley theorizes that the biblical flood was caused by a comet impact. 3:106
1675 Ole Roemer determines the speed of light by observing events of the Jovian moons. 1:59
1675 Cassini discovers the major gap in Saturn's rings, nowadays known as the Cassini gap. 2:206
1675 Aug. 10 The Royal Greenwich Observatory is built near London, mainly for naval use - astronomy funding is no longer motivated by astrology but by usefulness. In March Halley had introduced himself - and impressed - the first Astronomer Royal, John Flamsteed. 2:207-9, 3:125-6 + 138
After ca. 1675 Telescopes have become so long that no tube is used anymore: the age of the aerial telescope. Technology reaches its limit. 6
1679 Jean Picard starts publishing the annual Connaissance des temps, ou calendrier et ephemerides which not only contains ephemerides but also current research results. 2:205
1679 May Halley is sent to Hevelius by the Royal Society to compare competing astrometrical techniques - no clear winner found. 3:130
1680 Nov. 14 First telescopic discovery of a comet by Gottfried Kirch. 2:223
1682 Great Comet of the year leads Halley to the discovery of its periodic orbit. Predicts its return for 1759 – when it is found indeed and becomes known as "Halley's Comet" ever since. 1:57
1684 Halley visits Newton, looking for an answer why orbits are elliptical, learns to his amazement that Newton has the answer already - but misplaced the calculations! 2:217-8, 3:133
1687 Newton publishes his laws of motion - under Halley's pressure - in the Philosophiae naturalis principia mathematica alias Principia; convincing physics enable the breakthrough of the heliocentric system. 1:60, 2:180 + 218-21, 3:133-6, 11
1689 The transit telescope for astrometry is introduced by Roemer. 1:64, 2:216
1690 Hevelius' widow publishes a stellar catalogue that again improves on the one from Kassel and Brahe' - although Hevelius' measurements had not used telescopes. 2:203, 3:131
1690 Dec. 23 Flamsteed sees Uranus but doesn't realize it - thus discovery by Herschel only in 1781. 2:246
1704 Roemer invents the meridian circle for more precise astrometry. 1:64, 2:216
1705 Halley predicts the return of the Great Comet of 1682 for ca. 1758 after identifying it with the comets of 1607 (seen e.g. by Kepler) and 1531 (seen by Apianus). 1:65, 2:225, 3:146-8
1715 April 22 Total Solar Eclipse in Great Britain – predicted in great detail by Halley, track off by only 32 km. Public informed before event, using it for research, too. 1:68, 3:140-1
1718 Discovery of the proper motion of "fixed" stars by Halley who analyzed old and new tables. 1:66
1723 Hadley presents an excellent and easy-to-use reflector telescope. 2:237
Ca. 1724 Jai Singh II. starts building giant naked-eye observatories in India, the first one in Delhi. 1:73
1728 Discovery of the aberration of starlight by James Bradley (published in 1729). A nice direct confirmation of copernicanism, better even than small parallax measurements - as stated by Bessel in 1848. 1:70, 2:273-4
1730s onwards Telescope magnification increases again after decades of stasis as the reflector takes over. 6
1731 Halley develops a method to get the geographical longitude at sea from astronomical measurements. 2:226
Ca. 1733 Invention of the achromatic telescope by an English amateur, Chester Moor Hall – ignored by the 'experts' until 1758 (when Dollond is granted a patent) because 'it cannot be true' and is not published properly ... 1:71-72, 2:237-8
1734 James Short finally manages to build a working Gregory reflecting telescope. 4:336
1736/37 The flattening of the Earth at its poles is finally measured without doubt, after earlier erroneous data (1718) had 'proven' an equatorial flattening, while still earlier data (1672/3) had gotten it right. Newtonian physics rule, after all. 1:69, 2:215, 3:128-9
1740 James Short builds reflecting telescopes following a design by Cassini. (1:60)
1742 Jan. 14 Death of Halley at 85. 3:147-8
1742 Connection between aurorae and Earth's magnetic field established. 1:74-75
1747 Bradley discovers the nutation of the Earth's axis. 1:76-77
Around 1750 Existence of Milky Way and off-center location of the Sun postulated by Thomas Wright - who inspires Kant to think even further in 1755. 1:77+78, 2:234


1: F.R. Paturi, Harenberg Schlüsseldaten Astronomie, Harenberg Lexikon Verlag, Dortmund 1996
2: J. Hamel, Geschichte der Astronomie, Birkhäuser, Basel/Berlin/Boston 1998
3: E. Aguirre & I. Joson, Halley's Comet - the 2nd coming this century, Basic Media Systems, Manila 1985
4: C. Ronan, The origins of the reflecting telescope, Journal of the BAA 101 #6 [1991] 335-42
5: A. Van Helden, Catalogue of Early Telescopes, Istituto e Museo di Storia della Scienza, Firenze 1999
6: A. Van Helden, Galileo's Telescope, Connexions Module m11932 [2004]
7: W. Shea, Nikolaus Kopernikus, Spektrum der Wissenschaft Biografie 1/2003
8: B. Cimino & S. Neumann, Galilei und seine Zeit, Emil Volmer Verlag, Wiesbaden 1966
9: A.M. Lombardi, Johannes Kepler, Spektrum der Wissenschaft Biografie 4/2000
10: J. Leisen, Der Commentariolus in der Tradition der antiken Astronomie, Preprint der Uni Mainz
11: H. Chang & W. Hsiang, The epic journey from Kepler's laws to Newton's law of universal gravitation revisited, Preprint
12: C. Graney, Letter to the Editor of Sky and Telescope Concerning Galileo's Observations of Mizar, eine Art Reprint
13: G. Christianson, Kepler's Somnium: Science Fiction and the Renaissance Scientist, Science Fiction Studies #8 [1976]. Also: Somnium for Schools and more from the Kepler Society (both in German)
14: R. Willach, Der lange Weg zur Erfindung des Fernrohres, in: Die Meister und die Fernrohre, Das Wechselspiel zwischen Astronomie und Optik in der Geschichte, Acta Historica Astronomiae 33 [2007] 34-126 (gibt's seit 2008 auch in Englisch; dieser Review fasst einige - aber nicht alle! - Kernthesen gut zusammen)
15: J. Schumann, Das Leonardo-Teleskop - 101 Jahre vor Galilei, Sternzeit 17 [2/2001] 50-59
16: K. Veltman, Continuity and Discovery in Optics and Astronomy, Paper
17: E. Reeves & A. van Helden, Verifying Galileo's discoveries: telescope-making at the Collegio Romano, in Die Meister und die Fernrohre, Das Wechselspiel zwischen Astronomie und Optik in der Geschichte, Acta Historica Astronomiae 33 [2007] 127-141

Further websites of interest

Galileo's Telescope about the Florence exhibition
Antique Telescopes and telescope history
Refracting Telescopes prior to 1775 Catalog
Galileo's First Jupiter Observations
What was the Copernican Revolution? (Exploring the Cosmos - An Introduction to the History of Astronomy
Meilensteine der Wissenschaft
History of Telescopes
Reviews of books on the (early) history of the telescope
The history of the telescope & the binocular - Early Binocular History
The Atlas Coelestis (1742) of Johann Gabriel Doppelmayr (comparing world systems)
Die Kopernikanische Wende
Wann ist das Mittelalter

Compiled by Daniel Fischer (first nine sources: Dec. 12, 2007; more added: Jan. 12+15 + Feb. 18 + Mar. 4+14 + Apr. 7, 2008)