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