OUTLINE OF 18TH CENTURY ASTRONOMY ------------------------------- John Pazmino NYSkies Astronomy Inc email@example.com www.nyskies.org 2003 August 5 initial 2012 July 16 current
At the Observing Group meeting of 12 July 2003 I presented an overview of astronomy during the 1700s. I had hand-written notes to cue me. Here are my notes in finished form, with many additional items suggested since then. I confine to items distinctly 'astronomy', leaving out collateral fields like chemistry, industry, biography, and general world affairs. Apart from minor editing and some addition of new items, the major change is the collapse of the categories for the entires. It got too fiddly to put an entry in a one category where it could be valid for several. Here, entries are now listed seriatim and divided by decade. I update this article irreguarly as readers advise me of new items of interest.
1700-1709 --------- 1700 - Roemer invents meridian transit telescope 1700 - Boyle, Lord of Orrery, invents hand-driven model of solar system 1700 - Delisle perfects celestial geodesy 1701 - England issues charts with compass variation contours 1702 - Haukshee shows that electrcity makes rarified air glow, hints at cause of aurora 1702 - Halley issues first map of geomagnetic field, first use of contour lines in cartography 1702 - Gregory writes first astronomy textbook with Newton gravity 1704 - Newton issues corpuscular theory of light 1705 - Halley proposes periodic comets, predicts return of 'Halley's comet' 1705 - Flamsteed issues 1st part of most accurate star catalog 1706 - Stannyan discovers prominences during solar eclipse 1708 - Jupiter's 'great red spot' reappears, gone since 1680s
1710-1719 --------- 1710 - end of Maunder sunspot drought on Sun 1718 - Halley discovers proper motion of stars 1712 - bootleg unverified Flamsteed catalog is issued 1713 - Newton issues updated 'Principia' 1714 - England opens contest for determining longitude 1714 - Leibniz proposes space & time can not be absolute 1715 - Halley discovers 'Baily's beads' during solar eclipse 1715 - Halley does first calcs of ground track of solar eclipse 1716 - Halley shows aurora rays converge by perspective effect and align with Earth magnetic field 1716 - France opens contest for determining longitude 1716 - Halley proposes Venus transit for fixing Earth-Sun distance 1718 - Cassini proposes Earth is prolate (it's really oblate) 1719 - Maraldi makes first detailed Mars map, fixes rotation 1719 - Maraldi explains changes of Mars polar caps as ice 1719 - Stupendous aurora erupts over Europe starting modern scientific study of northern lights
1720-1729 --------- 1720 - Halley studies 'Olber's paradox' 1721 - Berkeley proposes matter-space interaction 1722 - Graham discovers daily shift of geomagnetic feild 1722 - Hadley makes first practical reflector telescope 1724 - Maraldi shows corona is part of Sun, not Moon 1724 - Graham, also Celsius, discovers geomagnetic storm by violent agitation of marine compass 1725 - Flamsteed posthumously issues most accurate staratlas, uses 'Flamsteed' designations 1725 - Thiout builds clock for true, not mean, solar time 1727 - Schulze discoveres photochemical effect in silver nitrate. 1727 - Bradley discovers aberration as effect of light speed 1728 - Bianchini fixes Venus rotation (wrong, until spacecraft measurements in 1960s.) 1729 - Bouger invents photometer 1729 - Bouger describes light attenuation thru glass plates 1729 - Motte translates Newton's 'Principia' into English
1730-1739 --------- 1731 - Hadley, and Geoffrey, invents marine quadrant 1731 - Bevis discovers Crab Nebula, later catalogued by Messier 1732 - deMaupertuis proposes Earth is oblate, not prolate 1733 - Hall invents achromatic refractor 1733 - Celsius explains aurora borealis 1734 - France finally accepts Newton gravitation theory 1735 - deCondamine fixes curvature of Earth 1735 - Harrison invents mechanical clock for longitude 1736 - Euler applies differential equations to Newton mechanics 1737 - Bevis observes first planet-planet occultation, Venus over Mercury 1738 - Smith issues 'Opticks', 1st book on telescpe making 1738 - Delisle invents heliographic coordinate system 1739 - Winthrop starts first routine monitoring of sunspots 1739 - deMaupertuis fixes oblatitude of Earth 1739 - Halley confirms secular acceleration of Moon, first noticed in 1692
1740-1749 --------- 1740 - Short starts selling first commercial reflectors 1740 - Stukely discovers solstice alignment at Stonehenge 1740 - Bouguer discovers gravity variation around world 1742 - Celsius invents inverse centigrade temperature scale 1742 - Maclaurin explains spherical shape of planets 1743 - Christin invents 'Celsius' temperature scale 1743 - d'Alembert uses energy concept in Newton gravity theory 1743 - Clairaut clacs variation of gravity on oblate Earth 1744 - Pope allows Galileo's 'Dialogue ...' to publish only with his denial of Copernicus system in it 1744 - Cassini makes first national geodetic survey, in France 1744 - deCheseaux studies 'Olbers's' paradox 1745 - Laplace proposes Earth is splash of Sun after comet collision 1745 - Bevis makes most detailed staratlas, never published 1746 - Euler explains refraction by wave theory of light 1747 - Clairaut finds first solution of 3-body problem for Moon 1748 - Bradley discovers Earth nutation, predicted by Newton 1748 - Lomonosov discovers conservation of mass & energy 1749 - Dunthorne fixes secular acceleration of Moon 1749 - Melvill builds spectroscope, studies spectrum lines
1750-1759 --------- 1750 - Mayer invents selenographic coordinate system 1750 - Wirgentan finds magnetic disruptions coincide with strong auroral activity 1750 - Michell discovers inverse square law for magnetism 1750 - Mayer designs first lunar globe, never built 1750 - Wright proposes island universes and plurality of worlds 1752 - Melvill studies brightline spectra in flames 1752 - Mayer improves lunar-distance method for finding longitude 1752 - LaCaille issues cluster & nebula catalog of south skies 1754 - Dolland invents heliometer 1754 - Mairan publishes first textbook on aurorae 1754 - Maclaurin posthumously proposes Jupiter is a fluid body 1754 - Kant proposes secular acceleration of Moon motion is due ro Earth slowdown 1754 - Maclaurin papers show gravity of fluid planets 1755 - Kant proposes solar system formed from nebula 1755 - Kant proposes 'Oort cloud' for comet origin 1756 - Cantor discovers first disruptions in geomagnetic field 1756 - Lomonosov argues for wave nature of light 1757 - Dolland perfects achromatic refractor 1757 - Campbell, and Bird, invents marine sextant 1757 - Clairaut fixes best ever mass of Moon and planets 1758 - Palitzsch finds Halley's comet, first comet whose future return path was predicted 1758 - Halley's comet returns, first periodic comet 1758 - Messier recovers Crab Nebula, starts catalog of nebulae 1759 - Cantor discovers seasonal shift of geomagnetic field 1759 - Cantor sets up 'C-number' rating for geomagnetism
1760-1769 --------- 1760 - Lambert studies diffuse reflection, invents 'albedo' 1760 - Lambert makes first photometry of planet albedo 1768 - Euler proposes aether to carry light waves 1761 - Lambert proposes Milky Way is heaps of star clusters confined within a disc 1761 - Lomonosov discovers atmosphere of Venus during transit 1761 - Maskelyne perfects lunar-distance method for longitude 1761 - Harrison invents sea-worthy clock for longitude 1761 - 1st of 18th century Venus transits 1761 - Lambert calculates transfer trajectories between planets 1764 - Lagrange explains lunar librations 1765 - Euler predicts Chandler motion of Earth poles 1765 - Winthrop makes first calculation of comet's mass 1766 - Titius explains gap in planet orbits, now 'asteroid belt' 1767 - Michell proposes binary star systems 1767 - Michell assesses Vega is ~460,000 AU (~7.2 LY) away 1767 - Maskelyne begins publishing 'Nautical almanac and astronomical ephemeris' 1767 - Rittenhouse invents clock-driven model of solar system 1769 - 2nd of 18th century Venus transits
1770-1779 --------- 1770 - Messier discovers comet Lexell, notes it as Earth threat 1772 - Messier issues 1st part of cluster & nebula catalog 1772 - Bode issues Titius-Bode relation of planet orbits 1772 - Lagrange discovers libration points in gravity field 1773 - Herschel starts study of proper motions of 13 stars 1773 - Capt Cook 1st European to observe aurora australis 1774 - Wilson discovers depression of sunspots below photosphere 1774 - Herschel builds own first telescope 1774 - Maskelyne measures gravity pull of nearby mountain 1775 - Mayer issues first topograohic map of Moon 1776 - Lexell, also Prosperin, calculate ellipse orbit for Lexell's comet, first short-period comet 1776 - Lexell discovers 1767 Jupiter interaction with comet Lexell 1777 - Mudge invents remelt process for metal mirrors 1777 - Mudge perfects zonal test of parabolic mirrors 1778 - Herschel begins Jupitter studies, discovers three large 'SL9' spots 1778 - Franklin explains atmospheric circulation among climata 1778 - Franklin explains aurora as electrical discharges 1779 - Olbers invents new method to calculate comet orbits 1779 - Herschel invents filar micrometer 1779 - Darquier explains planetary nebulae 1779 - Lexell studies 1779 Jupiter-comet Lexell interacton, shows comet mass less than 1/9,000 of Earth.
1780-1789 --------- 1780 - Williams rediscovers 'Baily's beads' in solar eclipse 1780 - Herschel discovers 'Encke's division' in Saturn B ring 1781 - Herschel discovers Uranus, first new planet since antiquity 1781 - Herschel shows Earth-Mars similarity of seasons 1781 - Herschel questions Earth as stable clock. based on Jupiter's variable rotation. 1781 - Lexell, also Olbers, shows Uranus has a planet, not comet, orbit 1781 - Maskelyne & Herschel stage telescope rally; Herschel wins 1781 - Messier discovers cluster of nebulae, Virgo galaxy cluster 1782 - Herschel discovers real binary stars, first is Castor 1782 - Goodricke discovers beta Persei & delta Cephei as variables 1782 - Goodricke proposes eclipsing binary stars 1782 - Herschel discovers Sun's motion thru local stars 1783 - Mechain shows many new nebulae in Virgo cluster, but apparently never documented them 1783 - Michell proposes blackholes 1784 - Pigott discovers delta Cephei as variable 1785 - Hutton proposes Earth is several million years old 1785 - Herschel discovers millstone shape of Milky Way 1785 - vonZach searches for planet in Titius-Bode gap, gives up with no finds by 1800 1785 - Schroeter discovers clouds on Mars 1785 - Laplace develops field description for gravity 1786 - Herschel publishes best catalog of nebulae & clusters, becomes by late 19th 'New General Catalog' 1786 - Gilpin begins regular records of geomagnetic field 1787 - Laplace proposes Saturn has very many nested solid rings 1787 - Herschel discovers Uranus moons Titania & Oberon 1789 - Schroeter discovers solar photosphere granulation 1789 - Herschel builds 'Herschel' scope with 1.2m mirror 1789 - Russell builds first globe of Moon 1789 - Herschel discovers Saturn moons Mimas & Enceladus 1789 - Herschel measures Saturn ring thickness, ~500Km 1789 - Herschel discovers oblateness of Saturn 1789 - Herschel explains globular clusters 1789 - Herschel proposes Saturn has only two solid rings separated by Cassini's division
1790-1799 --------- 1790 - Michell builds first 'Cavendish' machine, never used 1791 - Banneker improves calculation of eclipses and Moon phases 1791 - Schroeter discovers lunar rimae (rilles) 1792 - Schroeter measures Venus atmosphere, about 14Km thick 1792 - Delambre & Mechain fix size of Earth, define the 'meter' 1794 - Chladni proposes meteors fall from outer space 1795 - Bowditch issues 'American practical navigator' 1795 - France adopts metric system of measures 1795 - Pigott discovers R Coronae and R Scuti as variables 1796 - Laplace improves nebular origin of solar system 1797 - Olbers develops 'Olbers's' method of orbit calculation 1797 - Cavendish fixes Earth density by measuring Newton constant 1798 - Laplace, also Lagrange, shows stability of solar system 1798 - Laplace proposes blackholes 1798 - Brandes starts triangulation measures of meteors 1799 - Herschel measures rotation of Saturn ring, 10h 43m 1799 - vonHumboldt starts geomagnetic mapping of Atlantic OCean 1799 - vonHumboldt makes first detailed study of Leonid meteors 1799 - Brandes & Brenzenberg show Leonids are ~97Km above ground 1799 - Herschel disocvers infrared radiation in sun spectrum