===== Directors Leiden Observatory and landmarks =====
^Jaar   ^ Naam ^ Remark ^
|17 juli 1575  |Gerard Bont| mathematics, medicine|
|1 okt 1587    |Rudolph Snel v. Royen sr.|
|1609-1626    |Willebrord Snel v. Royen jr. (Snellius)|triangulation Netherlands|
|1629-1667    |**Jacob Gool**| +night assistent; teaching, popularisation|
|1633/1634    | |**Observation platform on Academy: \\ start of the observatory **|
|1638 |Georg Markgraf|Establishes first European-style observatory in the America's in Recife|
|1654| Huijgens|observes Saturn|
|1668-1682|**Christiaan Melder**|mathematics|
|1682-1705|**Buchardus de Volder**|acquires lenses, mirror, clocks, sextant|
|1705-1708|**Lutharius Zumbach de Croesveld** |a.i. leaves for Kassel|
|1708-1717  |  |brother Mussenbroek maintains instruments|
|1710 | |gift Sphaera planetarium|
|Up to this time \\ there are no telescopes \\ present in the observatory.|
|1717-1742    |**Willem Jacob ’s Gravensande** |physics + explicitly astronomy|
| 1734 | |reflector Hearnes, pass. instr. Sisson, heliostaat.|
|1740 | |meridian transit circle|
|  | |Ass. La Bordes, Petrus van Mussenbroek, physics|
|1742-1769     |**Johan Lulofs**|{{:history:venus_overgang_1761_lulofs.jpg?linkonly|}}|
|1763 |**J.A. Fas** |lector tot 1817, sometimes a.i.|
|1769-(1805)   |**Dyonisius v.d. Wijnpersse**|
|1793-1794      |**Pieter Nieuwland**|
|1799-1805      |**Frederik v. Beeck Calkoen**| leaves for Utrecht|
|1811-1826      |**C. Ekama**| from the closed Franeker University|
|1823 | |reflector Roelof&Rienks|
|1826-1837     |**P.J. Uylenbroek**| physics|
|1837-1861     |**F. Kaiser**|
|1835 | |comet of Halley|
|1837 | |director, acquires 6”, transit telescope, universal instrument, clocks|
|1853-1856 |J.A.C. Oudemans| assistant Kaiser|
|1857 |Kaiser becomes Rector Magnificus |Verficatie Rijks Zee-Instrumenten (now MEOB) |
|1859 | |National Time Service|
|1861 | |**Opening of new Sterrewacht**\\  (transit circle, 18 cm refractor)|
|1872 |**W. Valentiner a.i.**|
|1872-1908|**H.G. v.d. Sande Bakhuyzen**|
|1883 | |Verificatie leaves Sterrewacht building|
|1874 | |heliometer 8½ cm for Reunion, 1893/98 Zenith telescope|
|1878 | |Heliometer building|
|1885 | |10”|
|1898 | |astrograph (Fotograaf)|
|1898 | |zenithtelescoop (Talcott)|
|1908-1918    |**E. F. v.d. Sande Bakhuyzen**|
|1918-1934    |**W.de Sitter**| Student of Kapteyn {{:history:een_beknopte_geschiedenis_van_het_kapteyn_instituut.pdf|Astrononmical Institute Groningen}}|
| | |Fotograaf used for photometry|
|1924 | |renovation, addition of small domes East and West|
|1923 | |contract  Unie Sterrewag S.A., Franklin Adams telescope|
|1930 | |Boerhaave museum|
|1935-1945    |**E. Hertzsprung**|
|1938/50 | |Rockefeller telescope S.A.|
|1938 | |Fotograaf used for astrometry|
|1945-1970    |**J. Oort**|
| 1958 | |Light Collector (90 cm refractor) Hartebeestpoortdam S.A.|
| 1962 |ESO established (Chili)||ESO had more than half time a Leiden director: \\ 1970 Blaauw, 1975 Woltjer, 1988 vd Laan, 2007 de Zeeuw|
|1964 |ESRO established|
|1979 |La Palma, Isaac Newton telescope Canary Islands|
|1975 |ESA established (absorbed ESRO)|