Nicolas-Louis de Lacaille
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Abbé Nicolas-Louis de Lacaille, formerly sometimes spelled de la Caille, was a French astronomer and geodesist who named 14 out of the 88 constellations. From 1750 to 1754, he studied the sky at the Cape of Good Hope in present-day South Africa. Lacaille observed over 10,000 stars using a refracting telescope.
Nicolas-Louis de Lacaille
A memorial to the Abbé de Lacaille and Thomas Maclear, at Aurora in the Western Cape of South Africa. The English portion of the inscription reads: "This is the site of the Maclear Beacon positioned in 1838 near the original North Terminal of the Arc of Meridian positioned by Abbé de Lacaille, the first surveyor to introduce Geodetic Surveying into South Africa." Open the image to see the Afrikaans portion.
Leçons elementaires d'astronomie, géométrique et physique, 1755 edition
Messier 55 is a globular cluster discovered in 16 June 1752.
Paris meridian
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The Paris meridian is a meridian line running through the Paris Observatory in Paris, France – now longitude 2°20′14.02500″ East. It was a long-standing rival to the Greenwich meridian as the prime meridian of the world. The "Paris meridian arc" or "French meridian arc" is the name of the meridian arc measured along the Paris meridian.
Meridian Room (or Cassini Room) at the Paris Observatory, 61 avenue de l'Observatoire (14th arrondissement). The Paris meridian is traced on the floor.
The triangulation mesh of the Anglo-French survey 1784–1790
The West Europe-Africa Meridian-arc extending south from the Shetland Islands, through Great Britain, France and Spain to El Aghuat in Algeria, whose parameters were calculated from surveys carried out in the mid to late 19th century. It yielded a value for the equatorial radius of the Earth a = 6 377 935 metres, the ellipticity being assumed as 1/299.15. The radius of curvature of this arc is not uniform, being, in the mean, about 600 metres greater in the northern than in the southern part. The
One of the 135 Arago medallions. This one is located near the Louvre Pyramid.