Luíz Cruls or Luís Cruls or Louis Ferdinand Cruls (21 January 1848 – 21 June 1908) was a Belgian-Brazilian astronomer and geodesist. He was Director of the Brazilian National Observatory from 1881 to 1908, led the commission charged with the survey and selection of a future site for the capital of Brazil in the Central Plateau, and was co-discoverer of the Great Comet of 1882. Cruls was also an active proponent of efforts to accurately measure solar parallax

Early life

Cruls was born in 1848 in Diest, Belgium, the son of Philippe Augustin Guillaume Cruls (a civil engineer) and Anne Elizabeth Jordens. From 1863 to 1868, Cruls studied civil engineering at the University of Ghent. In 1869 he undertook training as a military engineer and officer, graduating as a 2nd Lieutenant. Cruls served in the Belgian army, attaining the rank of 1st Lieutenant, until 1873 or 1874 (sources disagree).

Likely inspired by Brazilian friends at University (including Caetano de Almeida Furquim, a fellow engineer), Cruls resigned his commission and set out for Brazil on 5 September 1874.

Brazil, Belgium, and back again

Within weeks after Cruls's arrival in Brazil, Joaquim Nabuco and his father arranged for him to be presented to Dom Pedro II, Emperor of Brazil, and more importantly, to meet Buarque de Macedo, the Director General of the Ministry of Public Works.

In January 1875 Cruls was forced to return to Belgium for family reasons. The Commission took Cruls's unexpected return as an opportunity, and assigned him the duty of assisting the Brazilian ambassador in coordinating the receipt and transportation of geodesic instruments that the Commission had previously purchased. Crul's monograph analyzed the various methods then used to fix geographic points via triangulation. This work won Cruls the respect of Emmanuel Liais, director of the Imperial Observatory in Rio de Janeiro, who would later hire him in 1877. Cruls returned to Brazil in June 1875

Imperial Observatory

In December 1877, Emmanuel Liais appointed Cruls to the Commission on Longitude, a position at the Imperial Observatory. a monograph on his observations of the surface features and rotation of Mars during its 1877 opposition. was Cruls's first scientific paper to be published in the Comptes Rendus of the French Academy of Sciences, and provided estimates the diameters of the Sun and Mercury. and Spectroscopic Research on Some Unstudied Stars, both articles appearing in the same issue of Comptes Rendus.

Cruls would go on to publish a total thirty-five papers, monographs, and books on astronomy in his lifetime; In 1879, Cruls was promoted to Assistant Astronomer, based both on his work at the Observatory and the high regard Liais had for Cruls's scientific capabilities. Cruls took this opportunity to formally change his first name to "Luíz", the Brazilian form of "Louis" or "Luís".

1882: Cruls's annus mirabilis

thumb|The Great Comet of 1882In his Biographical Encyclopedia of Astronomers, Thomas Hockey cites 1882 as Cruls's annus mirabilis.

Legacy

In its obituary for Cruls, Nature cited Cruls's observations of the 1882 Transit of Venus at Punta Arenas as one of his most important achievements in astronomy. The Cruls Islands in the southern Wilhelm Archipelago off the coast of the Antarctic Peninsula are also named for him, as is Refuge Astronomer Cruls, a Brazilian Antarctic summer base. Cruls was also honored on a Brazilian postage stamp in 1992 celebrating the centennial of the Cruls Commission.

Asteroid 29298 Cruls is named after him.

See also

References

  • Obituary from Astronomische Nachrichten
  • Luiz Cruls Cartoon Biography