19th-century Belgian astronomers

Jean-Charles Houzeau de Lehaie (October 7, 1820 – July 12, 1888) was a Belgian astronomer and journalist. A French speaker, he moved to New Orleans after getting in trouble for his politics in Belgium.
In the U.S. he continued his journalistic, astronomical, and political pursuits. He was an abolitionist and joined with unionists in Texas before the American Civil War. In New Orleans he worked with Dr. Louis Charles Roudanez at the newspapers he founded in the 1860s.
Houzeau migrated to Jamaica in the postwar years. After reinstatement from an observatory in Brussels, he returned to Europe to work. He came back to Texas for an astronomical event. He published stirring memoirs and other accounts of his adventures and contacts during his travels, as well as several works on astronomical subjects.

François J. Terby (9 August 1846 – 20 March 1911) was a Belgian astronomer. He had a private observatory at Leuven, Belgium and was an early ardent advocate of the existence of Martian canals.He collected drawings of Mars and wrote the work Aréographie in 1875. He tracked down the Mars drawings of Johann Hieronymus Schröter and deposited them at Leiden University, where they would eventually finally be published in 1881.
A crater on Mars (Terby) is named after him.

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 and towards that end led a Brazilian team in their observations of 1882 Transit of Venus in Punta Arenas, Chile.