In 1918 the only Mexican institution dedicated professionally to astronomical work was the National Astronomical Observatory, which had begun operations in 1878. In that year of the 20th century, Mexico was immersed in the armed movement known as the Mexican Revolution, which strongly affected the social and economic structure of the country. The Mexican astronomers saw their group drastically reduced and their infrastructure limited; however, they made great efforts to continue their participation in the international project of the Carte du Ciel, since they were part of the 18 observatories that originally participated in it. Despite the limitations they suffered, they soon joined the group of seven nations that in 1919 formed the IAU, and two members of that observatory actively participated in the first general assembly held in Rome in May 1922.