[citation needed] In 1987, Genevieve Soucail of the Toulouse Observatory and her collaborators presented data of a blue ring-like structure in Abell 370 and proposed a gravitational lensing interpretation[2] In the 1990s the observatory worked on MEGACAM with several other institutions.

He published Recueil d'exercices sur le calcul infinitesimal as well as making several expeditions, including an 1874 trip to Japan.

Henri Joseph Anastase Perrotin was Tisserand's assistant astronomer, and they both went to the Paris Observatory in 1878.

[5] Launch instruments at the observatory included two refractors and 28 inch quadrant, and one clock.

[12] This included a transit instrument by Lennel dating to 1774, Dollond telescope, and several quadrants.

[12] The observatory participated in the Carte Du Ciel project, recording over a thousand plates (i.e. astronomical photographs) between 1887 and 1939.