[3] It has gone by a variety of names having to do with various aspects of the telescope, such as its aperture, or location on the East tower of the Paris observatory, or its equatorial mount made by Brunner.

[4] The telescope is known to have been used for observing double stars, minor planets (asteroids), and also some photographic astronomy in the late 19th century.

[4] When it made its debut in the late 1850s, it was noted for its 38 cm (15 inch) Lerebours objective, Brunner mount, and there was some discussion over its use for astro photography.

[10] This telescope is noted for its photometric observations of the Galilean Satellites (Io, Europa, Callisto, and Ganymede) in the 1880s.

[5] On June 23, 1878 the East Equatorial of Paris Observatory (the Arago) was first used for photometric detection of an eclipse of Jupiter's moons.

[12] The telescope was also used to photometrically study double stars with Photometer H.[12] A Nicol prism was used at the eyepiece for certain instrumentation setups.