In the gardens of the Observatory can be seen a millstone faced building in rather poor condition. It carries the date ; behind it is a sort of large, rusty, metallic hangar. What is it ?
These buildings housed an instrument invented by Maurice Loewy (1833-1907) who was the Director of the Observatory from 1897 until his death. In 1874, Loewy presented to the Council of the Observatory a model of an equatorial instrument with two mirrors ; its purpose was to reduce observing fatigue by enabling the observer to remain immobile. »
The first instrument designed according to this principle was built in 1882 : this was the small equatorial coudé telescope. It has since disappeared ; however, six other instruments of this type were built during the period 1884 to 1892. Two are still in their original state in the Lyon and Algiers observatories ; there is another one in the Nice observatory, but it has been modified.
The largest one was inaugurated in Paris in 1891 in the building which was finished in 1889. It cost 400 000 francs, including the building, which is equivalent to 1,2 million euros : this was the large equatorial coudé telescope.
It was used to take magnificent photographs of the moon and stellar spectra ; it was abandoned in 1939. Most of its parts still exist, but its restoration would require a very significant budget.
