The Astronomical Observatory of Lisbon, whose cornerstone was laid in 1861, was born from great controversy between Hervé Faye, director of the Observatory of Paris and Christian August Friedrich Peters, astronomer at the Russian Observatory of Pulkovo, on the parallax of the Argelander's Star (1830 Groombridge).

The foundation of Lisbon Observatory

The Astronomical Observatory of Lisbon was founded in 1857 in the sequence of a controversy on stellar parallax measurements involving astronomers from the Observatory of Paris and the Observatory of Pulkovo. The development of this discussion led the contenders to recognize Lisbon as a suitable place to carry out this kind of measurements and to foster the field of stellar astronomy. Some local actors strived to keep up with this wave of international interest and establish a first-rank astronomical institution in the Portuguese capital. In order to fulfil this goal, correspondence was intensively exchanged with leading foreigner astronomers and instrument makers. Besides, a Portuguese Navy officer bound to become the first director of the new institution was commissioned to visit several observatories and instrument workshops abroad, and to spend a few years in Pulkovo as a trainee astronomer. Although founded with generous financial support from the Portuguese crown and lavishly equipped and constructed, the Observatory of Lisbon was later affected by limiting budgets and a shortage of qualified personnel. Nevertheless, local efforts to improve instruments as well as observation and calculation techniques enabled its astronomers to yield important contributions to positional astronomy, especially towards the end of the nineteenth century and the beginnings of the twentieth century. The original instruments and spaces of the Observatory of Lisbon, strongly modelled on those of Pulkovo, are very well preserved, constituting an outstanding extant example of a mid-nineteenth century advanced observatory. The history they embody testifies the connectedness of the astronomical heritage worldwide...

The site chosen for the construction of the Observatory was Tapada da Ajuda, a royal estate over the river Tagus originally used for hunting activities. Among other prospective locations, it was recognised as the site which provided the best conditions of visibility and stability for the instruments. Another aspect, which had been emphasized by Otto Struve, was that the Observatory could be seen from the ships anchored in the river. This was favourable to the transmission of visual time signals. Besides, the scientific monument of Lisbon would appear with its whole majesty to those arriving at Lisbon by the waterfront.

Pedro Raposo : The Material Culture of Nineteenth-Century Astrometry, its Circulation and Heritage at the Astronomical Observatory of Lisbon, ICOMOS

The construction of the Astronomical Observatory of Lisbon (AOL) was due to the strong desire to build a magnificent institution, a reference in Portuguese culture. It was modeled on the foremost observatory of the period, the Observatory of Pulkovo in Russia. In 1992 the AOL became a part of the University of Lisbon, and, in 1995, a unit of the Faculty of Sciences of the same University. Its main building and most of its instruments are generally well preserved and significantly close to their original condition. The AOL was conceived as an observatory dedicated to the advancement of sidereal astronomy, when astrophysics was just emerging and most observatories focused on the study of solar system objects or, at best, on the measurement of stellar positions for cataloging purposes mainly. By 1850, a discussion on stellar parallax measurements between astronomers from the observatories of Paris and Pulkovo led them to realize the geographic suitability of Lisbon for studies in sidereal astronomy and, after a long and complex process of local demarches, the AOL was established with the aim of fostering the knowledge of stellar distances. After the financial support and commitment that King D. Pedro V gave to this project, its construction started on 11 March 1861, under the rule of King D. Luis I, who also contributed to funding the institution, withdrawing money from his personal budget. The first observations were carried out in 1867, but the Statutory Decree establishing the Royal Observatory of Lisbon was approved only in 1878.

The plan of the building, executed by the French architect Jean Colson, who was then the most distinguished foreign architect living in Lisbon, was inspired by the building of the Russian Observatory in Pulkovo. Wilhelm Struve a famous astronomer of the era and director of the Pulkovo observatory, offered his services to the Portuguese government and was considered the main adviser who played a very important role, not only in selecting the equipment, but also in the orientation of astronomer Frederico Augusto Oom, who was given a training stage of 5 years. Oom, who was a lieutenant of the Navy and hydrographic engineer, became the first director of the Royal Astronomical Observatory of Lisbon, had a very important role in the whole foundation of this building. 

A medal that was issued in 1990 at the first centenary of the death of the first director of the observatory. On the obverse the facing portrait of Oom dominates the scene. Legend on the left in five lines is: "ALMI-RANTE FREDE-RICO AUGUSTO OOM", i. e. Admiral Frederico Augusto Oom, in three lines "ENGo HIDRƠGRAFO E ASTRƠNOMO", that is hydrographic engineer and astronomer. On the right are his birth and death year.  Below: "PREMEIRO DIRECTOR DO OBSERVATƠRIO DA AJUDA", i. e. first director of observatory on Ajuda. Below the shoulder of Oom, the signature of the medalist is visible: S. MACHADO.

Lisbon 1  reverseLisbon 1 obverse

On the reverse the building of the observatory is displayed. Legend above is: "NO 1o CENTENÁRIO DO SEU FALECIMENTO", i. e. to the 1st centenary of his death. Below in four lines: "DIA DA MAINHA 8 DE JULHO 1990", that is Navy Day 8 July 1990. Three coats of arms (to be identified) is also visible.