Broadening perspectives
Observations of Mars with the Merz-Repsold telescope by one of the greatest astronomers of the Nineteenth century: Giovanni Virginio Schiaparelli
E-ELT
When this telescope will be completed, in 2024, it will be the largest and most sophisticated optical-infra-red telescope in the world. It is called ESO (European Southern Observatory) Extremely Large Telescope. It has a 39-metres-wide mirror and is located on the Chilean Andes at an altitude of 3046 meters. But let us see how the sky was observed in 1875…
The decision to construct the Merz-Repsold telescope
was based on the international wave of success triggered by Giovanni V. Schiaparelli's
martian studies
Beginning in 1877, the scientist's studies of Mars were carried out in Milan, at the Brera Observatory, utilizing a 22 cm Merz telescope. The results he achieved brought him worldwide fame and authority. The Italian scientific community, and the entire country, in general, took pride in this renown. At the end of the 19th century, the newly unified Italy was a nation to be rebuilt entirely: politically, culturally, socially. The echo of Schiaparelli's studies created a "positive visibility" on an international scale. From the government's point of view, fundamental scientific research thus became an indispensable tool for the growth of the new State. Supported by former minister Francesco De Sanctis, a cultured man and personal friend, Schiaparelli obtained the financing needed for the purchase of one of the most powerful refracting telescopes of the era, the Merz-Repsold telescope with which he intended to pursue his studies.
A lucky discovery
Schiaparelli commenced his research on Mars almost by chance. The instruments of the Brera Observatory in 1862 were still those dating from its foundation (1762-1764). In order to carry out his research on binary stars, in 1865 Schiaparelli succeeded in obtaining a new telescope of excellent workmanship, the 22 cm diameter Merz refractor, operational since 1875. To test its abilities, he aimed the device toward Mars: the operation revealed the new instrument's great potential in planetary observation. Thus was born the modern and innovative practice of the study of the surfaces of planets.
Revealing
investments
Thanks to Schiaparelli's influence, on 11 June 1878 the Chamber of Deputies approved the expenditure of 250.000 lire, equivalent to about a million euros today, with 192 votes in favor and 37 against, for the purchase of a new telescope for his Observatory. It would be the largest in all of Italy. The refractor was commissioned of two German companies: Mertz for the optical part and Repsold for the mechanical part. It arrived at the Brera in 1882 and became operational in 1886.
Particolare della struttura di sostegno del telescopio Merz-RepsoldNational Museum of Science and Technology Leonardo Da Vinci
A maximum weight
The Merz-Repsold refracting telescope at the Brera Astronomical Observatory of Milan is equipped with a 49 cm diameter objective lens. In refractors, the objective is composed of systems of lenses that can be more or less complex.
The Merz-Repsold is more than 7 m long, supported by a structure of columns nearly 5 m high.
The tube weighs 3 tonnes, but is perfectly balanced through a system of counterweights. making it possible to adjust its position with very little effort. Even today the instrument is unsurpassed in its typology in Italy.
Telescopes around the world
In those same years, other renowned astronomers were making use of refracting telescopes simliar to the Merz-Repsold. In 1896 Lowell began using the telescope at Flagstaff, Arizona (61 cm diameter, 10 m focal length), while Antoniadi began using the refractor at Meudon in France, (83-cm diameter, 16 m focal length). The largest refractor ever constructed (102 cm diameter, 20 m focal length) has been operating at Yerkes, Wisconsin, since 1897. It remained the world's largest telescope until 1908. when the Mount Wilson reflector came into service. with its 150 cm diameter mirror.
Indispensable
accessories
The Merz-Repsold represents the state of the art for astronomical instruments of its time. At the lower end of the tube, at the focal point of the lens, different instruments are positioned for observations of great precision and various typologies: from direct observation of the stars, to measurement of the distances of separation in multiple stars, to the study of the chemical-physical composition of stars by means of a spectroscope.
Modern times
Along with widespread public lighting, the 20th century brought smog to Milan. The conditions got worse for observing from the Brera, and the Astronomical Observatory was forced to open a branch outside the city, at Merate, near Lecco. Around the end of the 1920s, the most sophisticated instruments were installed here, including the Merz-Repsold. Over time, the discipline evolved and the Merz-Repsold was dedicated to carrying out useful, though routine, observations. Its operational life was terminated at the beginning of the 1960s, when it was removed from its place in the dome.
Restauro del telescopio Merz-RepsoldNational Museum of Science and Technology Leonardo Da Vinci
The restoration
At the end of its operational life, the telescope was dismantled and its parts were put into storage, at the Brera Astronomical Observatory's warehouses in Merate. It was the Brera Observatory, along with the INAF (Italian National Institute of Astrophysics), that promoted the current restoration, involving five years of precision work.
Rimontaggio del telescopio rifrattore Merz-Repsold al Museo della ScienzaNational Museum of Science and Technology Leonardo Da Vinci
A delicate operation commenced in 2010
Each individual part of the instrument was dismantled, cleaned, and rectified. For parts that got lost over time, careful research was carried out regarding similar devices made by the same constructors. The restoration performed involved only the structural and mechanical parts.
Museumization
Italy's principal refracting telescope, an iconic instrument in the history of modern astronomy, is conserved at the Science and Technology Museum in Milan today thanks to an agreement with the Brera Astronomical Observatory and with the National Institute of Astrophysics. To make it possible to include this instrument in the Museum, it was necessary to proceed with a structural reinforcement of the floor, for it to be able to support the total weight, about 7 tonnes. The reassembly of the instrument, restored in the ARASS-Brera laboratories, required some three months.
Mostra del
Museo Nazionale della Scienza e della Tecnologia
Leonardo da Vinci
Via San Vittore 21
Milano
www.museoscienza.org
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