Itinerary edited by the UNIVERSITY OF MODENA AND R. EMILIA 
Observe the sky, from astronomy to meteorology
The idea to endow Modena with an astronomic observatory (Specola) was conceived by the archduke Massimiliano, who in 1814 entered into contact with a young from Modena, Giuseppe Bianchi, a capable scientist who graduated a short time before at the Physics and Mathematics University of Padua. Thanks to Massimiliano intervention, Francesco IV awarded a Scholarship to Bianchi which permitted him to go to Milan to complete his astronomic studies by the Brera Astronomic Observatory. In 1818, the marquis Luigi Rangoni, Studies Magistrate, in accord with University rector Paolo Ruffini appointed him to the chair of Theoretical Astronomy (chair created on purpose for him) and to the charge of Director of the Observatory, which would have been built also in Modena. Already in January, Bianchi sent from Milan to Rangoni a list of the instruments to buy as fundamental for the establishing of an Observatory: a transit instrument for right ascensions, a meridian circle, an achromatic telescope and an equatorial telescope for the extra-meridian observations. On advice of Bianchi, in 1818 Rangoni ordered to the optician Georg von Reichenbach in Munich the meridian circle, which was delivered in Modena in 1823, and to Giovan Battista Amici from Modena (expert optician and scientific instruments builder) the other three instruments.
In 1863, the guidance of the Observatory went to Domenico Ragona from Modena, a big supporter of meteorological studies and prolific writer. In 1865, he projected and built the first meteorological window, improving and making thermometric measurements possible, which till that moment were done on a terrace without any shield. He equipped the observatory of important instruments also thanks to the support of Cantoni, official scientific consultant of the First Official Meteorological Service founded in Italy in 1865, following the initiative of Agriculture Ministry. He built two instruments very important for precision and clarity: hourly pluviometer in 1876, and an evaporimeter around 1870.
The most representative objects of the Collection
Instrument used for determining the equatorial coordinates of the stars through observations made on meridian plane. It was ordered from Este Government in 1818: it was the first real optic instrument of the Observatory, with the use of that, Bianchi started the astronomy and position researches.
The transit instrument consist of a telescope that is able to rotate on a horizontal axis perpendicular to its optic axis and, usually, permanently mounted on East-West direction. This kind of instrument is used together with a clock adjusted on the sidereal Time (of the Moon), and permits to determine the right ascension of a celestial object through the observation and surveying of the exact time of its transit on the meridian. Its structure is similar to the one of the meridian circle; the latter also allowed the measurement of the zenith distance from the celestial object from which its second coordinate, the declination, can be obtained, knowing the latitude of the observation place.
Thanks to this tool several observations of double stars, sun (diameter, eclipses, sunspots), some planets (moreover Saturn) and comets were done.
It is a telescope constructed by Amici basing on the model invented by Isaac Newton (XVII century) and improving later by William Herschel (XVIII century). It is composed of a wood tube at the end of that a metallic mirror of 13 centimeters diameter is mounted. A secondary mirror is indeed placed near the eyepiece, inclined at 45°. Originally, it was equipped with a “comet seeker” and some eyepieces.
The pluviometer was used to measure the year’s amount of rain precipitation and it was installed by Giuseppe Bianchi on his terrace in 1830: here, the funnel was placed, while the amphora was located in the room of meridian instruments. The tank contained up to 20 liters of waters. During the direction of Domenico Ragona (1863-1892) a 24 compartments collector for the hourly rain collection was added to the pluviometer. The pluviometer was used at least 100 years long.
The evaporimeter was a recording invented and built by Ragona; a clock mechanism moved a rotating drum, above it a special graduated chart allowed to record on paper the hourly trend of evaporation. The instrument was placed in cabin, therefore protect from the direct radiation of solar rays. The water evaporated slowly, depending mainly on the relative humidity and temperature.
The Hygrometer allows the measurement of the relative humidity through the calculation of the dew temperature. This instrument is composed of a little silver plate placed on a pedestal and linked to a metallic box: this last was filled with ether in which a thermometer was immersed (today missing). The box was then linked with a tube with a small pump used to make the ether gargle producing in this way a cooling that determined a condensation on the silver plate. The temperature measured in the moment of the record of condensation corresponds to dew temperature.
