“A WARNING FROM MARS”. Climate risk assessment in the Museo della Specola

Museum microclimate plays a key role in the conservation of scientific instruments on display. Finding appropriate values of temperature and relative humidity to guarantee the entire collections safeguard is a difficult task. Each object responses peculiarly to the environment depending on its composition, conservative history, and adaptations to the environment variability over years. Sometimes, the different materials coexisting in a scientific instrument may develop pathologies not yet fully known. The question becomes even more challenging if one considers that microclimate management is not easy, especially in buildings not originally designed for conservation purposes.The Museo della Specola in Palermo has recently face these critical issues. The museum is in the ancient Observatory, built in 1790, on the top of the 12ndcentury Royal Palace. Although efforts have been made to protect the collection over the years, there is still much to be done. An exhibited object had clearly evidenced that the environmental conditions need to be urgently improved. It is a 19th-century painted wooden globe reproducing the surface of Mars: in less than two years, damages of its pictorial layers occurred at a slow but progressive rate. Conservation measures have been adopted to stop the serious deteriorating processes, but the risk of further deterioration phenomena involving other objects is expected to increase substantially if no actions are taken. This contribution intends to present the results of the preliminary study concerning the thermo-hygrometric records taken in the museum over recent years to control the environmental conditions and assess if the collection is exposed to microclimate risks. Specific actions to improve climate conditions will be proposed.