Climate Risk and Conservation Challenges at Palermo’s Specola Museum

The Specola Museum is housed on the premises of the old Palermo Observatory, founded in 1790, and preserves most of the observatory’s cultural heritage. Environmental monitoring following the activation of air conditioning systems in 2018 revealed significant deviations from the historic thermo-hygrometric trends, with particularly dangerous fluctuations in relative humidity. A notable example of the impact of these changes is a 19th-century painted wooden Model of Mars, displayed in the Merz Hall since 2021. In less than two years, the Model has shown progressive damage to its paint layers. Conservation actions have been adopted to stop the deterioration process, but the risk of further deterioration phenomena involving other objects is expected to increase substantially in the absence of intervention. This paper presents the outcomes of a preliminary study on the thermo-hygrometric conditions in the Merz Hall. Based on the European Standard EN 15757: 2010 and the Italian Legislative decree of 10 May 2001, safe ranges for temperature and relative humidity have been identified for the long-term preservation of the collection. These findings will inform future climate management strategies in the museum.