Giovanni Battista Hodierna

Lore & Background

Hodierna was born in Ragusa, Sicily and died in Palma di Montechiaro. While serving as a Roman Catholic priest in Ragusa, he also practised astronomy. In 1654 he published a book entitled De systemate orbis cometici, deque admirandis coeli characteribus that contained a catalogue of celestial objects and a list of double stars. The work anticipated Messier's catalogue and the double star catalogues by Christian Mayer and William Herschel, but had little impact; Messier seems not to have known of it.

Hodierna was prolific in publication, and his interests spanned many disciplines. In addition to his astronomical observations, he utilized optic microscopes to study insects, publishing on the multifaceted eye of flies and that in bee colonies only the queen is oviparous. His other works include Archimede redivivo colla stadera del momento, Protei cælestis vertigines seu Saturni systema, and La stella nuova e peregrina comparsa l'anno 1600 sul petto del cigno.

Reader's Guide

Giovanni Battista Hodierna's significance lies in his early astronomical catalogue, which predated and anticipated the more famous Messier catalogue. His 1654 work, De systemate orbis cometici, listed some 40 celestial objects, including at least 19 real nebulous objects that could be mistaken for comets. This catalogue, along with his list of double stars, foreshadowed later systematic surveys by Charles Messier, Christian Mayer, and William Herschel. However, his work had little contemporary impact, and Messier appears to have been unaware of it. Hodierna's legacy is thus that of a largely overlooked pioneer whose observations were rediscovered by later historians. Beyond astronomy, his use of microscopes to study insect anatomy, such as the multifaceted eye of flies and the oviparous nature of the queen bee, demonstrates his broad scientific curiosity. His career as a priest-astronomer places him within the tradition of Roman Catholic scientist-clerics, though his contributions remained obscure for centuries.

Did You Know?

• Hodierna's catalogue of celestial objects contained some 40 entries, including at least 19 real and verifiable nebulous objects.
• His 1654 book anticipated Messier's catalogue and the double star catalogues by Christian Mayer and William Herschel.
• He used optic microscopes to study insects, publishing on the multifaceted eye of flies and that only the queen bee is oviparous.
• Hodierna served as a Roman Catholic priest in Ragusa while practising astronomy.