Giovanni Hodierna was a 17th-century Italian astronomer and mathematician, born in 1597 in Sicily. He is best known for his work in observational astronomy and for his contributions to the study of comets. Hodierna created detailed star catalogs and was one of the early proponents of using telescopes for astronomical observations. In addition to his astronomical work, Hodierna was also involved in the study of optics and the design of telescopes. His writings influenced later astronomers, and he is remembered for his efforts to improve the understanding of celestial phenomena during the Baroque period.