Daniel O'Connell

Daniel Joseph Kelly O'Connell was a seismologist, astronomer and Jesuit priest who is particularly known for his work in observational astronomy. He worked primarily observing binary star systems, and was involved in photographing the Green Flash. He was also the third president of the Pontifical Academy of Sciences. He later joined the society in 1913, which he was a part of for the rest of his life. This paper lead to the O'Connell effect being named after him, although it does not yet have a physical explanation.

The next year, O'Connell left Australia, as he was appointed the director of the Vatican Observatory in Rome. He organized two study weeks for the Pontifical Academy, one on Stellar Populations, and another on Nuclei of Galaxies in 1957 and 1970 respectively; he edited the proceedings of each into books. When Pope Pius XII was criticised for speaking in the second study week, O'Connell defended him, saying that the Pope "studied very carefully the technical material presented to him and made it his own, and moulded it so as to drive home the religious or ethical considerations he wished to put before his audience."