Three Jesuit astronomers and the 16th-century pope who commissioned the Gregorian calendar have recently been honoured with having asteroids named after them.

The new additions include: “562971 Johannhagen,” honouring Austrian Jesuit Father Johann Hagen, who was serving as director of the Georgetown University Observatory when Pope Pius X called him to Rome in 1906 to be the first Jesuit director of the new Vatican Observatory; “551878 Stoeger,” honouring U.S. Jesuit Father Bill Stoeger, a cosmologist and theologian who died in 2014; and “565184 Janusz,” honouring Polish Jesuit Father Robert Janusz, a philosopher and physicist on the staff at the Vatican Observatory.

A working group of the International Astronomical Union also approved of the designation of “560974 Ugoboncompagni,” honouring Ugo Boncompagni, who was elected Pope Gregory XIII in 1572.

The working group approved and published the names in its bulletin on Feb. 7, the Vatican Observatory said in a press release on Feb. 28. There are now 32 asteroids named after Jesuits.

Pope Gregory began the tradition of having papal astronomers and observatories. He commissioned German Jesuit Father Christopher Clavius to help with the reform of the calendar, which took his name, the “Gregorian” calendar, and still today is an internationally accepted civil calendar.

This is not the first asteroid named after a pope, however.

According to the Minor Planet Center’s asteroid orbital database, the “8661 Ratzinger” was named after Cardinal Joseph Ratzinger, the future Pope Benedict XVI, after it was discovered in Germany in 1990.

The asteroid’s discoverer chose to name it after the German theologian, who was head of the Vatican Congregation of the Doctrine of Faith at the time, honouring him as “one of the most authoritative voices in the Vatican.”

“Under his supervision, the Vatican opened its archives in 1998 to enable researchers to investigate judicial errors against Galileo and other medieval scientists,” the centre’s database said.