UNC astronomer helps cathedral plot Easter morning stars
Posted July 26
Updated July 27
Raleigh, N.C. — A University of North Carolina at Chapel Hill professor played a key role in designing an aspect of the Holy Name of Jesus Cathedral in Raleigh that is in plain view but the significance of which is more subtle.
The canopy over the crucifix hanging behind the cathedral's altar, known as a baldacchino, is a common feature in major churches to show authority. The most famous baldacchino hangs over the altar of St. Peter's Basilica in Rome.
For Raleigh's cathedral, church officials wanted a pattern of stars on the canopy.
"They wanted the stars to depict an accurate date," said Chris Clemens, a professor of physics and astronomy at UNC-Chapel Hill.
The date in question was a Sunday in April in year 33 – Jesus' resurrection on the first Easter.
When longtime friend Father James Labosky, parochial vicar at St. Thomas More Catholic Church in Chapel Hill, asked Clemens to help, his first first reaction was apprehension.
"I hope they know the date they want," he recalled thinking. "I’m not going to wade into the problem of when this happened because that’s a question solved by calmer and wiser minds than mine."
But Clemens agreed to take on the project.
"It was a simple matter of what did the sky look like in April in Jerusalem," he said.
Using special software to "turn off the air" and remove the blue sky, he was able to view the sun, the stars and the planets Venus, Saturn and Jupiter clearly.
"Stars don’t move quickly with respect to one another. Their position in the sky is the same season to season, changing really, really slowly," he said. "There are three planets amongst the stars, and that pattern is unique to that day. That doesn't ever really repeat where those planets are with respect to the sun."
The star pattern does include one minor deviation, however. The baldacchino includes a sprinkler head, and Raleigh's fire codes prevented it from being painted over.
A lifelong Catholic, Clemens said was honored to do some work on the cathedral, allowing his faith to blend with his study of science.
"I don't see a conflict between being an astronomer and being a Catholic," he said, noting Jesuits studied astronomy for centuries. "In fact, it's the other way around."