PETER Catt, the dean of St John's Cathedral, had a confession to make this week. "When I was younger I was a very good atheist," he said.

His parents, both school teachers, were non-believers.

"I wasn't brought up with no religious culture at all," he said.

"I went to Sunday school for four weeks, that was all. A neighbour took me.

"But my family never went to church."

He first saw God down a microscope while studying to be a microbiologist.

At the time the Very Reverend Dr Peter Catt was completing his PhD into the activities of bacteria which thrive on the root systems of wattle trees.

"Science taught me all about religion and brought me closer to God," he explained.

"Studying that helped me develop a sense of awe.

"I still maintain a real interest in how science and religion bounce off each other."

So he is proud of the cathedral's new stained-glass panels by artist Glenn Mack.

They depict Christian religious symbols interwoven with the ever-expanding universe taken by the hubble telescope.

"The windows are in sync with who I am and who I want to be," said Dr Catt, the father of three children aged 17 to 22.

Then there is a grape vine and a serpent entwined on the double helix of DNA, symbols of money and mankind and words from the gospel of St John juxtaposed with Pythagoras' Theorem and Einstein's theory of relativity.

There is a mandala (the Sanskrit term for circle) bearing the names of the divine of other faiths.

"The Christian symbols remind us of the need to stand firmly with one's own tradition if one is to enter into discussion with others," Dr Catt said.

And next Tuesday St John's enters its post-building phase with the launch of its ambassadors program at 6pm by patron and High Court judge, Justice Susan Kiefel.

"The idea of the ambassador program is to promote the building and its good use."

Ambassadors need not be Anglicans, Dr Catt said. Lovers of architecture, and the visual and performing arts gather at St John's even if they are from different faiths.

There will be art exhibitions and musical performances by groups like Camerata.

Originally published as Science converts ex-atheist