The Sun in the ChurchBetween 1650 and 1750, four Catholic churches were the best solar observatories in the world. Built to fix an unquestionable date for Easter, they also housed instruments that threw light on the disputed geometry of the solar system, and so, within sight of the altar, subverted Church doctrine about the order of the universe. A tale of politically canny astronomers and cardinals with a taste for mathematics, The Sun in the Church tells how these