Which Jesuit astronomer disputed Galileo's interpretation of sunspots?

The Jesuit astronomer who disputed Galileo’s interpretation of sunspots was Christoph Scheiner.

Scheiner observed sunspots independently in the early 1610s and described them in letters sent to the Augsburg scholar and banker Mark Welser. Writing under the pseudonym Apelles, he initially argued that the spots could be satellites or other bodies moving near the Sun. Galileo disagreed, maintaining that they were on or very close to the solar surface and were carried around by the Sun’s rotation.

Their exchange became a major episode in the history of early telescopic astronomy. It was not simply a quarrel over priority: the nature of sunspots affected whether the heavens should be regarded as perfect and unchanging. It also intersected with arguments about the Copernican system, the phases of Venus, and the motion of the Sun.

Scheiner later produced extensive solar research in Rosa Ursina, published from 1626 to 1630. The dispute grew personal, especially after Galileo’s 1623 work The Assayer accused Scheiner of taking credit for ideas. Orazio Grassi was another Jesuit involved in a separate Galileo controversy, chiefly concerning comets, not the central sunspot dispute.