La polemica sul telescopio con gli “occhi” del Saggiatore

The essay analyses the controversy between Galileo and the Jesuit Orazio Grassi concerning the telescope's limited magnification of comets. It compares Grassi's thesis, according to which this was due to the distance of the celestial body from the observer, with Galileo's, who instead argued that the cause of the different magnification lay in the irradiation that characterises observation with the naked eye as opposed to telescopic observation.