i propose a revisionist account of the production and reception of galileo's telescopic observations of 1609–10, an account that focuses on the relationship between credit and disclosure. galileo, i argue, acted as though the corroboration of his observations were easy, not difficult. his primary worry was not that some people might reject his claims, but rather that those able to replicate them could too easily proceed to make further discoveries on their own and deprive him of credit. consequently, he tried (...) to slow down potential replicators to prevent them from becoming competitors. he did so by not providing other practitioners access to high-power telescopes and by withholding information about how to build them. this essay looks at the development of galileo's monopoly on early telescopic astronomy to understand how the relationship between disclosure and credit changed as he moved from being an instrument-maker to becoming a discoverer and, eventually, a court philosopher. (shrink)

: Scientific observation is determined by the human sensory system, which generally relies on instruments that serve as mediators between the world and the senses. Instruments came in the shape of Heron's Dioptra, Levi Ben Gerson's Cross-staff, Egnatio Danti's Torqvetto Astronomico, Tycho's Quadrant, Galileo's Geometric Military Compass, or Kepler's Ecliptic Instrument. At the beginning of the seventeenth century, however, it was unclear how an instrument such as the telescope could be employed to acquire new information and expand knowledge about the (...) world. To exploit the telescope as a device for astronomical observations Galileo had to: 1. establish that telescopic images are not optical defects, imperfections in the eye of the observer, or illusions caused by lenses; 2. develop procedures for systematically handling errors that may occur during observation and measurement and methods of processing data. Galileo made it clear that in order to measure and interpret natural phenomena accurately, a suitable method and instrument would need to be developed. It is intriguing, therefore, to regard the Galilean telescope in this light and to discover the linkage established by Galileo among theory, method, and instrument—the telescope. Although the telescope was not invented through science, it is instructive to see how Galileo used optics to employ a theory-laden instrument for bridging the gulf between picture and scientific language, between drawing and reporting physical facts, and between merely sketching the world and actually describing it. (shrink)