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.