This work, originally published in 1992, addresses the ancient and widely held view that Ptolemy was an inferior practical astronomer who manipulated the observations to fit his models. Examining the solar and lunar observations found in Almagest and the parameters of the models ostensibly derived from them, it finds scant evidence to support this view. Ptolemy’s lunar observations are no less accurate than those of his predecessors, and the individual errors of the lunar observations are as a whole consistent with what we would expect from naked eye observations. The parameters derived from these observations, moreover, are in every instance more accurate than we would expect given the errors of the observations. Thus, it appears that Ptolemy had more observations at his disposal than he reports, and that he was more skilled than has been recognized at deriving accurate parameters from them.

1. networked interpretation
2. Ptolemy
3. sociology of the history of science

Original publication: Britton, John P. Models and Precision: The Quality of Ptolemy’s Observations and Parameters. Interpretatio Series B. 2020. URI: https://ircps.org/interpretatio-b/b001/. This material has been re-published in an unmodified form on the Canadian HSS Commons with the permission of Iter Canada. Copyright © the author(s). Their work is distributed by Interpretatio under a Creative Commons Attribution-NonCommercial 4.0 International License. For details, see https://creativecommons.org/licenses/.