Coordinated on a global scale, collective observation of the Mercury transit of 1753 and the Venus transits of 1761 and 1769 exemplify Enlightenment confidence in a spatially and socially extended "big science," one capable, in principle, of transcending difference at many levels: national and confessional, institutional and personal, theoretical and practical. Such instances of observational collaboration reflect on a grand level what had become ordinary for working astronomers. Sufficient predictive accuracy, rising concern for precision measurement, and the development of new institutional forms of support had made plausible the repeated observation of astronomical events as temporally dispersed as Venus' transit across the face of the sun or as quotidian as the sun's meridian passage. At the same time, early modern astronomers also looked beyond the temporal and geographical bounds of the contemporary Republic of Letters to textual material they inherited from classical antiquity, drew from medieval chronicles, or sought through diplomatic, merchant, and missionary networks wrapped around the early modern globe. In their quest for data, astronomers built epistolary connections and banked on conventions of intellectual sociability, circulated instructions via script and print and provided recording templates. They tabulated and interpolated, collated and conjectured as they made common cause with other learned communities, deploying techniques for data construction, collection, and adjudication brought to the fore in recent scholarly work on the global dimensions of Newton's Principia and the Dutch East India Company's natural historical interests, the complexities of managing information in the age of print and of assessing discrepant measurements in the context of the new science, and the emergence of observation as both scientific genre and epistemic category. With particular attention to sinological materials as a limit case, this project approaches the early modern European efflorescence in astronomical data gathering through the often conflicting forms of archival reasoning that underwrote material collections resulting from this global activity.