(ProQuest: ... denotes non-USASCII text omitted.)In a recent review, Raymond Mercier raises in passing an issue that deserves to be highlighted, namely the difficulties created for modern historians by the lack of an adequate complete edition and translation of one of the principal documents of later Greek astronomy, Theon of Alexandria's commentary on Ptolemy's Almagest.1 For the first four books we have the exemplary critical edition (lightly annotated but regrettably without translation) by Adolphe Rome,2 but Rome did not live to finish the project, and we may have to wait a long time for someone with the requisite competence and stamina to take up where he left off. In the meantime the only printed text for a large part of the commentary is the cumbersome 1538 Basel edition,3 which was based on a single, not particularly authoritative manuscript (Nurnberg Stadtbibliothek Cent. V, App. 8, formerly owned by Regiomontanus), and again lacks a translation so that it is effectively inaccessible to many modern researchers. The present note makes an extremely modest and provisional contribution to rectifying this situation by offering a more reliable text and translation of a mere sentence, comprising Theon's observation report of the solar eclipse of A.D. 364 June 16.4I give the passage as it appears on f. 242r of the ninth-century Laur. plut. 28.18, which is by a wide margin the oldest, and in Rome's judgement the most accurate, manuscript of the first six books of Theon's commentary:5...And moreover we observed most securely the time of the beginning of the immersion, with respect to seasonal and apparent time, 2 1/2 1/3 hours after noon, and the (time) of the middle of the eclipse 3 1/2 1/4 1/20 hours after (noon), and the (time) of the end of the clearing approximately 4 1/2 hours after noon of the aforesaid 22nd of Payni.The 1538 edition has a couple of variants immaterial for the meaning, and one significant one where instead of ... (fraction, qualifying the preceding numerals) before the first instance of ... (hours), it has ... (equinoctial hours). In an article on Theon's calculation of the circumstances of the eclipse Rome writes about the observation report at some length, pointing out that the unpublished version in Laur. plut. 28. 1 8 was undoubtedly correct in not having the word 'equinoctial' , so that the observed times are expressed in seasonal hours after noon, resolving a conflict that Fotheringham had found between modern theory and Theon's times on the supposition that they were in equinoctial hours.6 (Times in seasonal hours were more commonly counted from sunrise or sunset.) It is worth noting that the reported time of mid-eclipse is not simply the moment halfway between the beginning and end of obscuration, so Theon appears to have attempted to determine the point when the obscuration was at its maximum.7[Reference]REFERENCES1. JHA, xlii (2011), 405-8.2. A. Rome, Commentaires de Pappus et de Theon d'Alexandrie sur l'Almageste, ? …