Bianchini's tables in Copernicus's own hand.

A copy of planetary-latitude tables circulated by Giovanni Bianchini survives in Copernicus's handwriting. Follow what that artifact establishes, what it only suggests, and what the almanacs argue against.

Guide by ChronologiaOS editorial guides

4 min read · Published 2026-10-10

Start with the artifact

Chabás and Goldstein's study of planetary-latitude tables connects Ptolemy, Giovanni Bianchini, and Copernicus. The research case rates it strong evidence, at 98 out of 100, that a copy of Bianchini's planetary-latitude tables survives in Copernicus's hand. A surviving copy makes the lineage testable at the level of individual tables and parameters. Archive for History of Exact Sciences ↗

Where the tables came from

Rosińska's study of the Uppsala notebook finds that the latitude tables Copernicus entered there go back to the Italian fourteenth century. Bianchini commented on and circulated them but did not author them; the original version is tied to Giovanni Dondi of Padua, and the study's English summary says Dondi's tables rest not on Ptolemy's but on those of al-Battani, known through a Latin translation of his Opus astronomicum. The research case grades the whole lineage a plausible hypothesis, at 76, and insists it be scored link by link, not as one verdict. Copernicana, vol. 1, no. 2 (Nicolaus Copernicus University digital library) ↗

When did he copy them?

Goddu summarizes Rosińska's dating of the latitude-table work to Copernicus's Cracow period. The research case rates that dating as strong evidence but modest, at 86, and phrases it with 'may': it is a dating argument, not a colophon. Journal for the History of Astronomy ↗

What the almanacs argue against

Dobrzycki and Kremer found that all extant Regiomontanus almanacs they examined are strictly Alfonsine, and that Peurbach and Regiomontanus used Bianchini's tables while testing Alfonsine predictions against observation. The research case draws the consequence at 97: Copernicus owning and annotating Regiomontanus's tables does not establish Maragha ancestry for those tables. Journal for the History of Astronomy ↗

A question to carry forward

Ownership, copying, and use are three different acts. Which of the three does a surviving annotated table actually document, and what would you look for in the margins to tell them apart?