Bibliodyssey blog (which recently published a wonderful book about wonderful old books!) has a post up today with scans of a geomantic almanac from the mid-1500s:
The above images come from a manuscript commissioned by Ottheinrich which was completed between 1552 and 1557 (calligraphy by Heinrich Rüdinger and illumination by Albrecht Glockendon [attributed]). It's title is 'Geomantie' (Geomancy) – Codex Palatinus 833 Germanicus. The title is misleading really. This is not a work of geomancy* as any reference material describes it, although there may have been a broader medieval definition which has since been superseded. (…)
The spectacular full page images (…) are all volvelles (rotating paper wheel charts) and were used for various computations such as calculating the time and the lunar phases. The zodiac images on the wheels could be aligned with the night sky and the disk turned to reveal desired incremental measurements. Some were able to function as astrolabes, to give approximate positions of ships at sea.
Link to Bibliodyssey post. And, Amazon link to "BibliOdyssey: Amazing Archival Images from the Internet (Hardcover)," which includes selected works featured on this fine blog over the past years. I have a copy, and it's already dog-eared from too much lovin'.