The Astronomical Compendium is a collection of small tools for mathematical calculations in a single case. He provided the user with many options in a ready-made format.
It was not a cheap set and obviously indicated wealth. owner. The photo shows an astronomical compendium, circa 1550 gg., Augsburg, gilding, brass.
The compendium included a passage instrument for determining time of night by stars, list of latitudes, magnetic compass, list ports and harbours, a perpetual calendar and a lunar indicator. compendium could be used to determine time, tide height in ports, and calendar calculations.