Researchers from the Sorbonne and New York Universities discovered a lost manuscript of Ptolemy describing the design and the use of the Meteoroscope:

Ptolemy’s Meteoroscope was a tool to calculate heights and distances, often in relation to celestial bodies. It is referenced in several ancient texts, including Ptolemy’s own book on mapmaking, the Geography. However, details of its structure and operation were lacking, until now.

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You could then use it for numerous applications such as determining your latitude in degrees from the equator, the exact date of a solstice or equinox, or the apparent location of a planet in the zodiac.