On Sunday, 9 August 2015 17:57:57 UTC-4, Brian Denzer wrote:
In the posthumously-published 18th century manuscript, Descriptio Automati Planetarii, Christian Huygens described the motions of the planets in degrees traveled in one Earth year.

So, for example, he said that Earth travels 359° 45' 40" 31''' in one year, but Saturn travels just 12° 13' 34" 18''' in one year.

What is he talking about, how did he arrive at those numbers, and what is the unit used in the last term (thirds?)?

The degrees traveled by other planets are also listed, but the document is in Latin, so it's very difficult to extract those ratios.

I rather like his approach as an exercise in the math of astronomy. I'd like to understand it better.

Descriptio Automati Planetarii:

https://play.google.com/books/reader...n&pg=GBS.PA139

The reference to degrees traveled by Earth and Saturn:

https://play.google.com/books/reader...n&pg=GBS.PA174

Thanks for any assistance that might be offered.

Kind regards,
Brian

Find the "year time" of each planet, the time it takes to orbit the sun, and divide to get degrees.
Mars with an almost 700 Earth day orbit would go 192 degrees in an Earth year.