retro agor

Harum quinque stellarum quae se ingerunt nobis, quae alio atque alio occurrentes loco curiosos nos esse cogunt, qui matutini vespertinique ortus sint, quae stationes, quando in rectum ferantur, quare agantur retro, modo coepimus scire;

‘The five planets force themselves upon our attention. Occurring in one place or another they compel us to be curious. Recently we have begun to understand what their morning and evening risings mean, their positions, the time of their movement straight forwards, why they move backward.’