Hyginus goal, as stated in his work was to explain more clearly the facts of which Aratus spoke in a confusing manner, so that it appear that we take much care in what we have engaged with. And if thanks to the use of the best authorities so that nobody have treated [the same topic] with more brevity or trustfulness... That is why we decided to use the most important works... For we wrote about the most important topics for the use/ benefit of our friends the most erudite people; dealing with no trifling things, we strive to obtain/ win the esteem of the readers.
The work is divided in four books:
- Book I: introduction to cosmology, celestial sphere, celestial and terrestrial circles.
- Book II: catasterisms, on the mythological stories of the 42 constellations, the five planets and the Milky way. Rationale: horum omnium non inutile videtur historias proponere, quae certe aut utilitatem ad scientiam, aut iucunditatem ad delectationem adferent lectori.
- Book III: on the position of the 42 constellations with respect to the celestial circles and the adjacent constellations; the way it rises above and sets below the horizon; the number and position of the stars within each constellation.
- Book IV: on the celestial circles and the constellations which are positioned on them; on the day and night; the paranatellonta; on the sun, moon and the five planets.
Incipits and excipits:
- Book I: Etsi te studio grammaticae artis inductum ... simili causa posse constitui suspicamur.
- Book II: Sed quoniam quae nobis de terrae positione ... circulum deformatum, quem supra demonstravimus.
- Book III: Igitur incipiemus a polo boreo protinus dicere ... nobis erunt dicta; reliqua protinus dicemus.
- Book IV: Quoniam in initio sphaerae circuli V ... cum sol ab aestivo circulo redit.
There are more than 80 manuscripts, listed by Ghislaine Viré (1981) and André Le Boeuffle (2002).
- Bern, Bürgerbibliothek, Cod. 45
- Leiden, Universitaire Bibliotheken, VLO 15
- Leiden, Universitaire Bibliotheken, GRO 21
- Paris, Bibliothèque nationale de France, MS lat. 7299A
- Vatican, BAV Reg. lat. 1260 (44v-83v)
- Paris, Bibliothèque nationale de France, MS lat. 8728 (digitised)
- Vatican, Biblioteca apostolica vaticana, Vat. lat. 3109 (s. XV)
- Vatican, Biblioteca apostolica vaticana, Vat. lat. 3110 (s. XIV)
- Vatican, Biblioteca apostolica vaticana, Vat. lat. 11460 (s. XV)
- Vatican, Biblioteca apostolica vaticana, Pal. lat. 1363 (s. XII)
- Vienna, Österreichische Nationalbibliothek, Cod. 51