- Astronomicum Caesareum. Ingolstadt: at the author’s press, May 1540
This Astronomicum Caesareum, dedicated to Emperor Charles V and King Ferdinand, has been described as "a miracle of printing in folio format: most of the astronomical schemes and instruments have up to six movable parts. Apian received three thousand gold florins from the dedicatees [and] personal appointment as court mathematician" (Woodward). This work contains a broad analysis of Ptolemaic astronomy and 'is notable for Apianus’ pioneering observations of comets (he describes the appearances and characteristics of five comets, including Halley's) and his statement that comets point their tails away from the sun' (DSB). The text also describes the use of solar eclipses to measure longitude; the author’s inventions of the meteorscope (for solving problems in spherical trigonometry) and the torquetum (a predecessor of the equatorial telescope); and a variety of astrological concerns. Most of Apianus’ observations and theories are illustrated by his inclusion of intricate volvelles, which he believed to be of greater use in providing information on the position and movement of celestial bodies, rather than mathematical formulae.
APIANUS IS ALSO NOTED FOR INTRODUCING ARABIC STAR NAMES INTO HIS MAPS. In the present work Apianus includes a revision of his 1536 star chart, with the addition of two more Arabic star names (Angentenar in Eridanus, and Yed in Ophiuchus), and two Latin star names which do not appear the 1536 edition. Apianus knew the work of Islamic astronomer Abu 'l-Husain al-Sufi (A.D. 903-986). "Al-Sufi, in his Book on the constellations (written around A.D. 964), gave a detailed account of the 48 classical constellations (which the Arabs knew through translations of Greek astronomical works and through pictorial representations on globes from other sources), complemented by records of star names of indigenous Arabic origin which he took pains to identify astronomically with the respective Ptolemaic stars. It was from this section on the indigenous Arabic star names in al-Sufi's book that Apian extracted a number of names and mentioned them in his own writings, most of them in the chapter in constellations in his Astronomicum Caesareum of 1540" (Kunitzsch).
The collation of the work is understandably complex. Gingerich calls for an ideal copy to have 83 volvelles, as here.