First edition of Apianuss first full description of the "horoscopion", a geometric quadrant which could be used as a scientific instrument for determining the hour of the day astronomically and for measuring distances, heights and depths. In this work, Apianus describes not only the instrument itself, but also the practical application of it. The work is divided into four parts. The first part describes the instrument, the second part is strictly astronomical, the third part is devoted to solving problems by measuring heights, distances and depths of distant objects.
The Horoscopion Apiani was printed at the authors own press at Ingolstadt. It was dedicated to the Holy Roman Emperor Charles V, who granted Apianus a printing monopoly in 1532 and 1534 and who appointed Apianus later as his court mathematician. This work was, like all of Apianuss works, very influential and can therefore be regarded as a treasure for 16th-century mathematical and astronomical knowledge.
Binding slightly rubbed, many wormholes throughout the whole book (sometimes affecting the text), a few small tears in the lower margin, last pages slightly water stained, first endpaper a bit crinkled, but still a rare work in good condition. Adams, A-1290; Honeyman 112; Houzeau & Lancaster 2395; Stillwell 811; USTC 664150; Zinner, Astronomischen Literatur, 1512; for the author: DSB I, pp. 178-179.