Astronomical Images : Volvelles for the true position of the Moon

Lazarus Beham

Astronomical Images

<p style='text-align: justify;'>This engraved paper instrument is from Lazarus Beham's <i>Buch von der Astronomie</i>. Beham's text was preceded by a calendar for the years 1477-1537 by Johannes Regiomontanus, from which this instrument is taken. The instrument was designed to work out the true position of the Moon using two volvelles (paper discs) in conjunction with a thread (now lost) and tables printed elsewhere in the book. This kind of instrument required precision (its markings on the outer rim of each circle represents two degrees), which may be the reason that the technique of engraving was used.</p>