The Tables of Directions
By 1467, during his stay in Hungary, and with the cooperation of the royal astronomer, Martin Bylica, Regiomontanus composed his Tabulae directionum et profectionum, commonly known as the Tables of Directions. This work contains the longitudes of the celestial bodies in relation to the daily rotation of the heavens. Regiomontanus also devised a method to divide the sky into twelve houses (duodecim domorum coeli) for drawing up the horoscopes, including their respective tables for casting these horoscopes. Shown here is a page from our copy of the editio princeps, published in Venice in 1490.