Scripta clarissimi mathematici M. Ioannis Regiomontani, de torqueto, astrolabio armillari, regula magna ptolemaica, baculo[que] astronomico, & observationibus cometarum, aucta necessariis, Ioannis Schoneri ... additionibus. Item observationes motuum solis, ac stellarum tam fixarum [qua ...] erraticarum. Item libellus M. Georgii Purbachii de quadrato geometrico ...

It should not seem absurd that the extremity of the equinoctial circle is adorned with the names and degrees of the twelve signs, even though the signs themselves possess a different region in the heavens than the equinoctial. For this will promote both the brevity of the work and a not insignificant convenience, as will be explained below. And it will be permitted to call that circuit the equinoctial sign-bearer. From here arise two monthly tablets or 'tablets of the months' upon which the ecliptic circle rests, equal in size to the aforementioned equinoctial circle but somewhat different in appearance; for inside the circle of signs, which will be named the ecliptic sign-bearer, it was appropriate to place the annual circle divided into twelve months. Although the ecliptic circle never touches the equinoctial, it is not equidistant from it, for if the flat surfaces of such circles are understood to be extended to the narrower part of the monthly tablets, they will undoubtedly meet, forming an angle equal to the one that the equinoctial makes with the celestial ecliptic, the magnitude of which is defined by twenty-three degrees and almost a half, as we are taught by organic inspections in this our time. Furthermore, such a collection of the two aforementioned circles together with the two monthly tablets will not unjustly be called the region of the signs, because their names are frequently seen therein. A certain eared ruler is adapted to the ecliptic circle, the extremities of which, very sharp and diametrically opposed to each other, are set to traverse the degrees of the ecliptic sign-bearer and the days of the annual circle on both sides. We shall not wrongly call it the ruler of longitude, because it indicates the positions of all stars according to the longitude of the zodiac, whether it walks in the solar orbit or deviates to the northern or southern side. The small ears subsequently growing from this ruler are adorned with alternating holes for receiving the ray of the Sun, or of any other star running in the solar path, for for those that will lean to either side of the ecliptic, I have added another smaller ruler, with smaller and perforated ears, to the circle of latitude.