Page:Description and Use of a New Celestial Planisphere.pdf/14



AKE any Sector, or Gunter's Rule, (but the Sector is the bet, becaue it can be set to any Radius) and, with a pair of compaes, take the parallel ditance of 60°, and 60° in the Chords, or the parallel ditance of 45° in the Semi-Tangents, opening the Sector to any Radius as will bet uit your Plane; with this ditance weep a circle in the middle of your Plane, which is the Equinoctial, and mut be divided into 360 equal parts, or degrees; and alo into 24 hours, at the rate of 15° per hour; beginning where the degrees do; this circle is the Right Acenion in time, and degrees—in this cae, the center of the Sector is the pole of the projection, and the parallel of 45° is the radius of the Equinoctial; and, as the Tropic of Cancer is 23° 28' from the Equinoctial towards the Pole, take the parallel ditance of thee degrees (counting them doubly)