The description and use of the universall quadrat.: By which is performed, with great expedition, the whole doctrine of triangles, both plain and sphericall, two severall wayes with ease and exactness. Also the resolution of such propositions as are most usefull in astronomie, navigation, and dialling. By which is also performed the proportioning of lines and superficies: the measuring of all manner of land, board, glasse; timber, stone. &c. / By Thomas Stirrup, Philomathemat.

CHAP. V. Having the distance of the Sun from the next Equinoctial point, to finde his declination.

• AS the Radius is in proportion,
• To the sine of the Suns greatest declination:
• So the Sine of the Suns distance from the next equinoctial point,
• To the sine of the declination required.

Thus in the right angled spherical triangle ♈X♉ in the following Diagram, having the base ♈♉ 30 deg. (which is the Suns distance from the Equinoctial point ♈, he being in the beginning of ♉;) and the angle X♈♉ 23 degrees 30 minutes (the angle of the Suns greatest de∣clination) with the right angle at X, we may finde the side ♉X, the declination required.

For if we place the threed at the intersection of the contrary sine of 90 degrees, with the right sine of 23 de∣grees 30 minutes, it will cut the contrary sine of 30 deg. at the right sineof of 11 deg. 30 minutes.

Or if we place the threed at the intersection of the contrary sine of 90 deg. with the right sine of 30 deg. it will cut the contrary sine of 23 deg. 30 min. at the right sine of 11 deg. 30 min. & so much is the side ♉X, the de∣clination of the Sun in the beginning of ♉, which was re∣quired. The like declination hath the beginning of ♍, ♏, & ♓, all being of equal distance from their next equinocti∣al

points; the like holdeth of all the other points of the Ecliptick; so that having the declination of every degree in one quarter all the rest are known.