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that it seems to turn about as if it were borne up by them; therefore, by some it is termed the axle-tree of the world, as if there was a line supposed to be drawn from one pole through the centre of the earth to the other pole, and the earth turning thereon; though Holy Writ tells us "The Lord hangeth the earth upon nothing, it being upheld by his mighty power." The Pole Arctic, or North Pole, is elevated above our horizon about fifty-one degrees, and the stars within that distance from it never set with us, but keep their course round it daily; so, likewise, those that are that distance from the South Pole never rise with us, but perform their course in the like order.
Azimuths are supposed lines, or circles of distance from the meridian, drawn from the zenith to any degree, or two degrees of the horizon, or according to the thirty-two points of the mariner’s compass, so that in travelling or sailing any way, supposing a circle to go from our zenith directly before us to the horizon, is the azimuth, called the vertical point, as well as the zenith.
Almicantharats, or Almadarats, or Circles of Altitude, are imaginery lines passing through the meridian parallel with the horizon.
Sphere is a round body representing the frame of the whole world, as the the circle of the heaven and the earth. This is sometimes called a martial sphere, for the orbs of the planets are called their spheres, that is, the circles in which they move.
Ascension is the rising of any star, or any part of the ecliptic above the horizon. Decension is its going down.
Right Ascension of a star, is that part of the equinox that riseth or setteth with a star in the right sphere; but an oblique sphere, is that part of the equinoctial in degrees, containing between the first point of Aries, and that part of the equinoctial which passeth by the meridian with the centre of the star.
Oblique Ascension is a part of the equinoctial in degrees containing between the beginning of Aries and that of the equinox, which rises with any star or part of the ecliptic in an oblique sphere.
Essential Difference is the difference between the right and oblique ascension, or the number of degrees
