CLAUDIUS PTOLEMY:

TETRABIBLOS

OR THE QUADRIPARTITE MATHEMATICAL TREATISE

24. Of Applications and Separations and the Other Powers.

In general those which precede are said to "apply" to those which follow, and those that follow to "be separated" from those that precede, when the interval between them is not great. Such a relation is taken to exist whether it happens by bodily conjunction or through one of the traditional aspects; except that with respect to the bodily applications and separations of the heavenly bodies it is of use also to observe their latitudes, in order that only those passages may be accepted which are found to be on the same side of the ecliptic. In the case of applications and separation s by aspect, however, such a practice is superfluous, because all rays always fall and similarly converge from every direction upon the same point, that is, the centre of the earth.
From all this then, it is easy to see that the quality of each of the stars must be examined with reference both to its own natural character and that also of the signs that include it, or likewise from the character of its aspects to the sun and the angles, in the manner which we have explained. Their power must be determined, in the first place, from the fact that they are either oriental and adding to their proper motion - for then they are most powerful - or occidental and diminishing in speed, for then their energy is weaker. Second, it is to be determined from their position relative to the horizon; for they are most powerful when they are in mid-heaven or approaching it, and second when they are exactly on the horizon or in the succedent place; their power is greater when they are in the orient, and less when they culminate beneath the earth or are in some other aspect to the orient; if they bear no aspect at all to the orient they are entirely powerless.




Ptolemy's Tetrabiblos

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