Astronomia Britannica exhibiting the doctrine of the sphere, and theory of the planets decimally by trigonometry, and by tables : fitted for the meridian of London ... / by John Newton ...

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Title
Astronomia Britannica exhibiting the doctrine of the sphere, and theory of the planets decimally by trigonometry, and by tables : fitted for the meridian of London ... / by John Newton ...
Author
Newton, John, 1622-1678.
Publication
London :: Printed for the author by R. and W. Leybourn, and are to be sold by Thomas Piercepoint ...,
1657.
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Subject terms
Astronomy -- Early works to 1800.
Planetary theory -- Early works to 1800.
Astronomy -- Mathematics -- Early works to 1800.
Cite this Item
"Astronomia Britannica exhibiting the doctrine of the sphere, and theory of the planets decimally by trigonometry, and by tables : fitted for the meridian of London ... / by John Newton ..." In the digital collection Early English Books Online. https://name.umdl.umich.edu/A52255.0001.001. University of Michigan Library Digital Collections. Accessed May 23, 2024.

Pages

CHAP. 24. Of the Ark of Direction, what it is, and how to finde it.

AStrologers use to fore-tel the general Fortune of any Native by the consideration of the 12 Houses, but the particular time, in which we may expect, what is promised by the position of the Heavens at the time of the Birth, they measure out by the arke of Direction. That is, by the distance of the Significators from there Promittors reckoned in the Aequator, by Significators usually meaning, the Ascendent, Mid∣heaven, Sun, Moon, and part of Fortune: And by Promittors, the seve∣ral Aspects of these Significators to the Planets, or the twelve Houses.

For the clearer understanding of what the arke of Direction is, in the Diagram of the last Chapter, Let A D C represent the Meridian D V S E the Aequator, A C the Horizon, M the North-pole, A H C a Circle of position above the Earth, H B and N R two parallels of Declination. H the Significator, D O his right Ascension. H O his Declination. R the Promittor D S his right Ascension, R S his declination. Now when the Promittor at R comes to N, it is in the same Circle of position with the Significator at H, and the Circle of Declination M R S will be changed into the Circle of Declination M N V, and then the arch of the Aequator, D V is the Right Ascension of the Promittor at N, and therefore the arch of the Aequator V S is the arke of Direction sought. And the manner of finding thereof is as various, as the position of the Significator may be in the figure, which is threefold, viz. Either in the Meridian, in the Signes Ascending, or in the Signes Descending.

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