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 ...
Newton, John, 1622-1678.
CHAP. 10. How to finde the Ascensionall Difference.
THe Ascensional Difference, is nothing else but the difference be∣tweene the ascension of any point of the ecliptique in a Right Sphere, and the Ascension of the same point in an oblique Sphaere, as in the annexed Diagram, Let A G E V represent the
[illustration]
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Meridian, E M T the Horizon, G D M C V the Aequator, D B part of the Zodiac, A the Pole thereof, D the beginning of Aries, V T the com∣plement of the Poles elevation, B C the Suns Declination, D C the Right ascension, M C the ascensional Difference.
Then in the Right angled sphaericall Triangle B M C we have limited. 1. The angle C M B the complement of the Pole 38. 46667. Secondly, the side B C 19 deg. the Suns Declination, hence to finde, the ascension∣al difference M C the Analogie is.
As the Cotangent of the poles Elevation, is to Radius. So is the tangent of the planets Declination, to the sine of the ascensionall difference.
| As the tangent of C M B | 38. 46667. co. ar. | 0. 09991•6 |
| Is to Radius | 10. 000000 | |
| So is tangent of B C | 22. 0291 | 9. 6070441 |
| To the sine of M C | 30. 61613 | 9. 7069577 |
which is the Ascensionall Difference sought.
