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imported>P1umtree (Created page with " To find the Distance of the Moon from the Earth by its horizontal parallax, or the angle Subtended at the moon by the semidiameter of the earth. Let e be the Earth,...") |
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To find the Distance of the Moon from the Earth by its horizontal parallax, or the angle Subtended at the moon by the semidiameter of the earth. | To find the Distance of the Moon from the Earth by its horizontal parallax, or the angle Subtended at the moon by the semidiameter of the earth. | ||
Let e be the Earth, E the Moon in the meridan, cI the natural horizon, Ho the sensible. The moon circumvolves the earth in just H24. . . m47. . .Sec38. Therefore she goes from E to I in H6...m11... | Let e be the Earth, E the Moon in the meridan, cI the natural horizon, Ho the sensible. The moon circumvolves the earth in just H24. . . m47. . .Sec38. Therefore she goes from E to I in H6...m11...S54.5: Observe by the quadrant De when the moon is in the meridian, See the exact time in which she passes from thence to the sensible horizon when she will have gone over just 90 degrees on the quadrant. | ||
Then say -- As the time of the moon's passing from E to o: (which is found to be 6 hours [[unclear]] minutes) is to 90°: so is the time of its pasing from E to I to the number of degrees which AI cuts off, or which measure the angle EAL. From which subtract 90°, and the remainder will be the angle OAI -- AIC, which is found to be 57'..18" the moon's horizontal parallax 90° _ 57'..18"= | Then say -- As the time of the moon's passing from E to o: (which is found to be 6 hours [[unclear]] minutes) is to 90°: so is the time of its pasing from E to I to the number of degrees which AI cuts off, or which measure the angle EAL. From which subtract 90°, and the remainder will be the angle OAI -- AIC, which is found to be 57'..18" the moon's horizontal parallax 90° _ 57'..18"=89..2'..42" Then in the triangle OAI, we have the angles of one side (AC) given to find the side CI | ||
Diagram showing angles referenced in text is in lower left corner of the page. | Diagram showing angles referenced in text is in lower left corner of the page. | ||
Latest revision as of 17:19, 10 September 2020
To find the Distance of the Moon from the Earth by its horizontal parallax, or the angle Subtended at the moon by the semidiameter of the earth.
Let e be the Earth, E the Moon in the meridan, cI the natural horizon, Ho the sensible. The moon circumvolves the earth in just H24. . . m47. . .Sec38. Therefore she goes from E to I in H6...m11...S54.5: Observe by the quadrant De when the moon is in the meridian, See the exact time in which she passes from thence to the sensible horizon when she will have gone over just 90 degrees on the quadrant. Then say -- As the time of the moon's passing from E to o: (which is found to be 6 hours unclear minutes) is to 90°: so is the time of its pasing from E to I to the number of degrees which AI cuts off, or which measure the angle EAL. From which subtract 90°, and the remainder will be the angle OAI -- AIC, which is found to be 57'..18" the moon's horizontal parallax 90° _ 57'..18"=89..2'..42" Then in the triangle OAI, we have the angles of one side (AC) given to find the side CI
Diagram showing angles referenced in text is in lower left corner of the page.