EXAMPLE I.

_To find the time of New Moon in_ April 1764, _N. S._

+------------------------------------+----------+-------------+-------------+

| | | Sun’s Anom. | Moon’s Ano. |

| | D. H. M. +-------------+-------------+

| | | s ° ʹ | s ° ʹ |

| +----------+-------------+-------------+

| Tab. II. Mean time of New Moon | | | |

| in _March_ | 2 8 57 | 8 2 23 | 10 13 32 |

| Add, for Lunation, from Tab. VI. | 29 12 44 | 0 29 6 | 0 25 49 |

| | -------- | ---------- | ---------- |

| Mean New Moon and Anomaly | 31 21 41 | 0 1 29 | 11 9 21 |

| To which Time add the Moon’s | +-------------+ |

| Ann. Equ. Tab. VIII. | + 0 22 | Equ. Moon’s Anom. - 20 |

| And it gives the Mean time | -------- | ---------- |

| corrected | 31 22 3 | Anom. cor. 11 9 1 |

| From which subtract the Moon’s | | Sun’s Equat. + 1 56 |

| elliptic Equ. Tab. X. | - 3 10 | ---------- |

| | -------- | Moon’s Ano. 11 10 57 |

| And it gives the Mean time equated | 31 18 53 +---------------------------+

| To which add the Sun’s Equation, | | h. m. |

| Tab. XI. | + 3 32 | Moon’s ann. Equ. 0 22 add |

| And it gives the true time | -------- | Her ellipt. Equ. 3 10 sub.|

| of Conjunction | 31 22 25 | Sun’s Equation 3 32 add |

| +----------+---------------------------+

| |

| Which true time answers to the first of _April_, at 25 minutes past 10 in |

| the forenoon: for, as the Astronomical Day begins at Noon, then 22 |

| hours 25 min. after the Noon of _March 31_, is _April 1_, at 10 hours |

| 25 min. in the Forenoon. |

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Astronomy Explained Upon Sir Isaac Newton's Principles And made easy to those who have not studied mathematics · 第 201 / 275 题