EXAMPLE V. Required the true time of Full Moon in April, Old Style, A. D. 30. March, 173, Add 4 lunation, Full Moon, 1700 years subtract, Full Moon April, First equation, Time once equated, and Arg. 4th. 6 5 31 43 4 21 59 20 + 5 9 39 47 10 9 54 37 18 53 Sun fro. Node 5 10 58 40 equation: 2 57 55 Arg.3d. equat. Arg. 2d equat. 6 8 29 38 6 - 2 54 Hence it appears, that the true time of Full Moon, in April, A. D. 30, old style, 8 26 44 was on the 6th day, at 25 m. 11 sec. past 1 33 VIII. in the evening. 6 8 25 11 1, shall make a number of complete centuries. ded to the given number of years before Christ, diminished by Precept 1. Find a year in the 18th century, which being ad en Year and Month before the Christian Æra. To calculate the true time of New or Full Moon in any giv and the remainder will denote the time and anomalies, &c. of New Moon in March, the above found year of the 18th century; the time and anomalies belonging to it from those of the mean 2. Find this number of centuries in Table VI. and subtract that year, proceed in the manner taught before. Then for the true time of that New Moon, in the mean New Moon in March, the given year before Christ any month of EXAMPLE VI. Required the true time of Full Moon in September, Old Style, the year be fore Christ, 201, The years 200 added to 1800. make 2000, or 20 centuries. By the Precepts. March 1800, Add lunation, From the sum, N. M. before Christ 201 6 lunations, Add half lunation, Book Sun's Anom. Moon's Anom. Sun fro. Node. 8 25.4 5 18 27 28 10 5 48 9 11 26 15 9 4 19 52 4th. equation. 5 25 Arg 3d.equat. Arg. 2d.equat. Moon eclipsed 8 58 Ans. The true time was September 22d 12 5 23 58 the given place is eastward of London; as inexample VII. gree that the meridian of the given place is westward of Lon don, or adding 4 minutes for every degree that the meridian of by subtracting 4 minutes from the tabular time, for every debut they will serve for any other place, with equal exactness, These Tables are calculated for the meridian of London EXAMPLE VII. Required the true time of the Full Moon at Babylon, Long. 36°, 25', 15" E, in The years 4007 added to 1793, make 5800, or 53 centuries. March 1793, Subtract 5800 years, N M.before Christ 4007 Add 57 lunations, 2 lunation, Full Moon, October, 1st. Equation, Full Moon at London, Add for Babylon, New Moon. Sun's Anom. Moon's Anom Sun fro. Noce 22 8 6 11 13 28 22 7 52 43 4 0 31 10 + 5 5 Sun fro. Node 1 26 27 26 and Arg. fo 8 29 20 Arg. 3d equat. Arg. 2d equat. 4th. equation. 22 16 22 S -- 4 22 16 17 10 53' 51 So that, on the meridian of London the true time was October 23d. at 17 m 2 sec. past IV. in the morning; but at Babylon, 'the true time was October 23d. at 42 m. 2 43 sec. past VI. in the morning. 41 This is supposed by some to have been 22 18 42 43 the year of the Creation, 22 16 17 2 25 en year after the 19th. Century. and anomalies, &c. of New Moon in March, old style, for that century with that of the year proposed, and take out the time PRECEPT 1. Find a year of the same number in the 18th. To calculate the true time of New or Full Moon in any giv year, in Table I. take out the first New Moon, with its anomalies, for these com the given year in which the New or Full Moon is required; and the above-mentioned year in the 18th. century, will answer to 2. Take so many years from Table VI. as, when added to plete centuries. Moon beyond the 31st of March; as in the following example : malies, when the above mentioned addition carries the New shewn above, only remember to subtract a lunation and its ano3. Add all these together, and then work in all respects as EXAMPLE VIII, Required the true mean time of New Moon, at Cambridge in North America, Long. 71° 20', W. in July, Oid Style, A. D. 2180. Four centuries (or 400 years) added to A. D. 1780, make 2180. By the Precepts; New Moon. Sun's Anom. Moon's Anom Sun tro. Node March, 1780, Add 400 years, Subtract 1 lunation, True time at London, Sub. for Cambridge, True time there. 7 20 53 41 10 5 22 33 2 9 38 38 9 24 8 Arg.3d. equat. Arg. 2d equat. + 8 6 17 49 + 3 56 6 21 45 +1 8 Hence it appears, that the time of that 6 22 53 45 m.20 sec. sooner; viz. at 37 m. 33 sec. 4 45 20 past I o'clock, P. M. 8 1 37 33 adding or subtracting whole hundreds of years to or from any In keeping by the old style, we are always sure to be right, by given year in the 18th century, on account of the leap-year's not coming in regularly every But in the new style we may be very liable to make mistakes, fourth year: And therefore, when we go without the limits of the 18th century, we had best keep to the old style, and at the end of the calculation reduce the time to the new. Thus, in the 22d century there will be 14 days difference between the styles; and therefore, the true time of New Moon in this last example being reduced to the new style, will be the 22d of July, at 37 m. 33 sec. past 1 P. M. To find the times of mean New and Full Moon for every month in the year. PRECEPT 1. Find the mean time of New and Full Moon in the month of January, as already taught, and to these times add a mean lunation, viz. 29 D. i2 H. 44 M. 3 S. continually, rejecting the days in the month wherein the mean New or Full Moon is required, and the results will denote the times required. EXAMPLE. Let it be required to find the mean New and Full Moons in every month of the year 1797. PERMISCUOUS QUESTIONS. 1. Required the true mean time of New Moon in May, old style, the year before Christ 585, and the Sun's distance, at that time, from the Moon's ascending node? Ans. True New Moon was on the 28th day, at 2 m. 31 sec. past IV in the evening; and the Sun's distance from node was 3 deg. 50 m. 47 sec. (Sun eclipsed.) 2. Required the time of true New Moon, and Sun's distance from the node, in July 1890 A. D. old style? |