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卷七十三 志第二十六 律曆六

Volume 73 Treatises 26: Measures and Calendar 6

Chapter 73 of 宋史 · History of Song
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Chapter 73
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1
Chongtian Calendar
2
Procedure for Conjunction and Eclipse
3
Conjunction terminal parts: 288,177, 4,277 seconds.
4
Conjunction terminal day: 27, remainder 2,247, 4,277 seconds.
5
Conjunction mid-day: 13, remainder 6,418, 738½ seconds.
6
New-moon discrepancy day: 2, remainder 3,371, 5,723 seconds.
7
Rear limit day: 1, remainder 1,685, 7,861½ seconds.
8
Full-moon stride: 14, remainder 8,104, 50 seconds.
9
$
Front limit day: 12, remainder 4,732, 9,277 seconds. Crossing rate: 141.
10
Crossing number: 1,796.
11
Conjunction terminal degree: 363° 76'.
12
Conjunction image: 90° 94'.
13
Half-conjunction: 181° 88'.
14
Solar-path eclipse limit: 4,200.
15
Solar-path fixed divisor: 420.
16
Lunar-path eclipse limit: 7,000.
17
Lunar-path fixed divisor: 700.
18
滿滿
To derive entry into conjunction at hour-of-addition for the eleventh-month beginning at civil new year: set the accumulated parts for that month-beginning, discard full conjunction terminal parts and seconds, divide the remainder by the pivot divisor for days with the remainder as parts and seconds, and obtain the generalized conjunction day and remainder in seconds at hour-of-addition for the civil new-year month-beginning.
19
滿
To find the next month-beginning and full moon entering conjunction: starting from the civil new-year month-beginning generalized conjunction day and remainder seconds at hour-of-addition, for the next month-beginning add the new-moon discrepancy in days and remainder seconds; To find the full moon, add the full-moon stride and remainder-seconds; cast out full crossing-termination days and remainder-seconds to obtain the hour-of-addition entry for the next month-beginning and full moon. Subtracting each mean syzygy's minor remainder yields the general crossing day and remainder-seconds at midnight for that month-beginning or full moon.
20
退退
To find fixed month-beginning midnight crossing entry: start from mean syzygy midnight crossing; if the fixed syzygy's major remainder advances or retreats, adjust the crossing day accordingly, otherwise use the mean value as fixed.
21
滿
For the next fixed month-beginning midnight crossing entry: from each prior fixed month-beginning midnight entry, add two days in a long month and one in a short month, and always add 8,342 remainder and 5,723 seconds. To advance day by day, add one day cumulatively, cast out full crossing-termination days and remainder-seconds, and obtain the next fixed month-beginning and each day's midnight general crossing day and remainder-seconds.
22
To find syzygy hour-of-addition regular crossing day: set mean syzygy general crossing day and remainder-seconds, apply entry-into-qi waxing-waning fixed numbers (waxing subtract, waning add), and obtain syzygy regular crossing day and remainder-seconds.
23
滿退
To find syzygy hour-of-addition fixed crossing day: set entry-into-rotation waxing-waning fixed number, multiply by crossing rate and divide by crossing number, waxing subtract and waning add to the regular crossing remainder, adjust the day as needed, and obtain fixed crossing day and remainder-seconds at hour-of-addition.
24
To find the moon's solar-path or lunar-path: if the syzygy's fixed crossing day and remainder-seconds are at or below the middle day and remainder-seconds, the moon is in the solar-path; if at or above the middle day and remainder-seconds, subtract the middle day; the moon is in the lunar-path. For fixed crossing days: solar-path at the start and lunar-path at the end marks crossing beginning; lunar-path at the start and solar-path at the end marks crossing middle.
25
To find syzygy hour accumulated solar-path or lunar-path degrees: set the moon's entered yin-yang day and remainder, multiply the remainder by 100, and divide by the pivot divisor to obtain simplified parts.
26
退
Multiply by 999, divide by 68 for degrees, reduce any remainder to parts, and obtain syzygy hour accumulated solar-path or lunar-path degrees and parts. If the moon is in the solar-path, this is solar-path accumulated degrees; if the moon is in the lunar-path, this is lunar-path accumulated degrees.
27
滿滿
To find syzygy hour lunar latitude: set entered yin-yang accumulated degrees and parts; at or below the crossing image counts as the young image; if above, cover and subtract half-crossing; the remainder is entry into the old image. Set entered young or old image degrees and parts, multiply by five, subtract from 1,010, multiply the remainder by the image degrees and parts, divide by 84, and place in the upper row; Again set entered young or old image degrees and parts; at or below half an image counts as the initial limit; if above, subtract half an image; the remainder is entry into the final limit. Place initial and final limit bases above and half-image degrees below, subtract and multiply (divide by 40), subtract for the initial limit and add for the final limit, convert hundreds to degrees, and obtain syzygy hour lunar latitude in degrees and parts.
28
便
To find the eclipse-fixed remainder: set the fixed month-beginning minor remainder; if at or below the half method, add back the half method to obtain the before-noon fraction; if above, subtract the half method to obtain the after-noon fraction. Place before- and after-noon parts above and the half method below, subtract and multiply, divide before-noon by 31,770 and after-noon by 13,885, and obtain the time difference for each. Subtract the time difference before noon and add it after noon to the fixed month-beginning minor remainder to obtain the eclipse-fixed minor remainder. Add the time difference to the before- and after-noon parts to obtain the before- and after-noon fixed parts. For a lunar eclipse, the fixed full-moon minor remainder itself serves as the eclipse-fixed minor remainder.
29
滿滿
To find eclipse maximum watch and quarter: divide the eclipse-fixed minor remainder by the watch divisor for watches, advance the remainder one place and divide by the quarter divisor for quarters, and obtain quarter parts. Count watches from zi-zheng, outside the count, to obtain eclipse maximum watch, quarter, and parts.
30
滿 滿
To find qi difference: set the new-moon middle accumulation, cast out the two-solstice limit, and if the remainder is at or below one image it is initial; if above, cover and subtract the two-solstice limit; the remainder is final. Square each case, shift two places, divide by 236, subtract from 3,533, and obtain qi difference. Multiply by the noon-distance fixed parts, divide by half day-part, subtract from qi difference, and obtain the fixed number. After the spring equinox: subtract at crossing beginning and add at crossing middle; after the autumn equinox: add at crossing beginning and subtract at crossing middle.
31
滿滿
To find quarter difference: set new-moon middle accumulation, cast out two-solstice limit, subtract and multiply against the limit (divide by 236), multiply by noon-distance fixed parts, multiply by four, divide by the pivot divisor, and obtain the fixed number. After the winter solstice, eclipse maximum falls before noon; after the summer solstice, it falls after noon. Add at crossing beginning and subtract at crossing middle. After the winter solstice, eclipse maximum falls after noon; after the summer solstice, it falls before noon. Add at crossing beginning and subtract at crossing middle.
32
To find solar entry into the eclipse limit: set fixed crossing day and remainder-seconds, apply qi-, quarter-, and time-difference fixed numbers, and if at or below the middle day and remainder-seconds there is no eclipse; if above, subtract the middle day and remainder-seconds; if at or below the rear limit and at or above the forward limit, the syzygy has entered the eclipse limit; at or below the rear limit is the after-crossing part; at or above the forward limit, cover and subtract the middle day; the remainder is the before-crossing part.
33
To find solar eclipse magnitude: set before- and after-crossing parts; if at or below the solar-path eclipse limit, that is the solar-path eclipse fixed part; if above, cover and subtract 11,200; the remainder is the lunar-path eclipse fixed part; if subtraction cannot be completed, there is no eclipse.
34
退
Divide each by the solar-path fixed divisor to obtain the eclipse major part, reduce any remainder to minor parts, and treat half or above as half-strong and below half as half-weak. Take the major part on a scale of ten to obtain solar eclipse magnitude.
35
To find solar eclipse general use-parts: set month-beginning yin-yang eclipse fixed part and hundred-reduce; for solar-path place 14 below and for lunar-path 140 below, subtract and multiply (shift two places), divide by 185 (solar-path) or 514 (lunar-path), and obtain solar eclipse general use-parts.
36
To find lunar entry into the eclipse limit: inspect the moon's yin-yang day and remainder; if at or below the rear limit, that is the after-crossing part; at or above the forward limit, cover and subtract the middle day to obtain the before-crossing part.
37
退
To find lunar eclipse magnitude: set before- and after-crossing parts; if at or below 3,200, the eclipse is total; if above, subtract 10,200; if subtraction cannot be completed, there is no eclipse; divide the remainder by 700 for the major part, reduce any remainder to minor parts, and treat half or above as half-strong and half or below as half-weak. Take the major part on a scale of ten to obtain lunar eclipse magnitude.
38
退
To find lunar eclipse general use-parts: set full-moon before- and after-crossing parts, shift one place and square, divide by 935 (crossing beginning) or 1,156 (crossing middle), and subtract from the quarter rate of 1,111 (crossing beginning) or 900 (crossing middle).
39
Each procedure yields the value sought.
40
To find eclipse fixed use-parts: multiply general use-parts by 1,337 and divide by the rotation fixed parts of the eclipse day to obtain the fixed use-part.
41
滿 滿滿
To find eclipse first diminishment, restoration fullness, and minor remainders: subtract the fixed use-part from the eclipse-greatest minor remainder for first diminishment; add the fixed use-part to the eclipse-greatest minor remainder for restoration fullness; each case then yields first diminishment and restoration fullness minor remainders. To find clock time, apply the eclipse-greatest procedure.
42
退 退
To find lunar eclipse watch and tally divisors: quadruple the full-moon dawn parts and shift one place to obtain the watch method; double that value and shift one place to obtain the tally method.
43
滿滿
To find lunar eclipse watch and tally entry: set first diminishment, eclipse maximum, and restoration fullness minor remainders; below dawn parts add dawn parts, above dusk parts subtract dusk parts; divide by the watch method for watch count, then by the tally method for tally count. Name from the first watch outside the count to obtain each entered watch and tally.
44
宿
To find syzygy eclipse-greatest lodge position: set mean syzygy entry-into-qi minor remainder, apply entry-into-qi and entry-into-rotation waxing-waning fixed numbers (waxing subtract, waning add), multiply by that day's ascending-descending parts and divide by the pivot divisor, add or subtract excess-deficit parts (add after solstice and before parts, subtract after parts and before solstice).
45
滿宿 宿
Hundred-reduce to parts and convert hundreds to degrees, apply excess-add and deficit-subtract to fixed syzygy hour-of-addition middle accumulation, add to the civil new-year winter solstice ecliptic solar degree at hour-of-addition, name the lodges, and obtain fixed syzygy hour-of-addition solar lodge position. At full moon add half a circuit of heaven and name as before to obtain month-beginning and full-moon eclipse-greatest lodge positions.
46
To find lunar eclipse total inner and outer quarter parts: set lunar eclipse before- and after-crossing parts, cover and subtract 3,200; if subtraction cannot be completed, the eclipse falls short of totality.
47
Hundred-reduce, place 64 below, subtract and multiply (shift two places), divide by 293 (crossing beginning) or 365 (crossing middle), multiply by fixed use-parts and divide by general use-parts, and obtain lunar eclipse total inner quarter parts; cover and subtract the fixed use-part to obtain the total outer quarter part.
48
滿
To find the visible fraction when an eclipse is caught at sunrise or sunset: subtract rise or set parts from the eclipse-fixed minor remainder to obtain the horizon-partial difference; if the horizon-partial difference meets or exceeds the fixed use-part, no horizon-partial eclipse occurs at rise or set.
49
滿
Multiply the horizon-partial difference by the eclipsed fraction and divide by the fixed use-part; for a total lunar eclipse, subtract the total inner quarter part from the horizon-partial difference, divide the remainder and eclipsed fraction by the total outer quarter part; if subtraction cannot be completed, the eclipse is partially total at rise or set.
50
退 退
Subtract the result from the eclipsed fraction to obtain the visible fraction at rise or set with horizon partial eclipse. When a month-beginning solar eclipse maximum falls in daylight, at dawn the eclipse is still advancing and at dusk it has already retreated; if eclipse maximum falls at night, at dawn it has already retreated and at dusk it is still advancing. For a lunar eclipse, the same principle applies.
51
西 西 西
To find solar eclipse direction of first contact: with the sun in the lunar-path, first contact is northwest, maximum due north, and recovery northeast; with the sun in the solar-path, first contact is southwest, maximum due south, and recovery southeast. For eclipses of eight-tenths or greater, first contact is always due west and recovery due east. This assumes an observer on the local meridian; for other latitudes, determine direction from the ecliptic's tilt and the moon's course.
52
西 西 西 滿
To find lunar eclipse direction of first contact: with the moon in the lunar-path, first contact is southeast, maximum due south, and recovery southwest; with the moon in the solar-path, first contact is northeast, maximum due north, and recovery northwest. For eclipses of eight-tenths or greater, first contact is always due east and recovery due west. This also assumes an observer on the local meridian; for other latitudes, follow the solar eclipse directions to determine first diminishment and restoration to full.
53
Step Five Planets
54
Five-planet conjunction stride: 15° 21', 90".
55
Jupiter circuit rate: 4,224,058, 32 seconds.
56
Circuit day: 398, remainder 9,238, 32 seconds.
57
Precession: 103, 6 seconds.
58
Heliacal visibility: 13.
59
Jupiter excess-deficit calendar. Mars circuit rate: 8,259,366, 59 seconds.
60
Circuit day: 779, remainder 9,756, 59 seconds.
61
Precession: 103, 53 seconds.
62
Heliacal visibility: 20.
63
Mars excess-deficit calendar
64
Saturn circuit rate: 4,003,872, 39 seconds.
65
Circuit day: 378, remainder 852, 39 seconds.
66
Precession: 103, 78 seconds.
67
Heliacal visibility: 16.
68
Saturn excess-deficit calendar. Venus circuit rate: 6,183,599, 16 seconds.
69
Circuit day: 583, remainder 9,629, 16 seconds.
70
Precession: 130, 80 seconds.
71
Evening visibility morning concealment degree: 11.
72
Morning visibility evening concealment degree: 9.
73
Venus excess-deficit calendar
74
Mercury circuit rate: 1,227,170, 28 seconds.
75
Circuit day: 115, remainder 9,320, 28 seconds.
76
Precession: 103, 94 seconds.
77
Evening visibility morning concealment degree: 14.
78
Morning visibility evening concealment degree: 21.
79
Mercury excess-deficit calendar
80
滿滿退 退
To find each planet's central accumulation and central star for all variations after civil new-year winter solstice: set the qi accumulated parts, cast out each star's circuit rate, subtract the remainder again from the circuit rate, divide by the pivot divisor for days with the remainder as parts, and obtain the mean-conjunction central accumulation after civil new-year winter solstice; Name the result and accumulate the mean-conjunction central star; add each segment's variation days and degrees cumulatively to obtain the central accumulation and central star for all variations. For segments in retrograde motion, use the variation degree; subtract cumulatively to obtain that star's variation central star.
81
滿滿退
To find entry into the calendar cycle for all five-planet variations: multiply that star's precession by accumulated years, cast out full circuit-of-heaven parts, convert the remainder to degrees and parts by the pivot divisor, subtract from that star's mean-conjunction central star, and obtain mean-conjunction entry into the calendar cycle; Add that star's variation limit degrees in order to obtain entry-into-calendar degree and parts for every variation.
82
滿
To find the excess-and-deficit fixed difference for all five-planet variations: set each star and variation's entry-into-calendar degree and parts; at or below half circuit-of-heaven counts as excess; if above half circuit-of-heaven, subtract it; the remainder is in deficit. Set the excess-and-deficit limit degree and parts, divide by the five-planet conjunction stride to obtain the conjunction count, and take the remainder as entry-into-conjunction degree and parts; Multiply the tabulated loss-and-gain rate for that conjunction, divide by the conjunction stride for parts, convert parts filling 100 to degrees, apply to the underlying excess-and-deficit accumulated degree, and obtain that star and variation's excess-and-deficit fixed difference. If using precomputed tables, take the tabulated difference below the conjunction degree entered.
83
退 退
For Jupiter, Mars, and Saturn in posterior retreat and posterior station: set the excess-and-deficit difference, array each star's excess-and-deficit extreme degree below, subtract below from above, multiply the remainder by the upper value and divide by 87; triple the result for Jupiter and Saturn, and use it directly for Mars; When in excess, subtract where beneficial and add where deficient; when in deficit, add where beneficial and subtract where deficient — apply to the segment excess-and-deficit difference to obtain the posterior retreat and posterior station fixed difference, and thereby the posterior slow initial segment fixed difference. Each case must be matched to the prior station fixed difference, observe excess and deficit at beginning and end, examine the gradation, and apply by taking from the greater and giving to the lesser.
84
To find the fixed accumulation for all five-planet variations: set each star and variation's central accumulation, add or subtract the variation's excess-and-deficit fixed difference according to excess or deficit, and obtain that star and variation's fixed accumulation and parts; Add the civil new-year winter solstice greater remainder and parts to obtain that star and variation's fixed day and parts; Cast out full era rules from the fixed day, name from jiazi outside the count, and obtain the day and double-hour.
85
To find which month and day each of the five planets' variations falls on: set each variation's fixed day and subtract the year's civil new-year mean month-beginning major remainder and parts; if the winter solstice major remainder is smaller and the mean month-beginning major remainder must be added first, add the era method before subtracting.
86
滿
Divide the remainder by the new-moon stride and parts to obtain the month count; the remainder gives the days and parts elapsed within the month. Count months forward from the eleventh month at civil new year, outside the count, to obtain that planet's variation days and parts since that month's mean month-beginning. Alternatively, set the fixed accumulation, add the civil new-year intercalary month and parts, divide by the new-moon stride for the month count, and obtain the same result.
87
滿
To find which qi-period day each planetary variation enters: set the fixed accumulation, divide by the qi stride and approximate parts for the qi count, and take the remainder as days and parts elapsed within the qi-period. Count qi-periods forward from the civil new-year winter solstice, outside the count, to obtain the qi day and parts at which the five planets' variations enter. When the fixed accumulation reaches a full year-circuit day and parts, cast it out; the remainder falls after the following year's civil new-year winter solstice.
88
To find each planetary variation's fixed star: set the variation mid-star and adjust by its excess-deficit fixed difference, adding for excess and subtracting for deficit; for Venus and Mercury, double the difference for Venus and triple it for Mercury before applying the adjustment.
89
宿 退
This yields the fixed star for each of the five planets' variations; Add to the civil new-year winter solstice ecliptic solar degree at hour-of-addition and assign the lodge to obtain that planet's variation fixed star lodge sequence and parts at hour-of-addition. For all five planets, the prior stationary point serves as the first-day fixed star of prior retrograde motion, and the subsequent stationary point serves as the first-day fixed star of subsequent slow motion.
90
To find each variation's first-day dawn-before-midnight fixed star: subtract the excess-deficit accumulated degrees at the next degree from those at the entered-conjunction degree of the planet's variation excess-deficit; the remainder is the degree's increment-decrement parts; Multiply by the variation's initial motion rate and hundred-reduce; use the result to adjust that day's initial motion rate — in the excess cycle, add for increment and subtract for decrement; In the deficit cycle, subtract for increment and add for decrement.
91
退 宿
This gives the initial motion accumulated rate; Also set one hundred parts, adjust it by the same amount, divide the initial motion accumulated rate by the result, and obtain the first-day fixed motion rate; Multiply by that rate's first-day approximate parts and hundred-reduce; subtract in direct motion and add in retrograde motion to that day's hour-of-addition fixed star to obtain the variation's dawn-before-midnight fixed star; Add to the winter solstice solar degree at that time and assign the lodge to obtain its lodge position.
92
To find each variation's day and degree rates: set the subsequent variation's fixed day and subtract this variation's fixed day; the remainder is that variation's day rate; Also set the subsequent variation's midnight fixed star and subtract this variation's midnight fixed star and parts; the remainder is that variation's degree rate and parts.
93
滿退
To find each variation's parallel motion: set its degree rate and parts, divide by its day rate to obtain parallel motion; convert any remainder by retreat-division into seconds, yielding parallel degrees and parts-seconds for each.
94
To find each variation's total difference: subtract this segment's parallel motion from the subsequent segment's parallel motion; the remainder is the generalized difference; Add the prior segment's generalized difference, multiply by four, divide by nine, and obtain the total difference. If the prior segment lacks a parallel motion for subtraction, subtract this segment's parallel motion from the subsequent segment's first-day motion parts for each case; the result is the half total difference; Double the result to obtain the total difference.
95
If the subsequent segment lacks a parallel motion for subtraction, subtract this segment's parallel motion from its last-day motion parts for each case; the result is the half total difference.
96
退 退退
For segments in prior and subsequent retrograde motion, set each segment's parallel motion, multiply by fourteen, divide by fifteen, and obtain the total difference. For Venus in evening retrograde, evening concealment, second conjunction, and morning retrograde, apply the direct-segment method in each case to obtain the desired values.
97
To find each segment's first- and last-day motion parts: halve the segment's total difference and add or subtract it from the segment's parallel motion — if the subsequent segment's motion parts are greater, subtract for the first day and add for the last; If the subsequent segment's motion parts are lesser, add for the first day and subtract for the last.
98
滿 退
Each planet's segment then yields first- and last-day motion in degrees and parts-seconds. When consecutive segments' parallel motion is both greater or both lesser, distribute the correction evenly; Likewise, when a segment's total difference is less than one major part, distribute the correction evenly. For retrograde segments, subtract half the total difference before the variation for the first day and add it for the last; For the subsequent variation, add for the first day and subtract for the last.
99
宿
To find each day's dawn-before-midnight star lodge position: set the segment's total difference, subtract the segment's day rate, and divide to obtain the day difference; Apply the day difference cumulatively to the first-day motion parts — if the subsequent segment's motion parts are lesser, decrement daily; If the subsequent segment's motion parts are greater, increment daily.
100
宿宿 退
This yields each day's motion in degrees and parts; Cumulatively add each day's motion degrees and parts to the planet's segment first-day dawn-before-midnight lodge position and assign lodges to obtain each day's star motion lodge sequence. In retrograde motion, cumulatively subtract each day's motion parts to obtain the desired lodge sequence.
101
宿
To find a given day's lodge position directly: set the sought day, subtract one, multiply by the day difference, and adjust the first-day motion parts — subtract if the subsequent motion parts are lesser; Add if the subsequent motion parts are greater.
102
宿 宿
This gives the sought day's motion parts; Add the daily motion parts and halve the sum; Multiply by the sought day to obtain the direct-seek accumulated degree; Add or subtract this from the star's first-day lodge position; Assign the lodge to obtain that day's star motion lodge sequence.
103
滿滿
To find each planet's fixed conjunction day and fixed star: subtract one hundred parts from the mean-conjunction first-day motion parts; use the remainder to reduce that day's solar excess-deficit into parts, converting hundreds of parts to days with the remainder as parts, and name the result the distance-from-conjunction difference day; Subtract the excess-deficit parts to obtain the distance-from-conjunction difference degree; Apply the difference day and difference degree to the mean-conjunction fixed accumulation and fixed star, adding when in deficit and subtracting when in excess, to obtain that star's fixed-conjunction day, fixed accumulation, and fixed star. For Venus and Mercury, subtract one hundred parts from the first-day motion parts, divide that day's solar excess-deficit parts by the remainder, and obtain the distance-from-conjunction difference day; Add the excess-deficit parts to obtain the distance-from-conjunction difference degree; Apply the difference day and difference degree, adding when in excess and subtracting when in deficit.
104
退
For Venus and Mercury in retrograde conjunction, add one hundred parts to the first-day motion parts, divide the solar excess-deficit parts by the sum, and obtain the distance-from-conjunction difference day; Subtract the distance-from-conjunction difference day from the excess-deficit parts to obtain the distance-from-conjunction difference degree; Apply the difference day and difference degree to the second-conjunction fixed accumulation and fixed star, subtracting when in excess and adding when in deficit, to obtain that star's second-conjunction fixed day, fixed accumulation, and fixed star.
105
For Venus and Mercury fixed accumulations, follow the visibility-and-concealment procedure in each case: first apply the excess-deficit difference, then adjust by the distance-from-conjunction difference day and difference degree.
106
To find Jupiter, Mars, and Saturn morning appearance and evening concealment fixed days: set each star's segment fixed accumulation, then add or subtract one-quadrant degree — add for morning appearance and subtract for evening concealment.
107
滿退
If at or below half circuit-of-heaven, square the value; if above, subtract from circuit-of-heaven degrees and parts and square the remainder; hundred-reduce to parts, multiply by that star's heliacal visibility degree, divide by fifteen, and obtain the difference; Then subtract one hundred parts from that segment's first-day motion parts, divide the difference by the remainder for days with the remainder as parts, and add or subtract the result from the fixed accumulation — add for morning appearance and subtract for evening concealment. Each then yields morning appearance and evening concealment fixed accumulation; Add the civil new-year winter solstice major remainder and parts, count from jiazi, outside the count, and obtain the day and time.
108
To find Venus and Mercury evening appearance and morning concealment fixed days: set each star's segment fixed accumulation, double the segment's excess-deficit difference and apply it to the fixed accumulation (add when in deficit, subtract when in excess), then add or subtract one-quadrant degree — subtract for evening appearance and add for morning concealment.
109
滿退
If at or below half circuit-of-heaven, square the value; if above, subtract from circuit-of-heaven degrees and square the remainder; hundred-reduce to parts, multiply by that star's heliacal visibility degree, divide by fifteen, and obtain the difference; Then subtract one hundred parts from that segment's first-day motion parts, divide the difference by the remainder for days with the remainder as parts, and add or subtract the result from the fixed accumulation — add for evening appearance and subtract for morning concealment.
110
Each then yields evening appearance and morning concealment fixed accumulation.
111
To find Venus and Mercury morning appearance and evening concealment fixed days: set the star's segment fixed accumulation, multiply the segment's excess-deficit difference by one hundred and apply it to the fixed accumulation, add one hundred parts to the daily motion parts and divide the difference, apply the result (add when in excess, subtract when in deficit), then add or subtract one-quadrant degree — add for morning appearance and subtract for evening concealment.
112
滿退
If at or below half circuit-of-heaven, square the value; if above, subtract from circuit-of-heaven degrees and square the remainder; hundred-reduce to parts, multiply by that star's heliacal visibility degree, divide by fifteen, and obtain the difference; Then set that segment's first-day motion parts to one hundred, divide the difference for days with the remainder as parts, and add or subtract the result from the fixed accumulation — add for morning appearance and subtract for evening concealment.
113
Each yields that star's morning appearance and evening concealment fixed accumulation.
114
When the calendar was finished it was adopted for the following jiazi year; on the dinghai new moon of the fifth month that year the predicted solar eclipse failed — the calculation showed an eclipse of two and a half parts, but observation found none.
115
使
An edict ordered observational verification. In the seventh year Jiang Deming, Director of the Inner Palace, was ordered to assemble calendar officials and compare measurements with the armillary sphere. At the time Zhou Cong said: "Ancient calendar-makers made star positions and eclipses over a thousand years align like a plumb line; now the calendar is finished yet fails verification, so the calendar method is not yet precise." Yang Hao and Yu Yuan also joined Cong in seeking comparative verification; Hao's method proved correct for Jupiter, Yuan's for Venus, and Cong's for the Moon and Saturn. An edict ordered these incorporated into the Chongtian Calendar. The revised rate constants are as follows:
116
Circuit-of-heaven parts: 3,868,066, 17 seconds.
117
Circuit-of-heaven: 365 degrees. Void fraction: 2,716, 17 seconds; approximate fraction: 25, 61 seconds.
118
Precession: 126, 17 seconds.
119
退
To find each variation's total difference: subtract this segment's parallel motion from the subsequent segment's parallel motion; the remainder is the generalized difference; Add the prior segment's generalized difference, multiply by four, retreat one place, and obtain the total difference. If the prior segment lacks a parallel motion for subtraction, subtract this segment's parallel motion from the subsequent segment's first-day motion parts for each case; the result is the half total difference; Double the result to obtain the total difference.
120
If the subsequent segment lacks a parallel motion for subtraction, subtract this segment's parallel motion from its last-day motion parts for each case; the result is the half total difference; Double the result to obtain the total difference.
121
退 退退
For segments in prior and subsequent retrograde motion, set each segment's parallel motion, multiply by fourteen, divide by fifteen, and obtain the total difference. For Venus in evening retrograde, evening concealment, second conjunction, and morning retrograde, apply the direct-segment method in each case to obtain the desired values.
122
退 滿退
To find each planet's fixed conjunction and visibility-and-concealment general-use accumulation: for Jupiter, Mars, and Saturn, use the mean-conjunction and prior-swift and posterior-concealment fixed accumulations as the general-use accumulation; for Venus and Mercury at mean-conjunction, evening appearance, and morning concealment, set the segment's excess-deficit difference (double for Venus, triple for Mercury) in the upper row; Set the excess-deficit difference again, multiply by that segment's first-motion rate, retreat two places, and subtract from the upper row; Set the first-motion rate, subtract one hundred parts, divide by the remainder for days with the remainder as parts, then subtract when in excess and add when in deficit to the middle accumulation, and obtain that star and variation's general-use accumulation.
123
For Venus and Mercury at second conjunction, evening concealment, and morning appearance, set the segment's excess-deficit difference (use directly for Venus, double for Mercury), advance two places, add one hundred parts to the first-motion rate and divide, combine with the excess-deficit difference, add or subtract to the middle accumulation according to excess or deficit, and obtain that star and segment's general-use accumulation.
124
滿滿
To find each planet's fixed-conjunction fixed accumulation and fixed star: for Jupiter, Mars, and Saturn at mean-conjunction, subtract one hundred parts from the mean-conjunction first-day motion parts, use the remainder to reduce that day's solar excess-deficit into parts, convert hundreds of parts to days with the remainder as parts, and name the result the distance-from-conjunction difference day; Subtract the excess-deficit parts to obtain the distance-from-conjunction difference degree; Apply the difference day and difference degree to the mean-conjunction general-use accumulation, adding when in deficit and subtracting when in excess, to obtain that star's fixed-conjunction day, fixed accumulation, and fixed star. For Venus and Mercury at mean-conjunction, subtract one hundred parts from the first-day motion parts, divide that day's solar excess-deficit parts by the remainder, and obtain the distance-from-conjunction difference day; Add the excess-deficit parts to obtain the distance-from-conjunction difference degree; Apply the difference day and difference degree to the mean-conjunction general-use accumulation, adding when in excess and subtracting when in deficit, to obtain that star's fixed-conjunction day, fixed accumulation, and fixed star.
125
退 宿宿
For Venus and Mercury in retrograde conjunction, add one hundred parts to the first-day motion parts, divide the solar excess-deficit parts by the sum, and obtain the distance-from-conjunction difference day; Subtract the distance-from-conjunction difference day from the excess-deficit parts to obtain the distance-from-conjunction difference degree; Apply the difference day to the second-conjunction general-use accumulation, subtracting when in excess and adding when in deficit, to obtain that star's second-conjunction fixed day, fixed accumulation, and difference degree; Add when in excess and subtract when in deficit to the second-conjunction general-use accumulation to obtain that star's second-conjunction fixed day and fixed star; Add the winter solstice major and minor remainders for each case and assign lodges from the ecliptic hour-of-addition solar position to obtain that day's date, time, and lodge sequence.
126
To find Jupiter, Mars, and Saturn morning appearance and evening concealment fixed-use accumulation: set each star's segment general-use accumulation, then add or subtract one-quadrant degree — add for morning appearance and subtract for evening concealment.
127
滿 滿退
If at or below half circuit-of-heaven, square the value; if above, subtract from circuit-of-heaven degrees and square the remainder; double and hundred-reduce each; if at or above 167 subtract one hundred of that day's solar excess-deficit parts, otherwise add; multiply by that star's base heliacal visibility degree, divide by fifteen, and obtain the difference; Then subtract one hundred parts from that segment's first-day motion parts, divide the difference by the remainder for days with the remainder as parts, and add or subtract the result from the general-use accumulation — add for morning appearance and subtract for evening concealment.
128
Each then yields that star's morning appearance and evening concealment fixed-use accumulation; Add the civil new-year winter solstice major remainder, count from jiazi, outside the count, and obtain the day and time.
129
To find Venus and Mercury evening appearance and morning concealment fixed-use accumulation: set each star's segment general-use accumulation, then add or subtract one-quadrant degree — subtract for evening appearance and add for morning concealment.
130
滿滿
If at or below half circuit-of-heaven, square the value; if above, subtract from circuit-of-heaven degrees and square the remainder; double and hundred-reduce; if at or above 167 subtract one hundred of the solar excess-deficit parts, otherwise add; multiply by that star's base heliacal visibility degree, divide by fifteen, and obtain the difference; Then subtract one hundred parts from that segment's first-day motion parts, divide the difference by the remainder for days with the remainder as parts, and add or subtract the result from the general-use accumulation — add for evening appearance and subtract for morning concealment.
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