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卷八十 志第三十三 律曆十三

Volume 80 Treatises 33: Measures and Calendar 13

Chapter 80 of 宋史 · History of Song
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1
The Jiyuan Calendar
2
Procedure for Lunar Nodes and Conjunctions
3
Convergence termination parts: 198,377; seconds 880.
4
Convergence termination period: 27 days, remainder 1,547 parts, seconds 880.
5
Convergence middle period: 13 days, remainder 4,418 parts, seconds 5,440.
6
New-moon difference: 2 days, remainder 2,320 parts, seconds 9,120.
7
Full-moon stride: 14 days, remainder 5,579 parts.
8
For the above constants, the seconds denominator is 10,000.
9
The convergence ratio is 324.
10
The convergence number is 4,127.
11
Convergence termination arc: 363°79′44″ (approximate parts).
12
Convergence middle arc: 181°89′72″ (approximate parts).
13
Convergence image arc: 90°94′86″ (approximate parts).
14
Half convergence image arc: 45°47′43″ (approximate parts).
15
Solar eclipse yang-calendar limit: 3,400; fixing divisor 340.
16
Lunar eclipse yin-calendar limit: 4,300; fixing divisor 430.
17
Lunar eclipse limit: 6,800; fixing divisor 440.
18
For the limits above, the parts-and-seconds denominators are each 100.
19
滿滿
To find the eleventh civil month's mean new-moon hour of entry into convergence: set the accumulated parts for that syzygy's hour, cast out full convergence termination parts and seconds, convert the remainder through the day divisor into days and remainder-seconds, and obtain the general convergence day and remainder-seconds for the eleventh month's mean new moon.
20
滿
To find the next new and full moon entry into convergence: set the eleventh-month mean new-moon hour general convergence day and remainder-seconds; for the next new moon, add the new-moon difference; for the full moon add the full-moon stride; cast out full convergence termination days and remainder-seconds to obtain each next new or full moon hour general convergence day and remainder-seconds. Subtracting each mean syzygy's minor remainder yields the midnight general convergence day and remainder-seconds for that new or full moon.
21
退退
To find fixed syzygy midnight convergence entry: start from mean midnight general convergence day and remainder-seconds; if the fixed syzygy's day-period advances or retreats, adjust the convergence day likewise, otherwise take the mean value as fixed.
22
滿
For the next fixed new-moon midnight entry: from each fixed new-moon midnight general convergence day and remainder-seconds, add two days in a long month and one in a short month, and always add 5,742 seconds 9,120 to the remainder for the next new moon's midnight entry; to advance day by day, add one day cumulatively, cast out full convergence termination days and remainder-seconds, and obtain each midnight general convergence day and remainder-seconds.
23
To find fixed syzygy hour-of-addition convergence entry: set mean syzygy hour general convergence day and remainder-seconds, apply entry-into-qi and entry-into-rotation tiao–chuo fixed numbers (tiao subtract, chuo add), and obtain fixed syzygy hour general convergence day and remainder-seconds.
24
滿退
To find fixed syzygy hour moon convergence accumulated degrees: convert the general convergence day through the day divisor with the remainder, shift one place, divide by 5,453 for degrees, reduce the remainder to parts, and obtain the hour moon's convergence accumulated degrees and parts. For each midnight, follow this procedure.
25
滿退
To find fixed syzygy hour moon fixed convergence accumulated degrees: set hour convergence accumulated degrees and parts, apply hour entry-into-rotation slow-fast degree (slow subtract, fast add), and advance or retreat convergence termination degrees and parts as needed.
26
That yields the fixed syzygy hour moon's fixed convergence accumulated degrees and parts. For each midnight, follow this procedure.
27
To find fixed syzygy hour yang/yin calendar accumulated degrees: set fixed hour moon fixed convergence accumulated degrees and parts; at or below convergence middle counts as yang-calendar accumulated degrees; if above, subtract convergence middle; the remainder is yin-calendar accumulated degrees. For each midnight, follow this procedure.
28
滿滿退
To find fixed syzygy hour lunar ecliptic latitude: inspect entered yin- or yang-calendar accumulated degrees and parts; at or below the convergence image counts as the young image; if above, cover and subtract convergence middle; the remainder is entry into the old image. Set entered young or old image degrees above and convergence image degrees below, subtract and multiply (divide by 500), subtract from entered image degrees, then subtract and multiply against convergence middle (divide by 1,375), reduce to parts, and obtain fixed syzygy hour lunar ecliptic latitude in degrees and parts. For each midnight, follow this procedure.
29
滿退
To find syzygy hour general convergence day: set the month's mean syzygy hour general convergence day and remainder-seconds, apply entry-into-qi tiao–chuo fixed number (tiao subtract, chuo add), adjust the day as needed, and obtain syzygy hour general convergence day and remainder-seconds. Near the start of convergence counts as convergence beginning; days twenty-six or twenty-seven are convergence beginning; near convergence middle counts as convergence middle; days thirteen or fourteen are convergence middle.
30
To find eclipse greatest fixed number: combine that syzygy's entry-into-qi and entry-into-rotation tiao–chuo fixed numbers (same name together, different name cancel) and set aside as auxiliary; multiply auxiliary by fixed syzygy hour entry-into-rotation count-outside damage-benefit rate and divide by the day divisor; if fixed syzygy is count-outside on days four–seven and remainder is at or below the initial number, multiply by the initial rate and divide by the initial number; if above the initial number, multiply by the final rate and divide by the final number.
31
滿退
Apply the result according to entry-into-rotation: for chuo follow damage-benefit; for tiao benefit-subtract and damage-add to the auxiliary; apply tiao subtract and chuo add to the mean syzygy minor remainder to obtain the general remainder. Advance or retreat the major remainder when the sum overflows or falls short.
32
滿
For solar eclipse, if the general remainder is at or below the half method, it is before middle; array the half method below, subtract and multiply (divide by 10,935), and obtain the difference; subtract the difference from the general remainder to obtain the eclipse-greatest fixed remainder; subtracting the half method yields the before-noon fraction. if the general remainder is at or above the half method, subtract the half method for after middle; Place the half method in the lower row of the array. subtract below from above, multiply and divide by the day divisor, and obtain the difference; add the difference to the general remainder to obtain the eclipse-greatest fixed remainder; then subtract the half method to obtain the after-noon fraction. For lunar eclipse, if general remainder is at or above half method subtract half method; square remainder if ≤1,822.5, otherwise cover-subtract half method and square, divide by 30,000, and subtract from general remainder for eclipse-greatest fixed remainder; If general remainder is below half method and within two-thirds of sunrise part, array above; if above, adjust against sunrise part, double, array, reduce sunrise part by 4/3, subtract and multiply (divide by 15,000), and add to general remainder for eclipse-greatest fixed remainder.
33
滿滿
To find eclipse-greatest watch and quarter: double the fixed remainder, divide by watch divisor for watches, convert remainder to quarters (multiply by five, divide by quarter divisor), and obtain parts. Count watches from zi-zheng, outside the count, to obtain eclipse-greatest watch, quarter, and parts. If adding half a watch, count from zi-initial.
34
To find eclipse-greatest entry into qi: combine eclipse-greatest major and minor remainders with eclipse-fixed minor remainder and fixed syzygy major remainder, and compare with mean syzygy major and minor remainders.
35
Set syzygy eclipse-greatest major and minor remainders, subtract mean syzygy remainders, and add or subtract mean syzygy entry-into-qi day remainder according to whether mean syzygy is less or more.
36
退
That yields solar or lunar eclipse-greatest entry-into-qi day and remainder-seconds. For each eclipse-greatest entry into qi and remainder-seconds, add qi middle accumulation, convert remainder through day divisor into parts, and obtain eclipse-greatest middle accumulation and parts.
37
To find eclipse-greatest daily motion accumulated degrees: multiply eclipse-greatest entry-into-qi remainder by that qi day's excess-deficit parts (divide by day divisor), add or subtract day's before-after number (add after day, subtract after parts).
38
Apply add-then-subtract to eclipse-greatest middle accumulation to obtain eclipse-greatest daily-motion accumulated degrees and parts.
39
滿 滿
To find qi difference: set solar eclipse-greatest daily-motion accumulated degrees and parts, cast out two solstice limit, and if remainder is at or below image limit it is initial; if above, cover and subtract two solstice limit; the remainder is final. Square each case, shift two places, divide by 343, subtract from 2,430, and obtain qi difference; multiply qi difference by the before- or after-noon part. Divide by half day-part, subtract from qi difference, and obtain qi-difference fixed number. After winter solstice in final limit and after summer solstice in initial limit: subtract at convergence beginning, add at convergence middle.
40
After summer solstice in final limit and after winter solstice in initial limit: add at convergence beginning, subtract at convergence middle.
41
Divide by half day-part; if result meets or exceeds qi difference, cover-subtract qi difference and invert add/subtract as required.
42
滿滿
To find quarter difference: set solar eclipse-greatest daily-motion accumulated degrees and parts, cast out two solstice limit, subtract and multiply against limit (divide by 343), and obtain quarter difference. Multiply quarter difference by before- or after-noon part, double, divide by half method, and obtain quarter-difference fixed number. After winter solstice with eclipse-greatest before noon, or after summer solstice after noon: add at convergence beginning, subtract at convergence middle.
43
After winter solstice with eclipse-greatest after noon, or after summer solstice before noon: subtract at convergence beginning, add at convergence middle.
44
Divide by half method; if result meets or exceeds quarter difference, double quarter difference and subtract accordingly; apply add/subtract to obtain quarter-difference fixed number.
45
To find fixed new-moon convergence fixed day: set new-moon general convergence day and remainder-seconds, apply qi- and quarter-difference fixed numbers, add 3,100 at convergence beginning and subtract 3,000 at convergence middle, and obtain new-moon fixed convergence day and remainder-seconds.
46
滿退
To find fixed full-moon convergence fixed day: set full-moon entry-into-rotation tiao–chuo fixed number, multiply by convergence ratio (divide by convergence number), apply tiao subtract and chuo add to general convergence remainder, adjust day as needed, and obtain full-moon fixed convergence day and remainder-seconds.
47
To find moon yang/yin calendar entry: if fixed syzygy convergence fixed day and remainder-seconds are at or below middle day and remainder-seconds, the moon is in the yang calendar; if at or above middle day and remainder-seconds, subtract middle day; the moon is in the yin calendar.
48
滿
To find eclipse-limit before- and after-convergence parts: inspect fixed syzygy moon yang/yin calendar entry; remainder below one day is after-convergence part; if within about thirteen days, cover and subtract convergence middle day for before-convergence part; if each before- and after-convergence part is at or below the eclipse limit, the syzygy has entered the eclipse limit.
49
退
To find solar eclipse magnitude: subtract yin/yang calendar eclipse limit from each before- and after-convergence part, divide remainder by fixed divisor, and obtain solar eclipse major part; reduce any remainder to minor parts. Take the major part on a scale of ten to obtain solar eclipse magnitude. If magnitude falls short of a major part, the path is near the node and light is only faintly dimmed; an eclipse may or may not occur that day.
50
退
To find lunar eclipse magnitude: if full-moon before- and after-convergence parts are at or below 2,400, the eclipse is total; if above, subtract from eclipse limit, divide remainder by fixed divisor, and obtain lunar eclipse major part; reduce any remainder to minor parts. Take the major part on a scale of ten to obtain lunar eclipse magnitude.
51
退
To find solar eclipse general use-parts: square before- and after-convergence parts (shift two places), divide by 198 (yang) or 317 (yin), subtract from 583, and obtain solar eclipse general use-part.
52
退
To find lunar eclipse general use-parts: square before- and after-convergence parts (shift two places), divide by 704, subtract from 656, and obtain lunar eclipse general use-part.
53
To find eclipse fixed use-parts: set general use-part as auxiliary, multiply by eclipse-greatest hour entry-into-rotation count-outside damage-benefit rate (divide by day divisor), and on days four or seven apply eclipse-fixed remainder rule.
54
Apply result according to entry-into-rotation (chuo: follow damage-benefit; tiao: benefit-subtract, damage-add to auxiliary) to obtain solar and lunar eclipse fixed use-part.
55
退
To find lunar eclipse total inner and outer parts: square lunar eclipse before- and after-convergence parts (shift two places), divide by 249, subtract from 231, multiply remainder by fixed use-part (divide by general use-part), and obtain lunar eclipse total inner part; Subtract the total inner part from the fixed use-part to obtain the total outer part.
56
滿 滿
To find eclipse first diminishment, restoration fullness, and minor remainders: set sun and moon eclipse-greatest minor remainders, subtract the fixed use-part from each, and obtain first diminishment; Add the fixed use-part to obtain restoration fullness; For a total lunar eclipse, subtract the total inner part to obtain first totality; Add again to obtain light generation; each case then yields the required minor remainders. To find clock time, apply the eclipse-greatest procedure.
57
To find lunar eclipse watch and point: double the day's dawn parts at eclipse greatest, subtract 729, and five-reduce the remainder to obtain the watch method; Divide again by five to obtain the point method.
58
滿
To find lunar eclipse watch and point entry: set first diminishment, greatest eclipse, and restoration-end minor remainders; below dawn parts add dawn parts, above dusk parts subtract dusk parts; divide the remainder by the watch method for watch count, then by the point method for point count. Name from the first watch outside the count to obtain each entered watch and point.
59
西 西 西
To find solar eclipse direction of first contact: with the sun in the yang half, first contact is southwest, maximum due south, and recovery southeast; With the sun in the yin half, first contact is northwest, maximum due north, and recovery northeast. 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 (noon location).
60
西 西 西
To find lunar eclipse direction of first contact: with the moon in the yang half, first contact is northeast, maximum due north, and recovery northwest; With the moon in the yin half, first contact is southeast, maximum due south, and recovery southwest. 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.
61
滿 退 退
To find the visible fraction when an eclipse is caught at sunrise or sunset: subtract rise or set parts from eclipse-greatest minor remainder to obtain the horizon-partial difference; Multiply by the eclipsed fraction and divide by the fixed use-part; for total lunar eclipse, subtract the total inner part from the horizon-partial difference, advance the remainder one place, divide by the total outer part, subtract the result from the totality fraction to obtain the moon's visible fraction at rise or set; if subtraction cannot be completed, the eclipse is partially total at rise or set. Subtract the result from the eclipsed fraction to obtain the visible fraction at rise or set for sun or moon with horizon partial eclipse. If greatest eclipse is in daylight, at dawn the eclipse is still advancing and at dusk it has already retreated; If greatest eclipse is at night, at dawn it has already retreated and at dusk it is still advancing.
62
宿
To find eclipse-greatest lodge position: set daily-motion accumulated degrees at eclipse greatest; at full moon add half a circuit of heaven.
63
宿
Add to the winter solstice ecliptic solar degree at hour-of-addition, name the lodges, and obtain sun and moon eclipse-greatest lodge degrees and parts.
64
Step Five Planets
65
Jupiter circuit rate: 2,907,879, 64 seconds.
66
Circuit difference: 245,253, 64 seconds.
67
Calendar rate: 2,662,636, 22 seconds.
68
Circuit day: 398, 88 approximate parts, 60 seconds.
69
Calendar degree: 365, 24 approximate parts, 50 seconds.
70
Calendar mid-degree: 185, 62 approximate parts, 25 seconds.
71
Calendar stride degree: 15, 21 approximate parts, 85 seconds.
72
Heliacal setting visibility: 13 degrees.
73
Jupiter excess-deficit calendar
74
Mars circuit rate: 5,685,687, 64 seconds.
75
Circuit difference: 360,414, 44 seconds.
76
Calendar rate: 2,662,647, 20 seconds.
77
Circuit day: 779, 92 approximate parts, 97 seconds.
78
Calendar degree: 365, 24 approximate parts, 65 seconds.
79
Calendar mid-degree: 182, 62 approximate parts, 32½ seconds.
80
Calendar stride degree: 25, 21 approximate parts, 86 seconds.
81
Heliacal setting visibility: 19 degrees.
82
Mars excess-deficit calendar
83
Saturn circuit rate: 2,756,288, 78 seconds.
84
Circuit difference: 93,662, 78 seconds.
85
Calendar rate: 2,669,925, 90 seconds.
86
Circuit day: 378, 9 approximate parts, 17 seconds.
87
Calendar degree: 366, 24 approximate parts, 49 seconds.
88
Calendar mid-degree: 183, 12 approximate parts, 24½ seconds.
89
Calendar stride degree: 15, 26 approximate parts, 2 seconds.
90
Heliacal setting visibility: 17 degrees.
91
Saturn excess-deficit calendar
92
Venus circuit rate: 4,256,651, 43½ seconds.
93
Conjunction day: 291, 95 approximate parts, 14 seconds.
94
Calendar rate: 2,662,696, 16 seconds.
95
Circuit day: 583, 90 approximate parts, 28 seconds.
96
Calendar degree: 365, 25 approximate parts, 32 seconds.
97
Calendar mid-degree: 182, 62 approximate parts, 66 seconds.
98
Calendar stride degree: 15, 21 approximate parts, 89 seconds.
99
Heliacal setting visibility: 10½ degrees.
100
Venus excess-deficit calendar
101
HT5SS
Mercury circuit rate: 844,738, 5 seconds.
102
Conjunction day: 57, 93 approximate parts, 81 seconds.
103
Calendar rate: 2,662,794, 95 seconds.
104
Circuit day: 115, 87 approximate parts, 62 seconds.
105
Calendar degree: 365, 26 approximate parts, 68 seconds.
106
Calendar mid-degree: 182, 63 approximate parts, 34 seconds.
107
Calendar stride degree: 15, 21 approximate parts, 94½ seconds.
108
Morning hidden, evening visible: 14 degrees.
109
Evening hidden, morning visible: 19 degrees.
110
Mercury excess-deficit calendar
111
滿滿退 退
To find each planet's mean conjunction after civil new-year winter solstice and the central accumulation and central star for every segment: set the qi accumulated parts, divide each by that star's circuit rate, and obtain the circuit count. The remainder is the anterior conjunction. Subtract from the circuit rate; convert the remainder to days by the day divisor, reduce the remainder to parts and seconds, and obtain that star's mean-conjunction central accumulation after civil new-year winter solstice; Name the result the mean-conjunction central star; add each segment's standard days and degrees cumulatively to obtain every segment's central accumulation and central star. For retrograde segments, subtract the standard degree to obtain the segment's central star.
112
To find mean-conjunction entry into the calendar cycle for Jupiter, Mars, and Saturn and each segment: set that star's circuit count, and for post-winter-solstice conjunction add one to the count.
113
滿滿滿退
Multiply by the circuit difference, cast out full calendar rates, convert the remainder to degrees by the day divisor, reduce the remainder to parts and seconds, and obtain the star's mean-conjunction entry-into-calendar degree and parts and seconds. Add each segment's limit degree cumulatively in order to obtain every segment's entry into the calendar cycle.
114
滿滿退
To find Venus and Mercury mean conjunction and each segment's entry into the calendar cycle: set the qi accumulated parts, cast out full calendar rates for each star, convert the remainder to degrees and parts and seconds, add to the mean-conjunction central star, and obtain mean-conjunction entry-into-calendar degree and parts and seconds after civil new-year winter solstice; Add that star's segment limit degrees cumulatively in order to obtain every segment's entry into the calendar cycle.
115
滿
To find each planet's mean conjunction and every segment's excess-and-deficit fixed difference: set each star and segment's entry-into-calendar degree and parts; at or below the calendar mid counts as excess; If above the calendar mid, subtract it; the remainder is in deficit. Divide by that star's calendar stride to obtain the stride count; the remainder is entry-into-stride degree and parts; Name from outside the stride count, multiply the tabulated loss-and-gain rate for that stride, divide by the calendar stride for parts, and convert parts filling 100 to degrees; Apply it to the underlying excess-and-deficit accumulation to obtain that star and segment's excess-and-deficit fixed difference.
116
To find each planet's mean conjunction and every segment's fixed accumulation: set each star and segment's central accumulation, add or subtract the segment's excess-and-deficit fixed difference according to excess or deficit, and obtain the segment's fixed-accumulation days and parts; Add the civil new-year winter solstice greater remainder and approximate parts to obtain the fixed day and parts; Cast out full era rules of 60, name from jimao outside the count, and obtain the day and double-hour.
117
滿
To find the month and day for each planet's mean-conjunction segments: set each segment's fixed accumulation, add civil new-year intercalary days and approximate parts, divide by the new-moon policy and approximate parts for month count, and take the remainder as days and parts elapsed within the month. Name the month count from civil new-year month eleven outside the count to obtain the segment's days and parts since mean new moon, and take the day-and-double-hour interval as the fixed new-moon month and day.
118
To find each planet's mean conjunction and every segment's hour-of-addition fixed star: set each segment's central star, apply the segment's excess-and-deficit fixed difference (double for Venus, triple for Mercury), then add or subtract according to excess or deficit.
119
宿
That yields each planet's segment fixed star; Add to the winter solstice ecliptic solar degree at hour-of-addition, name the lodges, and obtain that star and segment's hour-of-addition lodge degree, parts, and seconds. For all five planets, the anterior station fixes the first-day star of the anterior segment and the posterior station the first-day star of the posterior segment; compute the remainder by the procedure.
120
退
To find each planet's first-day before-dawn midnight fixed star for every segment: multiply the segment's initial motion rate by its hour-of-addition parts and hundred-reduce, then subtract for direct motion or add for retrograde from that day's hour-of-addition fixed star to obtain the segment's first-day before-dawn midnight fixed star; Add and name as before to obtain the result.
121
To find each segment's day rate and degree rate: for each take the day-and-double-hour interval from that segment to the next segment as the segment's day rate; Subtract that segment's midnight fixed star from the next segment's midnight fixed star to obtain the segment's degree rate, parts, and seconds.
122
To find each segment's parallel degree: set each segment's degree rate, parts, and seconds, divide by its day rate, and obtain the segment's parallel degree, parts, and seconds.
123
退 退
To find each segment's total difference: subtract each segment's parallel parts from the next segment's parallel parts; the remainder is the general difference; Add the previous segment's general difference, multiply by four, and shift one decimal place to obtain the total difference. When the prior segment lacks parallel parts for subtraction, subtract that segment's parallel parts from the next segment's first-day motion parts; the remainder is half the total difference; Double it to obtain the total difference. When the following segment lacks parallel parts for subtraction, subtract that segment's parallel parts from the previous segment's last-day motion parts; double the half-total difference to obtain the total difference. For the morning-slow final segment, when parallel parts are absent, subtract its parallel parts from the previous initial segment's last-day motion parts to obtain half the total difference; For retrograde segments, set each segment's parallel parts, multiply by fourteen and divide by fifteen to obtain the total difference. For Mercury, apply the direct-segment procedure to obtain the result. For the evening-slow initial segment, when the prior segment lacks parallel parts, subtract its parallel parts from the next final segment's first-day motion parts to obtain half the total difference.
124
退
To find each segment's first- and last-day motion parts: halve the segment's total difference and add or subtract its parallel parts; when the next segment's parallel parts are greater, subtract for the first day and add for the last; When the next segment's parallel parts are fewer, add for the first day and subtract for the last. In retrograde motion, subtract for the first day and add for the last; for the following segment, add for the first day and subtract for the last.
125
滿
Each yields that star's first- and last-day motion degrees, parts, and seconds for the segment. When both adjacent segments' parallel parts are greater or both are fewer, distribute evenly; When a segment's total difference is less than one major part, distribute evenly as well.
126
宿
To find the lodge position at each day's before-dawn midnight: set the segment's total difference, divide by the day rate minus one, and obtain the day difference; Adjust the first-day motion parts cumulatively; when later motion parts decrease, subtract; when later motion parts increase, add.
127
退宿宿
This yields each day's motion in degrees, parts, and seconds; For direct motion add and for retrograde subtract from the segment's first-day lodge at before-dawn midnight, naming each in turn to obtain the lodge at every day's before-dawn midnight.
128
宿
To find a given day's lodge directly: take the requested day minus one, halve it, multiply by the day difference and add or subtract from the initial motion parts; subtract when later motion parts are fewer; add when later motion parts are greater.
129
退宿宿
Multiply by the requested day to obtain accumulated degrees; Add for direct motion or subtract for retrograde from the segment's first-day lodge to obtain the lodge for the requested day.
130
滿
To find each planet's mean conjunction and appearance or occultation entry into a qi period: set the fixed accumulation, divide by the qi policy and approximate parts for the qi count, and take the remainder as days, parts, and seconds since qi entry. Count the qi from civil new-year winter solstice to obtain each planet's mean conjunction and appearance or hiding qi-entry day, parts, and seconds. When the fixed accumulation exceeds a full year's circuit, discard the excess; the remainder falls after the following year's winter solstice.
131
退
To find motion difference at conjunction, appearance, or occultation: for Jupiter, Mars, and Saturn, subtract the sun's motion parts from the segment's first-day planetary motion parts. For Venus and Mercury in direct motion, subtract the planet's motion parts from the sun's motion parts on the segment's first day. For Venus and Mercury in retrograde motion, add the planet's and sun's motion parts on the segment's first day.
132
便 滿退 退
To find fixed conjunction and appearance or occultation general accumulations: for Jupiter, Mars, and Saturn, use the mean-conjunction morning-swift and evening-hidden fixed accumulations directly as the fixed conjunction, appearance, and occultation general accumulations. For Venus and Mercury, set each segment's excess-and-deficit fixed difference (double for Mercury), divide by the segment's motion difference for days and convert the remainder to parts and seconds; at mean conjunction evening-swift and morning-hidden, subtract excess or add deficit to the fixed accumulation; At retrograde conjunction evening-hidden and morning-appearance, add excess or subtract deficit from the fixed accumulation for the fixed conjunction, appearance, and occultation general accumulations.
133
退退 滿 宿宿
To find fixed conjunction accumulation and fixed star: for Jupiter, Mars, and Saturn, divide the day-prior-and-posterior count by mean-conjunction motion difference to obtain the conjunction-interval difference in days; subtract the prior-and-posterior count to obtain the conjunction-interval difference in degrees; Add the difference day and degree posteriorly and subtract anteriorly from the planet's fixed-conjunction general accumulation to obtain fixed-conjunction day, accumulation, and star. For Venus and Mercury in direct conjunction, divide the day-prior-and-posterior count by mean-conjunction motion difference for conjunction-interval difference days; add the prior-and-posterior count for conjunction-interval difference degrees; Add difference day and degree anteriorly and subtract posteriorly from the planet's fixed-conjunction general accumulation. For Venus and Mercury in retrograde conjunction, divide the day-prior-and-posterior count by retrograde-conjunction motion difference; subtract the prior-and-posterior count for conjunction-interval difference degrees; Subtract then add the difference day and add then subtract the difference degree from the re-fixed-conjunction general accumulation to obtain re-fixed conjunction accumulation and star. Add winter solstice great remainder and approximate parts to each fixed accumulation, cast out full era cycles, count from jimao, and obtain the fixed-conjunction day and double-hour; Add the fixed star to the winter solstice ecliptic solar degree at hour-of-addition and name the lodges to obtain the fixed conjunction's lodge position.
134
滿退
To find fixed appearance and occultation days for Jupiter, Mars, and Saturn: set each planet's general accumulation, add for morning appearances and subtract for evening occultations according to the image limit, apply the two-solstice limit formula, multiply by visibility degree and divide by fifteen for the difference; Convert the difference to days at the segment's motion difference rate, remainder to parts and seconds, add for appearance and subtract for occultation from the general accumulation; Name as before to obtain the day and double-hour.
135
To find fixed appearance and occultation days for Venus and Mercury: for evening appearance and morning occultation, divide the day-prior-and-posterior count by motion difference; add anteriorly and subtract posteriorly from the general-use accumulation for the regular-use accumulation. for morning appearance and evening occultation, divide by motion difference for days; subtract anteriorly and add posteriorly from the general-use accumulation. If the regular-use accumulation is at or below the two-solstice limit, count it as after winter solstice; if above, subtract the limit; the remainder is after summer solstice. For days and parts after a solstice, self-multiply if at or below the image limit, otherwise subtract from the two-solstice limit and self-multiply the remainder; divide per the method for parts; After winter solstice for morning, after summer solstice for evening, use eighteen as divisor; After winter solstice for evening, after summer solstice for morning, use seventy-five as divisor.
136
滿滿退
multiply by the occultation-appearance degree and divide by fifteen for the difference; When full divide by motion difference for days, remainder to parts and seconds, add or subtract from regular-use accumulation for fixed-use accumulation; Name as before to obtain fixed appearance and occultation day and double-hour. After winter solstice, add for morning appearance and evening occultation, subtract for evening appearance and morning occultation; After summer solstice, subtract for morning appearance and evening occultation, add for evening appearance and morning occultation.
137
For Mercury, when evening-swift falls from the start of Great Heat qi through day nine and thirty-five parts of Lesser Snow qi, it is invisible; When morning-station falls from the start of Great Cold qi through day nine and thirty-five parts of Start of Summer qi, Mercury does not appear in the morning in spring or in the evening in autumn.
138
便
In the sixth month of the sixth year of Xining, Chen Yi, supervisor of the Directorate of Astronomy, reported: "The armillary sphere's measurements do not agree with the Essentials of Methods. The two poles and the equator's four quarters are uneven, the distance graduations on the rings do not match left and right, the sighting arm is too heavy to turn smoothly, the ecliptic band is blocked by the crossbeam, the touring sight-ring is cracked, the ecliptic fails to align with the heavens, and the pole star within the celestial pivot cannot be seen. The Astronomical Bureau's armillary sphere likewise has uneven scales on the two poles and equator, while the ecliptic, celestial constant ring, and lunar path block the crossbeam; the lunar path fails to match the heavens, the celestial constant ring binds and turns with difficulty, and the pole star within the celestial pivot remains unseen. Everything should be refurbished from the old instrument and recast as a new armillary sphere using ancient foot-lengths, with lodge degrees evenly marked, rings made light and easy to move, the ecliptic and equator and celestial constant ring set on edge with the northern rim aligned to celestial degree, the lunar path removed so it no longer blocks the crossbeam, the celestial pivot widened to two and a half degrees to take in the pole star, and pivots added to the rings and poles so the sighting arm may travel freely. An edict ordered manufacture in the new design and placement at the Directorate of Astronomy for trial, to compare coarse and fine readings. In the sixth month of the seventh year, the Directorate presented the new armillary sphere and clepsydra at the Gate Facing the Sun. The emperor summoned his chief ministers to inspect them and questioned Shen Kuo, co-supervisor of the project, again and again; Kuo explained in full the rationale behind every change. They soon reported further: "As the edict directed, directorate officers were gathered to compare the old and new instruments for accuracy, but no valid comparison could be made." An edict then ordered the instruments installed in the Hanlin Astronomical Bureau. In the seventh month Shen Kuo was appointed Right Remonstrator, and Huangfu Yu, Autumn Office Director of the Directorate, among others received graded rewards. Earlier Kuo had submitted three memorials on the armillary sphere, clepsydra, and gnomon table, recorded in the Astronomical Treatise. The court adopted his proposals and ordered the refashioning of ritual instruments and calendrical books. Now that the armillary sphere and clepsydra were finished, rewards were granted accordingly.
139
In the first month of the fifth year of Yuanfeng, Academician-Expositor Wang Anli reported: "Ouyang Fa, officer charged with determining the armillary sphere, has submitted wooden models of the armillary sphere and clepsydra that show what the new instruments should do and remedy what the old ones got wrong. We find the Directorate's clepsydra coarse and unreliable and ask that it be rebuilt to the new design. The Zhidao and Huangyou armillary spheres and gnomon tables are likewise defective; we ask that they be corrected and reported to the throne as the regulations provide." The court approved. In the third month of the fourth year of Yuanyou, Academician-Expositor Xu Jiang and others reported: "The office determining the Yuanyou armillary sphere and celestial globe, having first been ordered to build a water-driven wooden model — with bronze to follow if observations showed no error — has now verified that every reading agrees with the sky." An edict ordered casting in bronze, retaining the name Yuanyou Armillary Sphere and Celestial Globe. Jiang and his colleagues added: "The instrument once called the armillary sphere has a round outer shell on which star degrees may be marked all around; inside are the ji and heng sighting components by which one peers up at the heavens. The instruments now built split these into two: the armillary sphere measures true celestial degrees, while a celestial globe is placed in a sealed chamber and driven to revolve like the sky, coordinated with the sphere. If combined in one, the globe would serve as the sphere and share the same corrected celestial degrees — and the armillary sphere and celestial globe would be won in a single instrument. We ask that a unified armillary-heaven instrument be made anew." The court agreed; in the fourth month of the seventh year an edict ordered Left Vice Director of the Secretariat Su Song to compose the inscription for the Armillary Sphere and Celestial Globe. In the sixth month the Yuanyou Armillary Sphere and Celestial Globe were completed, and officials of the Three Departments and Privy Council were summoned to inspect them. In the tenth month of the first year of Shaosheng, an edict ordered the Ministry of Rites and the Secretariat, at the office manufacturing the armillary sphere and celestial globe, to have bureau officers test old and new armillary spheres together and report whichever proved precise and fit for use.
140
In the seventh month of the sixth year of Xuanhe, Chief Councillor Wang Fu reported:
141
宿 西西 西
In the first year of Chongning I met by chance at the capital a man from beyond the ordinary world who gave his surname as Wang and handed me an unadorned book describing the mechanism of the ji and heng in meticulous detail. I had the Service-for-the-Emperor Office build a small model to test it; after more than two months the xuanji was finished, round as a pellet and marked with three hundred sixty-five and a quarter degrees, bearing the south and north poles, Mount Kunlun, and the yellow and red paths, with the twenty-four qi, seventy-two hou, sixty-four hexagrams, ten stems, twelve branches, the hundred day-and-night marks, the twenty-eight lodges, and the inner and outer three enclosures with every star of the circuit of heaven. The sun and moon travel along the ecliptic's daily course: each day the sky wheels left one full turn while the sun wheels right one degree; at winter solstice it emerges twenty-four degrees south of the equator, at summer solstice it enters twenty-four degrees north, and at the spring and autumn equinoxes the yellow and red paths cross so it emerges at mao and sets at you. The moon moves more than thirteen degrees a day; its light is born in the west, first shaped like a hook with the lower arc — a half-disk seen in the west — until at full it is round; after full the western arc is cut away in the lower ring while the eastern half-disk appears, until at last it vanishes. When a star first appears, when it culminates, when it is about to set — whether to left or right, slow or fast — everything matches the sky without the slightest error. The jade balance stands outside the screen, gripping the pivot's dipper; water is poured to drive the wheel beneath, where forty-three gear trains mesh by interlocking keys and turn in sequence without human hand — the fastest wheel runs two thousand nine hundred twenty-eight teeth a day, the slowest one tooth in five days; so wide the spread of speeds, yet all born of a single engine, its fineness nearly that of the Maker himself. Everything else follows the system of Tang Yixing.
142
使
Yet Yixing's old mechanism relied entirely on copper and iron, which when stiff would not turn of themselves; the present design substitutes hard wood or fine jade and the like. The old design bound two outer wheels to carry sun and moon, and those wheels blocked and eclipsed star degrees so that looking up at the lodges' sequence was unclear; the new design fixes both sun and moon to the ecliptic, like ants crawling on a millstone rim. The old mechanism could mark conjunction and full moon, but the moon always appeared round and could not show the first and third quarters; the new design turns it by gears so that every phase of waxing, waning, and visibility matches the sky. The old device only struck bells and drums for clepsydra marks and double-hours; it could not show how day and night lengthen and shorten or how sunrise, sunset, watches, and night watches shift. The new design adds a Time-Keeper figure that drives a twelve-hour wheel and points to each moment, and a Candle Dragon on a bronze lotus that, at the proper hour, releases a pearl, shakes the lotus, and sets the ring turning on its own. Every feature of the design goes beyond what Yi Xing had accomplished. Among its parts, the component that fully represents the celestial sphere is the armillary sphere itself, the Xuanji; and the part that drives the water scoop is the Yuheng. Earlier scholars sometimes identified the entire Jiji-Yuheng with the armillary sphere, or called a globe with Ji but no Heng a celestial model, or took the sighting tube of the armillary instrument for the Heng — all of which is mistaken. Some did not even know what sort of instrument the Jiji and Yuheng were meant to be. Only Zheng Xuan identified the rotating component as Ji and the stabilizing component as Heng; compared with the present mechanism, his account comes nearest the truth.
143
西
As for the moon's phases, antiquity never fully explained them. Yang Xiong alone wrote, "Before the full moon its spirit is borne in the west; after the full moon its spirit ends in the east — does it follow the sun?" Jing Fang said, "The moon has form but no light of its own; only sunlight makes it bright." Thus it was understood that the moon has no inherent light and shines only by facing the sun. In our own dynasty Shen Kuo modeled the moon with a clay ball, whitened half its surface to represent sunlight, and viewed it head-on and from the side, thereby showing every shape from full disk to crescent. The present mechanism agrees with all three accounts as if their seals matched exactly. The responsible offices should be ordered to establish a workshop from the model, choose a site within the Bright Hall or Joint Terrace, erect a platform, and install the instrument there to observe the heavens. Three additional instruments should be built: one for the Imperial Storehouse, one for the Bell and Drum Court, and one kept ready for the emperor's travels. A full book should also be compiled so that the design may instruct generations to come.
144
An edict established the Bureau for Discussing and Manufacturing the Jiji and Yuheng, placed Fu in overall charge, and made the inner attendant Liang Shicheng his deputy.
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