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卷五十七 志第九: 曆六

Volume 57 Treatises 10: Calendar 6

Chapter 57 of 元史 · History of Yuan
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1
Gengwu Yuan Calendar, lower part — Step Convergence Procedure: convergence termination parts 142,319; seconds 9,306; micro-units 20. Convergence termination day: 27 days, remainder 1,109 parts, seconds 9,306, micro-units 20.
2
Convergence mid-cycle day: 13 days, remainder 3,169 parts, seconds 4,653, micro-units 10. Convergence new-moon day: 2 days, remainder 1,665 parts, seconds 693, micro-units 80. Convergence full-moon day: 14 days, remainder 4,002 parts, seconds 5,000.
3
Seconds mother: 10,000. Micro mother: 100. Convergence termination degree: 363°, 79 parts, 36 seconds. Convergence middle degree: 181°, 89 parts, 68 seconds.
4
Convergence image degree: 90°, 94 parts, 84 seconds. Half convergence image degree: 45°, 47 parts, 42 seconds. Solar eclipse totality anterior limit: 2,400. Fixed method: 248. Solar eclipse totality posterior limit: 3,100. Fixed method: 320.
5
Lunar eclipse limit: 5,100. Lunar eclipse totality limit: 1,700. Fixed method: 340. Parts-and-seconds mother: each 100.
6
To find new and full moon entry into convergence. (First set the li difference, halve it, take one-ninth of that value, and add or subtract from the civil new-year new-moon accumulated parts accordingly; only then proceed.)
7
滿 便 仿
Set the civil new-year new-moon accumulated parts, discard full convergence termination parts, divide the remainder by the day divisor for days and parts, and obtain the eleventh-month central new-moon general convergence day, remainder, and seconds. (This is the central new-moon hour-of-addition general convergence day and remainder.) Add the convergence new-moon increment to obtain the next new moon; Add the convergence full-moon increment to obtain the full moon; Add the convergence full-moon increment again to obtain the next new moon; Each yields the general convergence day, remainder, and seconds for every new and full moon. (Whenever remainder seconds are named, micro-units follow likewise; treat other remainders the same way.)
8
〈To find the fixed new moon and daily midnight entry into convergence〉
9
退退 滿
Set each general convergence day and remainder seconds, subtract the central new- or full-moon minor remainder, and obtain the fixed new or full moon midnight general convergence day and remainder seconds. If a fixed new or full moon advances or retreats, adjust the convergence day likewise; otherwise take the central value as fixed. Add two days in a long month and one in a short month; always add 4,120 to the remainder with seconds 693 and micro-units 80 for the next new moon's midnight convergence entry; Add one day cumulatively, cast out full convergence termination days and remainder seconds, and obtain each day's midnight general convergence day and remainder seconds.
10
〈To find fixed new and full moon hour-of-addition entry into convergence〉
11
Set the central new- and full-moon hour-of-addition general convergence day and remainder seconds, apply the entry-into-qi and entry-into-rotation tiao–chuo fixed numbers (tiao subtract, chuo add), and obtain the fixed new- and full-moon hour-of-addition general convergence day and remainder seconds. 〈To find fixed new- and full-moon hour-of-addition convergence accumulated degrees and yang/yin calendar〉
12
滿退
Set the fixed new- or full-moon hour-of-addition general convergence day, convert through the day divisor with the remainder, shift two places, divide by 39,121 for degrees, reduce the remainder to parts and seconds, and obtain the hour-of-addition moon's entry into convergence accumulated degree; Apply the fixed syzygy hour's entry-into-rotation slow-fast degree (slow subtract, fast add) to obtain the moon's fixed entry into convergence accumulated degree; At or below convergence middle counts as yang-calendar accumulated degree; above, subtract it to obtain yin-calendar accumulated degree. (For each midnight, follow this procedure.)
13
〈To find the moon's ecliptic latitude (departure from the yellow path)〉
14
退滿 滿
Inspect the entered yin- or yang-calendar accumulated degree and parts; at or below the convergence image counts as the young image; above, cover and subtract convergence middle; the remainder is the old image. Set the entered young or old image degree above and the convergence image degree below, subtract and multiply, double and shift one place for parts, convert hundreds to degrees, and subtract from the entered young or old image degree and parts; then with the remainder subtract and multiply against convergence middle, multiply by eight, divide by 110 for parts, convert hundreds to degrees, and obtain the moon's departure from the yellow path in degrees and parts.
15
〈To find new- and full-moon hour-of-addition general and fixed convergence days〉
16
Set the new- or full-moon general convergence day, apply the entry-into-qi tiao–chuo fixed number (tiao subtract, chuo add), and obtain the general convergence day. Set the entry-into-rotation tiao–chuo fixed number, shift one place, divide by 127, apply tiao subtract and chuo add to the general convergence day, and obtain the fixed convergence day and remainder seconds.
17
〈To find entry-into-convergence yang/yin calendar before and after parts〉
18
Inspect the fixed entry-into-convergence day; at or below convergence middle counts as yang calendar; above, subtract it — yin calendar. If within about one day, convert the day through the day divisor into parts with the remainder included — that is the after-convergence part; If within about thirteen days, cover and subtract the convergence mid-cycle day to obtain the before-convergence part.
19
〈To find the fixed remainder for solar and lunar eclipse greatest〉
20
退
Set the new- and full-moon entry-into-qi and entry-into-rotation tiao–chuo fixed numbers, combine same names and cancel different names, multiply by 1,337, divide by the fixed syzygy hour's entry-into-rotation count-outside rotation fixed parts, apply tiao subtract and chuo add to the central new- and full-moon minor remainder, and obtain the general remainder. Solar eclipse: if the general remainder is at or below the half method, it is before middle; at or above the half method, subtract the half method for after middle. Set the before- and after-middle parts, subtract and multiply against the half method, double, and reduce by 10,000 to obtain the time difference. Before middle: subtract the time difference from the general remainder to obtain the fixed remainder; cover and subtract the half method — the remainder is the before-noon part; After middle: add the time difference to the general remainder to obtain the fixed remainder; Subtract the half method to obtain the after-noon part. Lunar eclipse: if the general remainder falls after sunset and before midnight, at or below three-quarters of the day divisor subtract the half method for the before-you part; Above three-quarters, cover and subtract the day divisor for the after-you part. If after midnight and before sunrise, at or below one-quarter of the day divisor counts as before-mao; Above one-quarter, cover and subtract the half method for the after-mao part. Self-multiply each of the before- and after-mao and before- and after-you parts, multiply by four, shift one place back, reduce by 10,000 for parts, add to the general remainder, and obtain the fixed remainder. Set each fixed remainder and apply the aggregation-and-release hour-of-addition method to obtain the double-hour and ke of eclipse greatest.
21
〈To find the solar motion accumulated degree at eclipse greatest〉
22
Set the fixed syzygy eclipse-greatest major and minor remainders, subtract the central syzygy major and minor remainders, and with the difference adjust the central syzygy entry-into-qi day remainder, (When the central syzygy day count is less, add more and subtract less.) That is the entry into qi at eclipse greatest; Add that to the qi mid-accumulation to obtain the mid-accumulation at eclipse greatest. Set the entry-into-qi remainder at eclipse greatest and multiply by that qi day's gain-and-loss rate (the excess-and-deficit gain-and-loss.) Multiply, divide by the day divisor, adjust that day's excess-and-deficit accumulation, then excess adds and deficit subtracts from the eclipse-greatest mid-accumulation to obtain the eclipse-greatest daily solar motion accumulated degree and parts. First reduce the eclipse-greatest mid-accumulation canonical parts, then add and subtract; for similar remainders, follow the same procedure.
23
〈To find qi difference〉
24
滿
Set the solar eclipse-greatest daily solar motion accumulated degree and parts, cast out the central limit, and if the remainder is at or below the image limit it is the initial limit; if above, cover and subtract the central limit for the final limit; self-multiply in each case, shift two places, divide by 478, subtract from 1,744, and obtain the qi-difference constant; Multiply by the before- or after-noon part, divide by half the day-length part, subtract from the constant, and obtain the fixed number. (If subtraction fails, cover and subtract instead; where addition is indicated, subtract; where subtraction is indicated, add.) After the spring equinox, yang calendar subtracts and yin calendar adds; After the autumn equinox, yang calendar adds and yin calendar subtracts. (Before the spring equinox and after the autumn equinox, treat two days and 2,100 parts each as fixed qi and apply these additions and subtractions within that interval.)
25
〈To find ke difference〉
26
滿
Set the solar-eclipse-greatest solar daily accumulated degree and parts, discard full middle limits, multiply the remainder by its distance from the middle limit, advance two places, divide by 478, and obtain the ke-difference constant; Multiply by the before- and after-noon parts and divide by one quarter of the day divisor to obtain the fixed number. (If above the constant, double the constant, subtract the obtained number for the fixed number, and apply the indicated additions or subtractions.) After winter solstice, before noon add in the yang case and subtract in the yin case; after noon subtract in the yang case and add in the yin case; After summer solstice, before noon subtract in the yang case and add in the yin case; after noon add in the yang case and subtract in the yin case.
27
〈To find the solar eclipse fixed distance from crossing before and after〉
28
Set the qi- and quarter-mark-difference fixed numbers, combine those of the same name and cancel those of different name, and obtain the eclipse difference; Apply the additions and subtractions to the crossing before-and-after parts to obtain the fixed crossing before-and-after parts. Inspect the before-and-after fixed parts: in the yang calendar there is no eclipse; in the yin calendar there is an eclipse. If before crossing in the yin calendar subtraction is insufficient, reverse the subtraction, (reverse-subtract the eclipse difference.) that becomes after-crossing yang calendar; if after crossing in the yin calendar subtraction is insufficient, reverse the subtraction to obtain before-crossing yang calendar; then there is no eclipse. if before crossing in the yang calendar subtraction is insufficient, reverse the subtraction to obtain after-crossing yin calendar; if after crossing in the yang calendar subtraction is insufficient, reverse the subtraction to obtain before-crossing yin calendar; then that day there is a solar eclipse.
29
〈To find the solar eclipse parts〉
30
退
Inspect the fixed crossing before-and-after parts: at 2,400 or below take before-totality parts; divide by 248 for great parts; If 2,400 or above, cover and subtract 5,500, (if subtraction is insufficient, there is no eclipse.) these are after-totality parts; divide by 320 for great parts and convert any remainder into seconds. (At one part or below the crossing is too shallow, the sun's light too strong, and the eclipse may not be visible.)
31
〈To find the lunar eclipse parts〉
32
退
Inspect the crossing before-and-after parts, (without using the qi and quarter-mark differences.) at 1,700 or below the eclipse is total; if above, cover and subtract 5,100, (if subtraction is insufficient, there is no eclipse.) Divide the remainder by 340 for great parts; Convert any remainder into seconds to obtain the lunar eclipse parts and seconds. If the distance-from-crossing parts are at or below the totality limit, cover and subtract the totality limit and likewise divide by 340 for the great parts within totality.
33
〈To find the solar eclipse fixed usage parts〉
34
Set the solar eclipse great parts, subtract and multiply with 20 parts, multiply by 2,450, divide by the fixed new moon's outside-rotation fixed parts, and obtain the fixed usage parts; Subtract from the fixed remainder to obtain the first-diminishment parts; Add to the fixed remainder to obtain the restoration-of-roundness parts; Apply the expansion-contraction hour-addition method to each to obtain the solar eclipse's three-limit chen and ke.
35
〈To find the lunar eclipse fixed usage parts〉
36
Set the lunar eclipse great parts, subtract and multiply with 35 parts, multiply by 2,100, divide by the fixed full moon's outside-rotation fixed parts, and obtain the fixed usage parts; Add and subtract the fixed remainder to obtain the first-diminishment and restoration-of-roundness parts. Apply the expansion-contraction hour-addition method to each to obtain the lunar eclipse's three-limit chen and ke.
37
For a total lunar eclipse, take the within-totality great parts, subtract and multiply with 15 parts, multiply by 4,200, divide by the fixed full moon's outside-rotation fixed parts, and obtain the within-totality parts; Subtract these from the fixed usage parts to obtain the outside-totality parts. Set the lunar eclipse fixed remainder, subtract the fixed usage parts, and obtain the first-diminishment parts; Then add the outside-totality parts to obtain the eclipse-totality parts; Again add the within-totality parts to obtain the greatest-eclipse parts; (This is the fixed remainder parts.) Again add the within-totality parts to obtain the light-generation parts; Again add the outside-totality parts to obtain the restoration-of-roundness parts. Apply the expansion-contraction hour-addition method to each to obtain the lunar eclipse's five-limit chen, ke, and parts. (For a total lunar eclipse, add ten parts to the within-totality great parts and by that method obtain the fixed usage parts.)
38
〈To find the lunar eclipse's entry into watch and point〉
39
滿 滿
Set the day's dawn parts at greatest eclipse, double them, and five-reduce to obtain the watch method; Again five-reduce to obtain the point method. Then set the lunar eclipse's beginning-and-end parts: above dusk parts subtract dusk parts; below dawn parts add dawn parts; if insufficient for the watch method, that is the first watch; Any remainder short of the point divisor counts as one point. Apply the method in order to each limit to obtain the watch and point counts.
40
〈Procedure to find the solar eclipse's direction of first contact〉
41
西 西 西
Before totality, first contact lies southwest, maximum due south, and recovery southeast. After totality, first contact lies 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 (at noon).)
42
〈Procedure to find the lunar eclipse's direction of first contact〉
43
西 西 西
With the moon in the yang calendar, first contact is northeast, maximum due north, and recovery northwest. With the moon in the yin calendar, 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 likewise assumes an observer on the local meridian (at noon).)
44
Procedure to find the fraction of a solar or lunar eclipse visible when caught at sunrise or sunset
45
滿 退 退
For each case, subtract the sun's rise-or-set parts from the eclipse-maximum minor remainder to obtain the horizon-partial difference; multiply by the eclipsed fraction and divide by the fixed usage parts; (For a total lunar eclipse, subtract the within-totality parts from the horizon-partial difference, multiply the remainder by the eclipsed fraction and divide by the outside-totality parts; 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.)
46
宿
〈Procedure to find the lodge at solar or lunar eclipse maximum〉
47
宿宿
Set the daily-motion accumulated degrees at eclipse maximum for sun or moon, (at full moon add the full-moon degree.) Add to the winter solstice ecliptic solar degree at hour-of-addition, name the lodges, and remove by the ecliptic lodge sequence to obtain each eclipse-maximum lodge degree, parts, and seconds for sun or moon.
48
Procedures for the Five Planets — Jupiter cycle rate: 2,086,142; seconds 9. Calendar rate: 22,650,557.
49
Circuit degree divisor: 62,014. Circuit day: 398 days, 88 parts. Circuit degree: 365 degrees, 24 parts, 90 seconds. Circuit mid: 182 degrees, 62 parts, 45 seconds.
50
Circuit stride: 15 degrees, 21 parts, 87 seconds. Heliacal setting visibility: 13 degrees.
51
(The tables below are omitted.) Mars cycle rate: 4,079,042; seconds 14 and a half. Calendar rate: 3,592,757; seconds 44 slight.
52
Circuit degree divisor: 9,836½. Circuit day: 779 days, 93 parts, 16 seconds. Circuit degree: 365 degrees, 24 parts, 75 seconds. Circuit mid: 182°62′37.5″.
53
Circuit stride: 15°21′86″. Heliacal setting visibility: 19 degrees.
54
(The tables below are omitted.) Saturn cycle rate: 1,977,411; seconds 69. Calendar rate: 56,223,248½.
55
Circuit degree divisor: 153,928. Circuit day: 378 days, 9 parts, 2 seconds. Circuit degree: 365°25′68″. Circuit mid: 182°62′84″.
56
Circuit stride: 15°21′90″. Heliacal setting visibility: 17 degrees.
57
(The tables below are omitted.) Venus cycle rate: 3,053,804; seconds 63 great. Calendar rate: 1,910,240; seconds 76½.
58
Circuit degree divisor: 5,230. Circuit day: 583 days, 90 parts, 14 seconds. Conjunction day: 291 days, 95 parts, 7 seconds. Circuit degree: 365°24′68″.
59
Circuit mid: 182°62′34″. Circuit stride: 15°21′86″. Heliacal setting visibility: 10½ degrees.
60
(The tables below are omitted.) Mercury cycle rate: 606,031; seconds 77½. Calendar rate: 1,910,242; seconds 13½.
61
Circuit degree divisor: 5,230. Circuit day: 115 days, 87 parts, 60 seconds. Conjunction day: 57 days, 93 parts, 80 seconds. Circuit degree: 365°24′70″.
62
Circuit mid: 182°62′35″. Circuit stride: 15°21′85″. Morning hidden, evening visible: 14 degrees. Evening hidden, morning visible: 19 degrees.
63
(The tables below are omitted.) 〈To find each planet's mean conjunction after heavenly-origin winter solstice and the central accumulation and central star for every segment〉
64
滿退 退
Set the comprehensive accumulated parts, (First apply the inner difference.) For each star, cast out full cycle rates; the remainder is the anterior conjunction parts; Subtract the cycle rate again; the remainder is the posterior conjunction parts; Divide by the day divisor, reduce the remainder to parts and seconds, and obtain that star's mean-conjunction central accumulation and central star after heavenly-origin winter solstice. (Name the result as days—this is the central accumulation; (Name the result as degrees—this is the central star.) Add segment days cumulatively to the central accumulation to obtain each segment's central accumulation; Add mean degrees cumulatively to the central star, casting back when full, to obtain each segment's central star.
65
〈To find each planet's mean conjunction and every segment's entry into the circuit cycle〉
66
滿退
Set the comprehensive accumulated parts, add each star's posterior conjunction parts, cast out full calendar rates, divide the remainder by that star's circuit degree divisor for degrees, reduce the remainder to parts and seconds, and obtain the mean-conjunction entry-into-circuit degree and parts and seconds; Add each segment's limit degree cumulatively to obtain every segment's entry-into-circuit degree and parts and seconds.
67
〈To find each planet's mean conjunction and every segment's excess-and-deficit fixed difference〉
68
Set each star and segment's entry-into-circuit degree and parts and seconds; at or below the circuit mid counts as excess; if above, subtract the circuit mid; the remainder is in deficit. Divide by that star's calendar stride to obtain the stride count; the remainder is the entry-into-stride degree and parts. Name from outside the stride count, multiply the tabulated loss-and-gain rate, divide the remainder by the circuit stride for parts, apply it to the underlying excess-and-deficit accumulation, and obtain that star and segment's excess-and-deficit fixed difference.
69
〈To find each planet's mean conjunction and every segment's fixed accumulation〉
70
滿滿
Set each star and segment's central accumulation and add or subtract the segment's excess-and-deficit fixed difference according to excess or deficit to obtain the segment's fixed-accumulation days and parts; Add to the heavenly-origin winter solstice greater remainder and approximate parts, cast out full era rules, name from renxu outside the count, and obtain the day and double-hour. 〈To find each planet's mean conjunction and every segment's month and day〉
71
Set each segment's fixed accumulation, add heavenly-origin intercalary days and approximate parts, and divide by the new-moon policy and approximate parts for month count; the remainder is the days and parts elapsed within the month. Name the month count from heavenly-origin month eleven outside the count to obtain the segment's days and parts since mean new moon; take the day-and-double-hour interval as the fixed new-moon month and day.
72
〈To find each planet's mean conjunction and every segment's hour-of-addition fixed star〉
73
宿宿
Set each central star and apply the excess-and-deficit fixed difference (add in excess, subtract in deficit), (Double for Venus and triple for Mercury, then add or subtract.) The result is each planet's fixed star for every segment; Add to the heavenly-origin winter solstice ecliptic solar degree at hour of addition, name the lodge accordingly, and obtain that star and segment's lodge degree and parts and seconds at hour of addition.
74
〈To find each planet's fixed star at dawn before midnight on the first day of each segment〉
75
退宿
Multiply each segment's initial motion rate by the hour-of-addition parts under the segment's fixed-accumulation day, reduce by 100, subtract in forward motion and add in retrograde to that day's hour-of-addition fixed star, and obtain the lodge degree and parts and seconds of the segment-first-day dawn-before-midnight fixed star. 〈To find each segment's day rate and degree rate〉
76
宿宿
Take each segment's day-and-double-hour interval to the next segment as the day rate. Subtract this segment's midnight lodge sequence from the next segment's; the remainder is the degree rate. 〈To find each segment's parallel motion parts〉
77
Set each segment's degree rate and parts and seconds, divide by that segment's day rate, and obtain its parallel motion degree and parts and seconds. 〈To find each segment's total difference and daily difference〉
78
仿 退
Subtract this segment's prior and subsequent parallel motion parts; the remainder is its general difference; (To find Jupiter's second-fast general difference, subtract forward-swift from forward-slow parallel motion parts; the remainder is the second-fast general difference; all other cases follow this pattern.) Double the general difference and shift back one place for the increase-decrease difference; Add or subtract it from parallel motion parts to obtain initial and final day motion parts; (If the prior exceeds the subsequent, add for the initial day and subtract for the final day; (If the prior is less and the subsequent more, subtract for the initial day and add for the final day.) Double the increase-decrease difference for the total difference; Divide by the day rate minus one to obtain the daily difference.
79
退
〈To find the increase-decrease differences for prior and subsequent concealment, slow, and retrograde segments〉
80
退退 退退 退 退
For prior concealment, set the next segment's initial-day motion parts, add half its daily difference, and obtain final-day motion parts; For subsequent concealment, set the prior segment's final-day motion parts, add half its daily difference, and obtain initial-day motion parts; Subtract from the concealment segment's parallel motion parts; the remainder is the increase-decrease difference. For prior slow motion, set the prior segment's final-day motion parts, subtract double its daily difference, and obtain initial-day motion parts; For subsequent slow motion, set the next segment's initial-day motion parts, subtract double its daily difference, and obtain final-day motion parts; Subtract from the slow segment's parallel motion parts; the remainder is the increase-decrease difference. (Slow segments before and after that lie near station.) For Jupiter, Mars, and Saturn in retrograde, multiply parallel motion parts by six, shift back one place, and obtain the increase-decrease difference. For Venus at prior and subsequent concealment and retrograde, multiply parallel motion parts by three, halve and shift back one place, and obtain the increase-decrease difference. For prior retrograde, set the next segment's initial-day motion parts, subtract its daily difference, and obtain final-day motion parts. For subsequent retrograde, set the prior segment's final-day motion parts, subtract its daily difference, and obtain initial-day motion parts; Subtract from this segment's parallel motion parts; the remainder is the increase-decrease difference. For Mercury, take the parallel motion parts as the increase-decrease difference, then add or subtract it from parallel motion parts to obtain initial and final day motion parts. (If the prior exceeds the subsequent, add for the initial day and subtract for the final day; (if the prior is less and the subsequent more, subtract for the initial day and add for the final day.) Again double the increase-decrease difference for the total difference and divide by the day rate minus one to obtain the daily difference.
81
宿
〈To find each day's star lodge sequence at dawn before midnight〉
82
退滿宿宿 使
Set each segment's initial-day motion parts and apply the daily difference cumulatively, (Subtract when the subsequent value is less and add when it is more.) The result is each day's motion in degrees, parts, and seconds; Then add in forward motion and subtract in retrograde, cast out full lodge sequences, and obtain each day's star lodge sequence at dawn before midnight. (Compare the prior segment's final-day and next segment's initial-day motion parts; a gap of no more than one or two daily differences is ideal; If the daily difference is many times too large or the sequence is inverted and incoherent, reconcile it with the surrounding increase-decrease differences, adjust slightly until coherent, and then apply it. If prior and subsequent parallel motion parts are both too large or both too small, distribute the correction evenly; If the total difference's seconds do not reach one part, distribute evenly as well; (If the values are incoherent but even distribution restores coherence, distribute evenly.)
83
〈To find each planet's mean conjunction and appearance-and-concealment entry into qi〉
84
滿
Set the fixed accumulation, divide by the qi stride and approximate parts for the qi count, take the remainder as days, parts, and seconds entered into qi; name from heavenly-origin winter solstice outside the count, and obtain the mean conjunction and appearance-and-concealment entry-into-qi days, parts, and seconds. 〈To find each planet's mean conjunction and appearance-and-concealment motion difference〉
85
退退
Subtract the sun's motion parts from each segment's initial-day star motion parts; the remainder is the motion difference. If Venus is retrograde or Mercury at retrograde conjunction, add the two for the motion difference. When Mercury is evening concealed and morning visible, take the sun's motion parts directly as the motion difference. 〈To find each planet's fixed conjunction, appearance, and concealment general accumulation〉
86
滿退 退
For Jupiter, Mars, and Saturn, the mean-conjunction morning-swift evening-concealed fixed accumulation is the fixed conjunction, appearance, and concealment general accumulation. For Venus and Mercury, set that segment's excess-and-deficit fixed difference, (Double it for Mercury.) divide each by the motion difference for days, and reduce any remainder to parts and seconds; at mean conjunction with evening visibility and morning concealment, subtract in excess and add in deficit; at retrograde conjunction with evening concealment and morning visibility, add in excess and subtract in deficit; Apply the indicated additions and subtractions to the fixed accumulation to obtain the fixed conjunction, appearance, and concealment general accumulation.
87
〈To find each planet's fixed conjunction fixed accumulation and fixed star〉
88
退退 退 退 滿 滿宿宿 退
For Jupiter, Mars, and Saturn, divide each day's solar excess-and-deficit difference by the mean-conjunction motion difference to obtain the conjunction-distance difference day; Subtract from the solar excess-and-deficit difference to obtain the conjunction-distance difference degree; When the sun is in excess, subtract the difference day and difference degree; When in the deficit cycle, add them; Add or subtract on that star's fixed-conjunction general accumulation to obtain the fixed conjunction fixed accumulation and fixed star. For Venus and Mercury in direct or retrograde conjunction, divide that day's solar excess-and-deficit difference by the corresponding mean-conjunction motion difference to obtain the conjunction-distance difference day; Add the solar excess-and-deficit difference in direct motion and subtract it in retrograde motion to obtain the conjunction-distance difference degree; In direct motion when in the excess cycle, add the difference day and difference degree; When in the deficit cycle, subtract them; In retrograde motion when in the excess cycle, subtract the difference day and add the difference degree; When in the deficit cycle, add the difference day and subtract the difference degree; Apply the indicated additions and subtractions to that star's fixed star, fixed conjunction, and second fixed-conjunction general accumulation to obtain the fixed conjunction, second fixed conjunction, fixed accumulation, and fixed star; Add the fixed accumulation to the winter solstice greater remainder and approximate parts, cast out full era rules, name the count, and obtain the fixed conjunction day and double-hour; Add the fixed star to the winter solstice ecliptic solar degree at hour of addition, remove full lodge sequences, and obtain the lodge of the fixed conjunction. (Whether the motion is direct or retrograde, the excess or deficit used is the sun's excess and deficit.)
89
〈To find the fixed appearance, concealment, and fixed day for Jupiter, Mars, and Saturn〉
90
滿 滿退
Set each star's fixed appearance-and-concealment general accumulation; at dawn add and at dusk subtract the image-limit day and parts and seconds; (Half the middle limit serves as the image limit.) If at or below the middle limit, square it; If above, overlay-subtract from the year circuit day and parts and seconds and square the remainder likewise; Divide by 75, multiply by that star's heliacal appearance-and-concealment degree, and divide by 15 to obtain the difference. Divide the difference by that segment's motion difference for days; cast back the remainder into parts and seconds; Add at appearance and subtract at concealment on the general accumulation to obtain the fixed accumulation; Add and name as before to obtain the day and double-hour.
91
〈To find the fixed appearance, concealment, and fixed day for Venus and Mercury〉
92
滿滿退
For each star, divide that day's solar excess-and-deficit difference by the appearance-concealment daily motion difference to obtain days. For morning concealment and evening appearance, add when the sun is in the excess cycle; when in the deficit cycle, subtract; For evening concealment and morning appearance, subtract when the sun is in excess and add when in the deficit cycle; Add or subtract on that star's general accumulation to obtain the regular accumulation. Inspect the regular accumulation: at or below the middle limit is after winter solstice; above it, cast out the middle limit and take the remainder as after summer solstice. After each solstice, square values at or below the image limit; above it, overlay-subtract from the middle limit and square the remainder likewise; divide each by the appropriate divisor to obtain parts, (After winter solstice at dawn and after summer solstice at dusk, use 18 as the divisor; (after winter solstice at dusk and after summer solstice at dawn, use 75 as the divisor.) Multiply by the heliacal appearance-and-concealment degree and divide by 15 to obtain the difference. When the difference fills the motion difference, take one for days; cast back the remainder into parts and seconds; Add or subtract on the regular accumulation to obtain the fixed accumulation; (After winter solstice, for morning appearance and evening concealment, add; for evening appearance and morning concealment, subtract. After summer solstice, for morning appearance and evening concealment, subtract; (for evening appearance and morning concealment, add.) Add and name as before to obtain the fixed appearance-and-concealment day and double-hour.
93
For Mercury in evening swift motion from the start of Great Heat through day 9, part 35 of Start of Winter, it is invisible; When in morning station from the start of Great Cold through day 9, part 35 of Start of Summer, it is invisible. That it is not seen at dawn in spring or at dusk in autumn was also recorded in older calendars.
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