Source Code
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This is a reconstructed version of Luminary 130, the initial AGC program released
in November 1969 for the Apollo 13 LM. Three more releases
followed before the flown revision was finally manufactured in February 1970.
This reconstruction was created from a previous transcription of the original listing of
Luminary 131, combined with Luminary memo #129 which describes the small difference
between the Luminary 130 and 131. The reconstructed source code was verified by
matching memory-bank checksums to those listed for Luminary 130 in drawing 2021152G.
In this source code, program comments from the original (Luminary 131) code are
prefixed with '#', while those added later by the Virtual AGC project are prefixed
with '##'.
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042099,000002: ## Copyright: Public domain.
042100,000003: ## Filename: LUNAR_AND_SOLAR_EPHEMERIDES_SUBROUTINES.agc
042101,000004: ## Purpose: A section of the reconstructed source code for Luminary 130.
042102,000005: ## This was the original program released for the Apollo 13 LM,
042103,000006: ## although several more revisions would follow. It has been
042104,000007: ## reconstructed from a listing of Luminary 131, from which it
042105,000008: ## differs on only two lines in P70-P71. The difference is
042106,000009: ## described in detail in Luminary memo #129, which was used
042107,000010: ## to perform the reconstruction. This file is intended to be a
042108,000011: ## faithful reconstruction, except that the code format has been
042109,000012: ## changed to conform to the requirements of the yaYUL assembler
042110,000013: ## rather than the original YUL assembler.
042111,000014: ## Reference: pp. 978-981
042112,000015: ## Contact: Ron Burkey <info@sandroid.org>.
042113,000016: ## Website: www.ibiblio.org/apollo/index.html
042114,000017: ## Mod history: 05/29/03 RSB. Began transcribing.
042115,000018: ## 05/14/05 RSB Corrected website reference above.
042116,000019: ## 2017-01-06 RSB Page numbers now agree with those on the
042117,000020: ## original hardcopy, as opposed to the PDF page
042118,000021: ## numbers in 1701.pdf.
042119,000022: ## 2017-02-26 RSB Proofed comment text using octopus/ProoferComments.
042120,000023: ## 2017-03-13 RSB Comment-text fixes noted in proofing Luminary 116.
042121,000024: ## 2017-08-26 MAS Fixed comment-text errors found while transcribing Zerlina 56.
042122,000025: ## 2018-09-04 MAS Copied from Luminary 131 for Luminary 130.
042123,000026:
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Page 978
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042125,000028: # NAME - LSPOS - LOCATE SUN AND MOON DATE - 25 OCT 67
042126,000029: # MOD NO.1
042127,000030: # MOD BY NEVILLE ASSEMBLY SUNDANCE
042128,000031:
042129,000032: # FUNCTIONAL DESCRIPTION
042130,000033:
042131,000034: # COMPUTES UNIT POSITION VECTOR OF THE SUN AND MOON IN THE BASIC REFERENCE SYSTEM. THE SUN VECTOR S IS
042132,000035: # LOCATED VIA TWO ANGLES. THE FIRST ANGLE (OBLIQUITY) IS THE ANGLE BETWEEN THE EARTH EQUATOR AND THE ECLIPTIC. THE
042133,000036: # SECOND ANGLE IS THE LONGITUDE OF THE SUN MEASURED IN THE ECLIPTIC.
042134,000037: # THE POSITION VECTOR OF THE SUN IS
042135,000038: # -
042136,000039: # S = (COS(LOS), COS(OBL)*SIN(LOS), SIN(OBL)*SIN(LOS)), WHERE
042137,000040:
042138,000041: # LOS = LOS +LOS *T-(C *SIN(2PI*T)/365.24 +C *COS(2PI*T)/365.24)
042139,000042: # 0 R 0 1
042140,000043: # LOS (RAD) IS THE LONGITUDE OF THE SUN FOR MIDNIGHT JUNE 30TH OF THE PARTICULAR YEAR.
042141,000044: # 0
042142,000045: # LOS (RAD/DAY) IS THE MEAN RATE FOR THE PARTICULAR YEAR.
042143,000046: # R
042144,000047:
042145,000048: # LOS AND LOS ARE STORED AS LOSC AND LOSR IN RATESP.
042146,000049: # 0 R
042147,000050: # COS(OBL) AND SIN(OBL) ARE STORED IN THE MATRIX KONMAT.
042148,000051:
042149,000052: # T, TIME MEASURED IN DAYS (24 HOURS), IS STORED IN TIMEP.
042150,000053:
042151,000054: # C AND C ARE FUDGE FACTORS TO MINIMIZE THE DEVIATION. THEY ARE STORED AS ONE CONSTANT (CMOD), SINCE
042152,000055: # 0 1 2 2 1/2
042153,000056: # C *SIN(X)+C *COS(X) CAN BE WRITTEN AS (C +C ) *SIN(X+PHI), WHERE PHI=ARCTAN(C /C ).
042154,000057: # 0 1 0 1 1 0
042155,000058:
042156,000059: # THE MOON IS LOCATED VIA FOUR ANGLES. THE FIRST IS THE OBLIQUITY. THE SECOND IS THE MEAN LONGITUDE OF THE MOON,
042157,000060: # MEASURED IN THE ECLIPTIC FROM THE MEAN EQUINOX TO THE MEAN ASCENDING NODE OF THE LUNAR ORBIT, AND THEN ALONG THE
042158,000061: # ORBIT. THE THIRD ANGLE IS THE ANGLE BETWEEN THE ECLIPTIC AND THE LUNAR ORBIT. THE FOURTH ANGLE IS THE LONGITUDE
042159,000062: # OF THE NODE OF THE MOON, MEASURED IN THE LUNAR ORBIT. LET THESE ANGLES BE OBL,LOM,IM, AND LON RESPECTIVELY.
042160,000063:
042161,000064: # THE SIMPLIFIED POSITION VECTOR OF THE MOON IS
042162,000065: # -
042163,000066: # M=(COS(LOM), COS(OBL)*SIN(LOM)-SIN(OBL)*SIN(IM)*SIN(LOM-LON), SIN(OBL)*SIN(LOM)+COS(OBL)*SIN(IM)*SIN(LOM-LON))
042164,000067:
042165,000068: # WHERE
042166,000069: # LOM=LOM +LOM *T-(A *SIN 2PI*T/27.5545+A *COS(2PI*T/27.5545)+B *SIN 2PI*T/32+B *COS(2PI*T/32)), AND
042167,000070: # 0 R 0 1 0 1
042168,000071: # LON=LON +LON
042169,000072: # 0 R
042170,000073: # A , A , B AND B ARE STORED AS AMOD AND BMOD (SEE DESCRIPTION OF CMOD, ABOVE). COS(OBL), SIN(OBL)*SIN(IM),
042171,000074: # 0 1 0 1
042172,000075: # SIN(OBL), AND COS(OBL)*SIN(IM) ARE STORED IN KONMAT AS K1, K2, K3 AND K4, RESPECTIVELY. LOM , LOM , LON , LON
042173,000076: # ARE STORED AS LOMO, LOMR, LONO, AND LONR IN RATESP. 0 R 0 R
042174,000077:
042175,000078: # THE THREE PHIS ARE STORED AS AARG, BARG, AND CARG(SUN). ALL CONSTANTS ARE UPDATED BY YEAR.
042176,000079:
042177,000080: # CALLING SEQUENCE
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Page 979
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042179,000082: # CALL LSPOS. RETURN IS VIA CPRET.
042180,000083:
042181,000084: # ALARMS OR ABORTS
042182,000085: # NONE
042183,000086:
042184,000087: # ERASABLE INITIALIZATION REQUIRED
042185,000088: # TEPHEM - TIME FROM MIDNIGHT 1 JULY PRECEDING THE LAUNCH TO THE TIME OF THE LAUNCH (WHEN THE AGC CLOCK WENT
042186,000089: # TO ZERO). TEPHEM IS TP WITH UNITS OF CENTI-SECONDS.
042187,000090:
042188,000091: # TIME2 AND TIME1 ARE IN MPAC AND MPAC +1 WHEN PROGRAM IS CALLED.
042189,000092:
042190,000093: # OUTPUT
042191,000094: # UNIT POSITIONAL VECTOR OF SUN IN VSUN. (SCALED B-1)
042192,000095: # UNIT POSITIONAL VECTOR OF MOON IN VMOON. (SCALED B-1)
042193,000096:
042194,000097: # SUBROUTINES USED
042195,000098: # NONE
042196,000099:
042197,000100: # DEBRIS
042198,000101: # CURRENT CORE SET, WORK AREA AND FREEFLAG
042199,000102:
042200,000103: 04,2773 BANK 04
042201,000104: 15,2000 SETLOC EPHEM
042202,000105: 15,2000 BANK
042203,000106:
042204,000107: 15,3647 E5,1714 EBANK= VSUN
042205,000108: 15,3647 COUNT* $$/EPHEM
042206,000109: 15,3647 15,3647 LUNPOS EQUALS LSPOS
042207,000110:
042208,000111: 15,3647 54201 LSPOS SETPD SR
042209,000112: 15,3650 00001 0
042210,000113: 15,3651 20617 14D # TP
042211,000114: 15,3652 56371 TAD DDV
042212,000115: 15,3653 01707 TEPHEM # TIME OF LAUNCH
042213,000116: 15,3654 12024 CSTODAY # 24 HOURS-8640000 CENTI-SECS/DAY B-33
042214,000117: 15,3655 00031 STORE TIMEP # T IN DAYS
042215,000118: 15,3656 77170 AXT,1 AXT,2
042216,000119: 15,3657 00000 0
042217,000120: 15,3660 00000 0
042218,000121: 15,3661 77614 CLEAR
042219,000122: 15,3662 00274 FREEFLAG # SWITCH BIT
042220,000123: 15,3663 77745 POSITA DLOAD
042221,000124: 15,3664 12004 KONMAT +2 # ZEROS
042222,000125: 15,3665 00027 STORE GTMP
042223,000126: 15,3666 40745 POSITB DLOAD DMP*
042224,000127: 15,3667 00031 TIMEP # T
042225,000128: 15,3670 12050 VAL67 +4,1 # 1/27 OR 1/32 OR 1/365
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Page 980
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042227,000130: 15,3671 42661 SL DAD*
042228,000131: 15,3672 20211 8D
042229,000132: 15,3673 12046 VAL67 +2,1 # AARG
042230,000133: 15,3674 40756 SIN DMP* # SIN(T/27+PHI) OR T/32 OR T/365
042231,000134: 15,3675 12044 VAL67,1 # (A0**2+A1**2)**1/2 SIN(X+PHIA)
042232,000135: 15,3676 62015 DAD INCR,1 # PLUS
042233,000136: 15,3677 00027 GTMP # (B0**2+B1**2)**1/2 SIN(X+PHIB)
042234,000137: 15,3700 77771 DEC -6 B-14
042235,000138: 15,3701 00027 STORE GTMP # OR (C0**2+C1**2)**1/2 SIN(X+PHIC)
042236,000139: 15,3702 77614 BOFSET
042237,000140: 15,3703 00054 FREEFLAG
042238,000141: 15,3704 33666 POSITB
042239,000142: 15,3705 40745 POSITD DLOAD DMP*
042240,000143: 15,3706 00031 TIMEP # T
042241,000144: 15,3707 65747 RATESP,2 # LOMR,LOSR,LONR
042242,000145: 15,3710 42661 SL DAD*
042243,000146: 15,3711 20206 5D
042244,000147: 15,3712 65741 RATESP +6,2 # LOMO,LOSO,LONO
042245,000148: 15,3713 77625 DSU
042246,000149: 15,3714 00027 GTMP
042247,000150: 15,3715 10021 STORE STMP,2 # LOM,LOS,LON
042248,000151: 15,3716 63135 SLOAD INCR,2
042249,000152: 15,3717 00050 X2
042250,000153: 15,3720 77775 DEC -2 B-14
042251,000154: 15,3721 53015 DAD BZE
042252,000155: 15,3722 12026 RCB-13 # PLUS 2
042253,000156: 15,3723 33753 POSITE # 2ND
042254,000157: 15,3724 77644 BPL
042255,000158: 15,3725 33663 POSITA # 1ST
042256,000159: 15,3726 45345 POSITF DLOAD DSU # 3RD
042257,000160: 15,3727 00021 STMP # LOM
042258,000161: 15,3730 00025 STMP +4 # LON
042259,000162: 15,3731 65356 SIN PDDL # SIN(LOM-LON)
042260,000163: 15,3732 00021 STMP
042261,000164: 15,3733 65356 SIN PDDL # SIN LOM
042262,000165: 15,3734 00021 STMP
042263,000166: 15,3735 55546 COS VDEF # COS LOM
042264,000167: 15,3736 53521 MXV UNIT
042265,000168: 15,3737 12002 KONMAT # K1,K2,K3,K4,
042266,000169: 15,3740 02723 STORE VMOON
042267,000170: 15,3741 65345 DLOAD PDDL
042268,000171: 15,3742 12004 KONMAT +2 # ZERO
042269,000172: 15,3743 00023 STMP +2
042270,000173: 15,3744 65356 SIN PDDL # SIN LOS
042271,000174: 15,3745 00023 STMP +2
042272,000175: 15,3746 55546 COS VDEF # COS LOS
042273,000176: 15,3747 53521 MXV UNIT
042274,000177: 15,3750 12002 KONMAT
042275,000178: 15,3751 02715 STORE VSUN
042276,000179: 15,3752 77616 RVQ
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Page 981
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042278,000181: 15,3753 77745 POSITE DLOAD
042279,000182: 15,3754 12004 KONMAT +2 # ZEROS
042280,000183: 15,3755 00027 STORE GTMP
042281,000184: 15,3756 77650 GOTO
042282,000185: 15,3757 33705 POSITD
042283,000186: 05,2000 SETLOC EPHEM1
042284,000187: 05,2000 BANK
042285,000188:
042286,000189: 05,3505 COUNT* $$/EPHEM
042287,000190: 05,3505 STMP EQUALS 16D
042288,000191: 05,3505 GTMP EQUALS 22D
042289,000192: 05,3505 TIMEP EQUALS 24D
042290,000193:
End of include-file LUNAR_AND_SOLAR_EPHEMERIDES_SUBROUTINES.agc. Parent file is MAIN.agc