Source Code
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These source-code files are part of a reconstructed copy of Luminary 178, the
final release of the Apollo 14 Lunar Module (LM) Apollo Guidance Computer
(AGC) software.
The reconstruction began with source code of Zerlina 56, Luminary 210, and
Luminary 131, previously transcribed from digitized copies of those programs.
The code was created by combining the three, using Zerlina 56 as a base, since
it was based off of Luminary 183. The differences between the three were
carefully merged using the Luminary memos as a guide, with all changes made
after Luminary 178 being backed out. The reconstruction was verified by matching
memory-bank checksums to those listed in drawing 2021152N. Note that page numbers
in the reconstructed code match those for the baseline log section mentioned in
each file's changelog; the page numbers for a real Luminary 178 listing would
be different.
Comments from the original source code are prefixed with a single '#' symbol,
whereas comments added later are prefixed by "##" or "###". Report any errors
noted by creating an
issue report at the Virtual AGC
project's GitHub repository.
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042360,000002: ## Copyright: Public domain.
042361,000003: ## Filename: LUNAR_AND_SOLAR_EPHEMERIDES_SUBROUTINES.agc
042362,000004: ## Purpose: A section of Luminary revision 178.
042363,000005: ## It is part of the reconstructed source code for the final
042364,000006: ## release of the flight software for the Lunar Module's
042365,000007: ## (LM) Apollo Guidance Computer (AGC) for Apollo 14. The
042366,000008: ## code has been recreated from copies of Zerlina 56, Luminary
042367,000009: ## 210, and Luminary 131, as well as many Luminary memos.
042368,000010: ## It has been adapted such that the resulting bugger words
042369,000011: ## exactly match those specified for Luminary 178 in NASA
042370,000012: ## drawing 2021152N, which gives relatively high confidence
042371,000013: ## that the reconstruction is correct.
042372,000014: ## Reference: pp. 975-978
042373,000015: ## Assembler: yaYUL
042374,000016: ## Contact: Ron Burkey <info@sandroid.org>.
042375,000017: ## Website: www.ibiblio.org/apollo/index.html
042376,000018: ## Mod history: 2019-08-14 MAS Created from Zerlina 56.
042377,000019:
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Page 975
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042379,000021: # NAME - LSPOS - LOCATE SUN AND MOON DATE - 25 OCT 67
042380,000022: # MOD NO.1
042381,000023: # MOD BY NEVILLE ASSEMBLY SUNDANCE
042382,000024:
042383,000025: # FUNCTIONAL DESCRIPTION
042384,000026:
042385,000027: # COMPUTES UNIT POSITION VECTOR OF THE SUN AND MOON IN THE BASIC REFERENCE SYSTEM. THE SUN VECTOR S IS
042386,000028: # LOCATED VIA TWO ANGLES. THE FIRST ANGLE(OBLIQUITY) IS THE ANGLE BETWEEN THE EARTH EQUATOR AND THE ECLIPTIC. THE
042387,000029: # SECOND ANGLE IS THE LONGITUDE OF THE SUN MEASURED IN THE ECLIPTIC.
042388,000030: # THE POSITION VECTOR OF THE SUN IS
042389,000031: # -
042390,000032: # S=(COS(LOS), COS(OBL)*SIN(LOS), SIN(OBL)*SIN(LOS)), WHERE
042391,000033:
042392,000034: # LOS=LOS +LOS *T-(C *SIN(2PI*T)/365.24 +C *COS(2PI*T)/365.24)
042393,000035: # 0 R 0 1
042394,000036: # LOS (RAD) IS THE LONGITUDE OF THE SUN FOR MIDNIGHT JUNE 30TH OF THE PARTICULAR YEAR.
042395,000037: # 0
042396,000038: # LOS (RAD/DAY) IS THE MEAN RATE FOR THE PARTICULAR YEAR.
042397,000039: # R
042398,000040: # LOS AND LOS ARE STORED AS LOSC AND LOSR IN RATESP.
042399,000041: # 0 R
042400,000042: # COS(OBL) AND SIN(OBL) ARE STORED IN THE MATRIX KONMAT.
042401,000043: # T, TIME MEASURED IN DAYS(24 HOURS), IS STORED IN TIMEP.
042402,000044: # C AND C ARE FUDGE FACTORS TO MINIMIZE THE DEVIATION. THEY ARE STORED AS ONE CONSTANT(CMOD), SINCE
042403,000045: # 0 1 2 2 1/2
042404,000046: # C *SIN(X)+C *COS(X) CAN BE WRITTEN AS (C +C ) *SIN(X+PHI), WHERE PHI=ARCTAN(C /C ).
042405,000047: # 0 1 0 1 1 0
042406,000048:
042407,000049: # THE MOON IS LOCATED VIA FOUR ANGLES. THE FIRST IS THE OBLIQUITY. THE SECOND IS THE MEAN LONGITUDE OF THE MOON,
042408,000050: # MEASURED IN THE ECLIPTIC FROM THE MEAN EQUINOX TO THE MEAN ASCENDING NODE OF THE LUNAR ORBIT, AND THEN ALONG THE
042409,000051: # ORBIT. THE THIRD ANGLE IS THE ANGLE BETWEEN THE ECLIPTIC AND THE LUNAR ORBIT. THE FOURTH ANGLE IS THE LONGITUDE
042410,000052: # OF THE NODE OF THE MOON, MEASURED IN THE LUNAR ORBIT. LET THESE ANGLES BE OBL,LOM,IM, AND LON RESPECTIVELY.
042411,000053:
042412,000054: # THE SIMPLIFIED POSITION VECTOR OF THE MOON IS
042413,000055: # -
042414,000056: # 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))
042415,000057:
042416,000058: # WHERE
042417,000059: # 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
042418,000060: # 0 R 0 1 0 1
042419,000061: # LON=LON +LON
042420,000062: # 0 R
042421,000063: # A , A , B AND B ARE STORED AS AMOD AND BMOD (SEE DESCRIPTION OF CMOD, ABOVE). COS(OBL), SIN(OBL)*SIN(IM),
042422,000064: # 0 1 0 1
042423,000065: # SIN(OBL), AND COS(OBL)*SIN(IM) ARE STORED IN KONMAT AS K1, K2, K3 AND K4, RESPECTIVELY. LOM , LOM , LON , LON
042424,000066: # ARE STORED AS LOMO, LOMR, LONO, AND LONR IN RATESP. 0 R 0 R
042425,000067: # THE THREE PHIS ARE STORED AS AARG, BARG, AND CARG(SUN). ALL CONSTANTS ARE UPDATED BY YEAR.
042426,000068:
042427,000069: # CALLING SEQUENCE
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Page 976
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042429,000071: # CALL LSPOS. RETURN IS VIA CPRET.
042430,000072:
042431,000073: # ALARMS OR ABORTS
042432,000074:
042433,000075: # NONE
042434,000076:
042435,000077: # ERASABLE INITIALIZATION REQUIRED
042436,000078:
042437,000079: # TEPHEM - TIME FROM MIDNIGHT 1 JULY PRECEDING THE LAUNCH TO THE TIME OF THE LAUNCH (WHEN THE AGC CLOCK WENT
042438,000080: # TO ZERO). TEPHEM IS TP WITH UNITS OF CENTI-SECONDS.
042439,000081: # TIME2 AND TIME1 ARE IN MPAC AND MPAC +1 WHEN PROGRAM IS CALLED.
042440,000082:
042441,000083: # OUTPUT
042442,000084:
042443,000085: # UNIT POSITIONAL VECTOR OF SUN IN VSUN. (SCALED B-1)
042444,000086: # UNIT POSITIONAL VECTOR OF MOON IN VMOON. (SCALED B-1)
042445,000087:
042446,000088: # SUBROUTINES USED
042447,000089:
042448,000090: # NONE
042449,000091:
042450,000092: # DEBRIS
042451,000093:
042452,000094: # CURRENT CORE SET,WORK AREA AND FREEFLAG
042453,000095: 04,3001 BANK 04
042454,000096: 15,2000 SETLOC EPHEM
042455,000097: 15,2000 BANK
042456,000098:
042457,000099: 15,3660 E5,1714 EBANK= VSUN
042458,000100: 15,3660 COUNT* $$/EPHEM
042459,000101: 15,3660 15,3660 LUNPOS EQUALS LSPOS
042460,000102:
042461,000103: 15,3660 54201 LSPOS SETPD SR
042462,000104: 15,3661 00001 0
042463,000105: 15,3662 20617 14D # TP
042464,000106: 15,3663 56371 TAD DDV
042465,000107: 15,3664 01707 TEPHEM # TIME OF LAUNCH
042466,000108: 15,3665 12024 CSTODAY # 24 HOURS-8640000 CENTI-SECS/DAY B-33
042467,000109: 15,3666 00031 STORE TIMEP # T IN DAYS
042468,000110: 15,3667 77170 AXT,1 AXT,2
042469,000111: 15,3670 00000 0
042470,000112: 15,3671 00000 0
042471,000113: 15,3672 77614 CLEAR
042472,000114: 15,3673 00274 FREEFLAG # SWITCH BIT
042473,000115: 15,3674 77745 POSITA DLOAD
042474,000116: 15,3675 12004 KONMAT +2 # ZEROS
042475,000117: 15,3676 00027 STORE GTMP
042476,000118: 15,3677 40745 POSITB DLOAD DMP*
042477,000119: 15,3700 00031 TIMEP # T
042478,000120: 15,3701 12050 VAL67 +4,1 # 1/27 OR 1/32 OR 1/365
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Page 977
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042480,000122: 15,3702 42661 SL DAD*
042481,000123: 15,3703 20211 8D
042482,000124: 15,3704 12046 VAL67 +2,1 # AARG
042483,000125: 15,3705 40756 SIN DMP* # SIN(T/27+PHI) OR T/32 OR T/365
042484,000126: 15,3706 12044 VAL67,1 # (A0**2+A1**2)**1/2SIN(X+PHIA)
042485,000127: 15,3707 62015 DAD INCR,1 # PLUS
042486,000128: 15,3710 00027 GTMP # (B0**2+B1**2)**1/2SIN(X+PHIB)
042487,000129: 15,3711 77771 DEC -6 B-14
042488,000130: 15,3712 00027 STORE GTMP # OR (C0**2+C1**2)**1/2SIN(X+PHIC)
042489,000131: 15,3713 77614 BOFSET
042490,000132: 15,3714 00054 FREEFLAG
042491,000133: 15,3715 33677 POSITB
042492,000134: 15,3716 40745 POSITD DLOAD DMP*
042493,000135: 15,3717 00031 TIMEP # T
042494,000136: 15,3720 65747 RATESP,2 # LOMR,LOSR,LONR
042495,000137: 15,3721 42661 SL DAD*
042496,000138: 15,3722 20206 5D
042497,000139: 15,3723 65741 RATESP +6,2 # LOMO,LOSO,LONO
042498,000140: 15,3724 77625 DSU
042499,000141: 15,3725 00027 GTMP
042500,000142: 15,3726 10021 STORE STMP,2 # LOM,LOS,LON
042501,000143: 15,3727 63135 SLOAD INCR,2
042502,000144: 15,3730 00050 X2
042503,000145: 15,3731 77775 DEC -2 B-14
042504,000146: 15,3732 53015 DAD BZE
042505,000147: 15,3733 12026 RCB-13 # PLUS 2
042506,000148: 15,3734 33764 POSITE # 2ND
042507,000149: 15,3735 77644 BPL
042508,000150: 15,3736 33674 POSITA # 1ST
042509,000151: 15,3737 45345 POSITF DLOAD DSU # 3RD
042510,000152: 15,3740 00021 STMP # LOM
042511,000153: 15,3741 00025 STMP +4 # LON
042512,000154: 15,3742 65356 SIN PDDL # SIN(LOM-LON)
042513,000155: 15,3743 00021 STMP
042514,000156: 15,3744 65356 SIN PDDL # SIN LOM
042515,000157: 15,3745 00021 STMP
042516,000158: 15,3746 55546 COS VDEF # COS LOM
042517,000159: 15,3747 53521 MXV UNIT
042518,000160: 15,3750 12002 KONMAT # K1,K2,K3,K4,
042519,000161: 15,3751 02723 STORE VMOON
042520,000162: 15,3752 65345 DLOAD PDDL
042521,000163: 15,3753 12004 KONMAT +2 # ZERO
042522,000164: 15,3754 00023 STMP +2
042523,000165: 15,3755 65356 SIN PDDL # SIN LOS
042524,000166: 15,3756 00023 STMP +2
042525,000167: 15,3757 55546 COS VDEF # COS LOS
042526,000168: 15,3760 53521 MXV UNIT
042527,000169: 15,3761 12002 KONMAT
042528,000170: 15,3762 02715 STORE VSUN
042529,000171: 15,3763 77616 RVQ
042530,000172:
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Page 978
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042532,000174: 15,3764 77745 POSITE DLOAD
042533,000175: 15,3765 12004 KONMAT +2 # ZEROS
042534,000176: 15,3766 00027 STORE GTMP
042535,000177: 15,3767 77650 GOTO
042536,000178: 15,3770 33716 POSITD
042537,000179: 05,2000 SETLOC EPHEM1
042538,000180: 05,2000 BANK
042539,000181:
042540,000182: 05,3510 COUNT* $$/EPHEM
042541,000183:
042542,000184: 05,3510 STMP EQUALS 16D
042543,000185:
042544,000186: 05,3510 GTMP EQUALS 22D
042545,000187:
042546,000188: 05,3510 TIMEP EQUALS 24D
End of include-file LUNAR_AND_SOLAR_EPHEMERIDES_SUBROUTINES.agc. Parent file is MAIN.agc