Source Code
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These source-code files are part of a reconstructed copy of Luminary 173, the
second (unflown) release of the Apollo 14 Lunar Module (LM) Apollo Guidance
Computer (AGC) software.
The reconstruction began with reconstructed source code for Luminary 178. Changes
between revision 173 and 178 were backed out, as described by Luminary memo 167
(revision 1). 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 173 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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042269,000002: ## Copyright: Public domain.
042270,000003: ## Filename: LUNAR_AND_SOLAR_EPHEMERIDES_SUBROUTINES.agc
042271,000004: ## Purpose: A section of Luminary revision 173.
042272,000005: ## It is part of the reconstructed source code for the second
042273,000006: ## (unflown) release of the flight software for the Lunar
042274,000007: ## Module's (LM) Apollo Guidance Computer (AGC) for Apollo 14.
042275,000008: ## The code has been recreated from a reconstructed copy of
042276,000009: ## Luminary 178, as well as Luminary memo 167 (revision 1).
042277,000010: ## It has been adapted such that the resulting bugger words
042278,000011: ## exactly match those specified for Luminary 173 in NASA
042279,000012: ## drawing 2021152N, which gives relatively high confidence
042280,000013: ## that the reconstruction is correct.
042281,000014: ## Reference: pp. 975-978
042282,000015: ## Assembler: yaYUL
042283,000016: ## Contact: Ron Burkey <info@sandroid.org>.
042284,000017: ## Website: www.ibiblio.org/apollo/index.html
042285,000018: ## Mod history: 2019-09-18 MAS Created from Luminary 178.
042286,000019:
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Page 975
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042288,000021: # NAME - LSPOS - LOCATE SUN AND MOON DATE - 25 OCT 67
042289,000022: # MOD NO.1
042290,000023: # MOD BY NEVILLE ASSEMBLY SUNDANCE
042291,000024:
042292,000025: # FUNCTIONAL DESCRIPTION
042293,000026:
042294,000027: # COMPUTES UNIT POSITION VECTOR OF THE SUN AND MOON IN THE BASIC REFERENCE SYSTEM. THE SUN VECTOR S IS
042295,000028: # LOCATED VIA TWO ANGLES. THE FIRST ANGLE(OBLIQUITY) IS THE ANGLE BETWEEN THE EARTH EQUATOR AND THE ECLIPTIC. THE
042296,000029: # SECOND ANGLE IS THE LONGITUDE OF THE SUN MEASURED IN THE ECLIPTIC.
042297,000030: # THE POSITION VECTOR OF THE SUN IS
042298,000031: # -
042299,000032: # S=(COS(LOS), COS(OBL)*SIN(LOS), SIN(OBL)*SIN(LOS)), WHERE
042300,000033:
042301,000034: # LOS=LOS +LOS *T-(C *SIN(2PI*T)/365.24 +C *COS(2PI*T)/365.24)
042302,000035: # 0 R 0 1
042303,000036: # LOS (RAD) IS THE LONGITUDE OF THE SUN FOR MIDNIGHT JUNE 30TH OF THE PARTICULAR YEAR.
042304,000037: # 0
042305,000038: # LOS (RAD/DAY) IS THE MEAN RATE FOR THE PARTICULAR YEAR.
042306,000039: # R
042307,000040: # LOS AND LOS ARE STORED AS LOSC AND LOSR IN RATESP.
042308,000041: # 0 R
042309,000042: # COS(OBL) AND SIN(OBL) ARE STORED IN THE MATRIX KONMAT.
042310,000043: # T, TIME MEASURED IN DAYS(24 HOURS), IS STORED IN TIMEP.
042311,000044: # C AND C ARE FUDGE FACTORS TO MINIMIZE THE DEVIATION. THEY ARE STORED AS ONE CONSTANT(CMOD), SINCE
042312,000045: # 0 1 2 2 1/2
042313,000046: # C *SIN(X)+C *COS(X) CAN BE WRITTEN AS (C +C ) *SIN(X+PHI), WHERE PHI=ARCTAN(C /C ).
042314,000047: # 0 1 0 1 1 0
042315,000048:
042316,000049: # THE MOON IS LOCATED VIA FOUR ANGLES. THE FIRST IS THE OBLIQUITY. THE SECOND IS THE MEAN LONGITUDE OF THE MOON,
042317,000050: # MEASURED IN THE ECLIPTIC FROM THE MEAN EQUINOX TO THE MEAN ASCENDING NODE OF THE LUNAR ORBIT, AND THEN ALONG THE
042318,000051: # ORBIT. THE THIRD ANGLE IS THE ANGLE BETWEEN THE ECLIPTIC AND THE LUNAR ORBIT. THE FOURTH ANGLE IS THE LONGITUDE
042319,000052: # OF THE NODE OF THE MOON, MEASURED IN THE LUNAR ORBIT. LET THESE ANGLES BE OBL,LOM,IM, AND LON RESPECTIVELY.
042320,000053:
042321,000054: # THE SIMPLIFIED POSITION VECTOR OF THE MOON IS
042322,000055: # -
042323,000056: # 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))
042324,000057:
042325,000058: # WHERE
042326,000059: # 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
042327,000060: # 0 R 0 1 0 1
042328,000061: # LON=LON +LON
042329,000062: # 0 R
042330,000063: # A , A , B AND B ARE STORED AS AMOD AND BMOD (SEE DESCRIPTION OF CMOD, ABOVE). COS(OBL), SIN(OBL)*SIN(IM),
042331,000064: # 0 1 0 1
042332,000065: # SIN(OBL), AND COS(OBL)*SIN(IM) ARE STORED IN KONMAT AS K1, K2, K3 AND K4, RESPECTIVELY. LOM , LOM , LON , LON
042333,000066: # ARE STORED AS LOMO, LOMR, LONO, AND LONR IN RATESP. 0 R 0 R
042334,000067: # THE THREE PHIS ARE STORED AS AARG, BARG, AND CARG(SUN). ALL CONSTANTS ARE UPDATED BY YEAR.
042335,000068:
042336,000069: # CALLING SEQUENCE
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Page 976
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042338,000071: # CALL LSPOS. RETURN IS VIA CPRET.
042339,000072:
042340,000073: # ALARMS OR ABORTS
042341,000074:
042342,000075: # NONE
042343,000076:
042344,000077: # ERASABLE INITIALIZATION REQUIRED
042345,000078:
042346,000079: # TEPHEM - TIME FROM MIDNIGHT 1 JULY PRECEDING THE LAUNCH TO THE TIME OF THE LAUNCH (WHEN THE AGC CLOCK WENT
042347,000080: # TO ZERO). TEPHEM IS TP WITH UNITS OF CENTI-SECONDS.
042348,000081: # TIME2 AND TIME1 ARE IN MPAC AND MPAC +1 WHEN PROGRAM IS CALLED.
042349,000082:
042350,000083: # OUTPUT
042351,000084:
042352,000085: # UNIT POSITIONAL VECTOR OF SUN IN VSUN. (SCALED B-1)
042353,000086: # UNIT POSITIONAL VECTOR OF MOON IN VMOON. (SCALED B-1)
042354,000087:
042355,000088: # SUBROUTINES USED
042356,000089:
042357,000090: # NONE
042358,000091:
042359,000092: # DEBRIS
042360,000093:
042361,000094: # CURRENT CORE SET,WORK AREA AND FREEFLAG
042362,000095: 04,3001 BANK 04
042363,000096: 15,2000 SETLOC EPHEM
042364,000097: 15,2000 BANK
042365,000098:
042366,000099: 15,3660 E5,1714 EBANK= VSUN
042367,000100: 15,3660 COUNT* $$/EPHEM
042368,000101: 15,3660 15,3660 LUNPOS EQUALS LSPOS
042369,000102:
042370,000103: 15,3660 54201 LSPOS SETPD SR
042371,000104: 15,3661 00001 0
042372,000105: 15,3662 20617 14D # TP
042373,000106: 15,3663 56371 TAD DDV
042374,000107: 15,3664 01707 TEPHEM # TIME OF LAUNCH
042375,000108: 15,3665 12024 CSTODAY # 24 HOURS-8640000 CENTI-SECS/DAY B-33
042376,000109: 15,3666 00031 STORE TIMEP # T IN DAYS
042377,000110: 15,3667 77170 AXT,1 AXT,2
042378,000111: 15,3670 00000 0
042379,000112: 15,3671 00000 0
042380,000113: 15,3672 77614 CLEAR
042381,000114: 15,3673 00274 FREEFLAG # SWITCH BIT
042382,000115: 15,3674 77745 POSITA DLOAD
042383,000116: 15,3675 12004 KONMAT +2 # ZEROS
042384,000117: 15,3676 00027 STORE GTMP
042385,000118: 15,3677 40745 POSITB DLOAD DMP*
042386,000119: 15,3700 00031 TIMEP # T
042387,000120: 15,3701 12050 VAL67 +4,1 # 1/27 OR 1/32 OR 1/365
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Page 977
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042389,000122: 15,3702 42661 SL DAD*
042390,000123: 15,3703 20211 8D
042391,000124: 15,3704 12046 VAL67 +2,1 # AARG
042392,000125: 15,3705 40756 SIN DMP* # SIN(T/27+PHI) OR T/32 OR T/365
042393,000126: 15,3706 12044 VAL67,1 # (A0**2+A1**2)**1/2SIN(X+PHIA)
042394,000127: 15,3707 62015 DAD INCR,1 # PLUS
042395,000128: 15,3710 00027 GTMP # (B0**2+B1**2)**1/2SIN(X+PHIB)
042396,000129: 15,3711 77771 DEC -6 B-14
042397,000130: 15,3712 00027 STORE GTMP # OR (C0**2+C1**2)**1/2SIN(X+PHIC)
042398,000131: 15,3713 77614 BOFSET
042399,000132: 15,3714 00054 FREEFLAG
042400,000133: 15,3715 33677 POSITB
042401,000134: 15,3716 40745 POSITD DLOAD DMP*
042402,000135: 15,3717 00031 TIMEP # T
042403,000136: 15,3720 65747 RATESP,2 # LOMR,LOSR,LONR
042404,000137: 15,3721 42661 SL DAD*
042405,000138: 15,3722 20206 5D
042406,000139: 15,3723 65741 RATESP +6,2 # LOMO,LOSO,LONO
042407,000140: 15,3724 77625 DSU
042408,000141: 15,3725 00027 GTMP
042409,000142: 15,3726 10021 STORE STMP,2 # LOM,LOS,LON
042410,000143: 15,3727 63135 SLOAD INCR,2
042411,000144: 15,3730 00050 X2
042412,000145: 15,3731 77775 DEC -2 B-14
042413,000146: 15,3732 53015 DAD BZE
042414,000147: 15,3733 12026 RCB-13 # PLUS 2
042415,000148: 15,3734 33764 POSITE # 2ND
042416,000149: 15,3735 77644 BPL
042417,000150: 15,3736 33674 POSITA # 1ST
042418,000151: 15,3737 45345 POSITF DLOAD DSU # 3RD
042419,000152: 15,3740 00021 STMP # LOM
042420,000153: 15,3741 00025 STMP +4 # LON
042421,000154: 15,3742 65356 SIN PDDL # SIN(LOM-LON)
042422,000155: 15,3743 00021 STMP
042423,000156: 15,3744 65356 SIN PDDL # SIN LOM
042424,000157: 15,3745 00021 STMP
042425,000158: 15,3746 55546 COS VDEF # COS LOM
042426,000159: 15,3747 53521 MXV UNIT
042427,000160: 15,3750 12002 KONMAT # K1,K2,K3,K4,
042428,000161: 15,3751 02723 STORE VMOON
042429,000162: 15,3752 65345 DLOAD PDDL
042430,000163: 15,3753 12004 KONMAT +2 # ZERO
042431,000164: 15,3754 00023 STMP +2
042432,000165: 15,3755 65356 SIN PDDL # SIN LOS
042433,000166: 15,3756 00023 STMP +2
042434,000167: 15,3757 55546 COS VDEF # COS LOS
042435,000168: 15,3760 53521 MXV UNIT
042436,000169: 15,3761 12002 KONMAT
042437,000170: 15,3762 02715 STORE VSUN
042438,000171: 15,3763 77616 RVQ
042439,000172:
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Page 978
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042441,000174: 15,3764 77745 POSITE DLOAD
042442,000175: 15,3765 12004 KONMAT +2 # ZEROS
042443,000176: 15,3766 00027 STORE GTMP
042444,000177: 15,3767 77650 GOTO
042445,000178: 15,3770 33716 POSITD
042446,000179: 05,2000 SETLOC EPHEM1
042447,000180: 05,2000 BANK
042448,000181:
042449,000182: 05,3510 COUNT* $$/EPHEM
042450,000183:
042451,000184: 05,3510 STMP EQUALS 16D
042452,000185:
042453,000186: 05,3510 GTMP EQUALS 22D
042454,000187:
042455,000188: 05,3510 TIMEP EQUALS 24D
End of include-file LUNAR_AND_SOLAR_EPHEMERIDES_SUBROUTINES.agc. Parent file is MAIN.agc