Source Code
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These source-code files are part of a reconstructed copy of Luminary 97, the
second release of the Apollo 11 Lunar Module (LM) Apollo Guidance Computer
(AGC) software. It was created to fix two incorrect ephemeris constants in
Luminary 96, as described by anomaly report LNY-59.
The reconstruction began with source code of Luminary 99 revision 1 previously
transcribed from a digitized copy of that program. The code was then updated
by undoing changes described in original Luminary memos 83 and 85, using asterisks
indicating changed lines in the listing as a guide. The reconstruction was
verified by matching memory-bank checksums to those listed in drawing 2021152D.
Note that page numbers in the reconstructed code match those on the Luminary 099
revision 001 printout, although the added code would likely have changed page
numbers for a real Luminary 97 listing.
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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042179,000002: ## Copyright: Public domain.
042180,000003: ## Filename: LUNAR_AND_SOLAR_EPHEMERIDES_SUBROUTINES.agc
042181,000004: ## Purpose: A section of Luminary revision 97.
042182,000005: ## It is part of the reconstructed source code for the
042183,000006: ## second release of the flight software for the Lunar
042184,000007: ## Module's (LM) Apollo Guidance Computer (AGC) for Apollo 11.
042185,000008: ## It was created to fix two incorrect ephemeris constants in
042186,000009: ## Luminary 96, as described by anomaly report LNY-59.
042187,000010: ## The code has been recreated from a copy of Luminary 99
042188,000011: ## revision 001, using asterisks indicating changed lines in
042189,000012: ## the listing and Luminary Memos #83 and #85, which list
042190,000013: ## changes between Luminary 97 and 98, and 98 and 99. The
042191,000014: ## code has been adapted such that the resulting bugger words
042192,000015: ## exactly match those specified for Luminary 97 in NASA drawing
042193,000016: ## 2021152D, which gives relatively high confidence that the
042194,000017: ## reconstruction is correct.
042195,000018: ## Reference: pp. 984-987
042196,000019: ## Assembler: yaYUL
042197,000020: ## Contact: Ron Burkey <info@sandroid.org>.
042198,000021: ## Website: www.ibiblio.org/apollo/index.html
042199,000022: ## Mod history: 2019-07-28 MAS Created from Luminary 99.
042200,000023:
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Page 984
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042202,000025: # NAME - LSPOS - LOCATE SUN AND MOON DATE - 25 OCT 67
042203,000026: # MOD NO. 1
042204,000027: # MOD BY NEVILLE ASSEMBLY SUNDANCE
042205,000028:
042206,000029: # FUNCTIONAL DESCRIPTION
042207,000030:
042208,000031: # COMPUTES UNIT POSITION VECTOR OF THE SUN AND MOON IN THE BASIC REFERENCE SYSTEM. THE SUN VECTOR S IS
042209,000032: # LOCATED VIA TWO ANGLES. THE FIRST ANGLE(OBLIQUITY) IS THE ANGLE BETWEEN THE EARTH EQUATOR AND THE ECLIPTIC. THE
042210,000033: # SECOND ANGLE IS THE LONGITUDE OF THE SUN MEASURED IN THE ECLIPTIC.
042211,000034: # THE POSITION VECTOR OF THE SUN IS
042212,000035: # -
042213,000036: # S = (COS(LOS), COS(OBL)*SIN(LOS), SIN(OBL)*SIN(LOS)), WHERE
042214,000037:
042215,000038: # LOS = LOS +LOS *T-(C *SIN(2PI*T)/365.24 +C *COS(2PI*T)/365.24)
042216,000039: # 0 R 0 1
042217,000040: # LOS (RAD) IS THE LONGITUDE OF THE SUN FOR MIDNIGHT JUNE 30TH OF THE PARTICULAR YEAR.
042218,000041: # 0
042219,000042: # LOS (RAD/DAY) IS THE MEAN RATE FOR THE PARTICULAR YEAR.
042220,000043: # R
042221,000044:
042222,000045: # LOS AND LOS ARE STORED AS LOSC AND LOSR IN RATESP.
042223,000046: # 0 R
042224,000047: # COS(OBL) AND SIN(OBL) ARE STORED IN THE MATRIX KONMAT.
042225,000048:
042226,000049: # T, TIME MEASURED IN DAYS (24 HOURS), IS STORED IN TIMEP.
042227,000050:
042228,000051: # C AND C ARE FUDGE FACTORS TO MINIMIZE THE DEVIATION. THEY ARE STORED AS ONE CONSTANT (CMOD), SINCE
042229,000052: # 0 1 2 2 1/2
042230,000053: # C *SIN(X)+C *COS(X) CAN BE WRITTEN AS (C +C ) *SIN(X+PHI), WHERE PHI=ARCTAN(C /C ).
042231,000054: # 0 1 0 1 1 0
042232,000055:
042233,000056: # THE MOON IS LOCATED VIA FOUR ANGLES. THE FIRST IS THE OBLIQUITY. THE SECOND IS THE MEAN LONGITUDE OF THE MOON,
042234,000057: # MEASURED IN THE ECLIPTIC FROM THE MEAN EQUINOX TO THE MEAN ASCENDING NODE OF THE LUNAR ORBIT, AND THEN ALONG THE
042235,000058: # ORBIT. THE THIRD ANGLE IS THE ANGLE BETWEEN THE ECLIPTIC AND THE LUNAR ORBIT. THE FOURTH ANGLE IS THE LONGITUDE
042236,000059: # OF THE NODE OF THE MOON, MEASURED IN THE LUNAR ORBIT. LET THESE ANGLES BE OBL,LOM,IM, AND LON RESPECTIVELY.
042237,000060:
042238,000061: # THE SIMPLIFIED POSITION VECTOR OF THE MOON IS
042239,000062: # -
042240,000063: # 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))
042241,000064:
042242,000065: # WHERE
042243,000066: # 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
042244,000067: # 0 R 0 1 0 1
042245,000068: # LON=LON +LON
042246,000069: # 0 R
042247,000070: # A , A , B AND B ARE STORED AS AMOD AND BMOD (SEE DESCRIPTION OF CMOD, ABOVE). COS(OBL), SIN(OBL)*SIN(IM),
042248,000071: # 0 1 0 1
042249,000072: # SIN(OBL), AND COS(OBL)*SIN(IM) ARE STORED IN KONMAT AS K1, K2, K3 AND K4, RESPECTIVELY. LOM , LOM , LON , LON
042250,000073: # ARE STORED AS LOMO, LOMR, LONO, AND LONR IN RATESP. 0 R 0 R
042251,000074: # THE THREE PHIS ARE STORED AS AARG, BARG, AND CARG(SUN). ALL CONSTANTS ARE UPDATED BY YEAR.
042252,000075:
042253,000076: # CALLING SEQUENCE
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Page 985
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042255,000078: # CALL LSPOS. RETURN IS VIA CPRET.
042256,000079:
042257,000080: # ALARMS OR ABORTS
042258,000081: # NONE
042259,000082:
042260,000083: # ERASABLE INITIALIZATION REQUIRED
042261,000084: # TEPHEM - TIME FROM MIDNIGHT 1 JULY PRECEDING THE LAUNCH TO THE TIME OF THE LAUNCH (WHEN THE AGC CLOCK WENT
042262,000085: # TO ZERO). TEPHEM IS TP WITH UNITS OF CENTI-SECONDS.
042263,000086:
042264,000087: # TIME2 AND TIME1 ARE IN MPAC AND MPAC +1 WHEN PROGRAM IS CALLED.
042265,000088:
042266,000089: # OUTPUT
042267,000090: # UNIT POSITIONAL VECTOR OF SUN IN VSUN. (SCALED B-1)
042268,000091: # UNIT POSITIONAL VECTOR OF MOON IN VMOON. (SCALED B-1)
042269,000092:
042270,000093: # SUBROUTINES USED
042271,000094: # NONE
042272,000095:
042273,000096: # DEBRIS
042274,000097: # CURRENT CORE SET, WORK AREA AND FREEFLAG
042275,000098:
042276,000099: 04,3027 BANK 04
042277,000100: 15,2000 SETLOC EPHEM
042278,000101: 15,2000 BANK
042279,000102:
042280,000103: 15,3664 E5,1714 EBANK= VSUN
042281,000104: 15,3664 COUNT* $$/EPHEM
042282,000105: 15,3664 15,3664 LUNPOS EQUALS LSPOS
042283,000106:
042284,000107: 15,3664 54201 LSPOS SETPD SR
042285,000108: 15,3665 00001 0
042286,000109: 15,3666 20617 14D # TP
042287,000110: 15,3667 56371 TAD DDV
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The hand-written notation "in centisec B 42" appears to the right.
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042289,000112: 15,3670 01707 TEPHEM # TIME OF LAUNCH
042290,000113: 15,3671 12024 CSTODAY # 24 HOURS-8640000 CENTI-SECS/DAY B-33
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The hand-written notation "@ B 9 = 512 days" appears to the right.
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042292,000115: 15,3672 00031 STORE TIMEP # T IN DAYS
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The hand-written notation "∴ granularity ≈ 0.164 sec" appears to the right.
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042294,000117: 15,3673 77170 AXT,1 AXT,2
042295,000118: 15,3674 00000 0
042296,000119: 15,3675 00000 0
042297,000120: 15,3676 77614 CLEAR
042298,000121: 15,3677 00274 FREEFLAG # SWITCH BIT
042299,000122: 15,3700 77745 POSITA DLOAD
042300,000123: 15,3701 12004 KONMAT +2 # ZEROS
042301,000124: 15,3702 00027 STORE GTMP
042302,000125: 15,3703 40745 POSITB DLOAD DMP*
042303,000126: 15,3704 00031 TIMEP # T
042304,000127: 15,3705 12050 VAL67 +4,1 # 1/27 OR 1/32 OR 1/365
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Page 986
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042306,000129: 15,3706 42661 SL DAD*
042307,000130: 15,3707 20211 8D
042308,000131: 15,3710 12046 VAL67 +2,1 # AARG
042309,000132: 15,3711 40756 SIN DMP* # SIN(T/27+PHI) OR T/32 OR T/365
042310,000133: 15,3712 12044 VAL67,1 # (A0**2+A1**2)**1/2 SIN(X+PHIA)
042311,000134: 15,3713 62015 DAD INCR,1 # PLUS
042312,000135: 15,3714 00027 GTMP # (B0**2+B1**2)**1/2 SIN(X+PHIB)
042313,000136: 15,3715 77771 DEC -6 B-14
042314,000137: 15,3716 00027 STORE GTMP # OR (C0**2+C1**2)**1/2 SIN(X+PHIC)
042315,000138: 15,3717 77614 BOFSET
042316,000139: 15,3720 00054 FREEFLAG
042317,000140: 15,3721 33703 POSITB
042318,000141: 15,3722 40745 POSITD DLOAD DMP*
042319,000142: 15,3723 00031 TIMEP # T
042320,000143: 15,3724 65747 RATESP,2 # LOMR,LOSR,LONR
042321,000144: 15,3725 42661 SL DAD*
042322,000145: 15,3726 20206 5D
042323,000146: 15,3727 65741 RATESP +6,2 # LOMO,LOSO,LONO
042324,000147: 15,3730 77625 DSU
042325,000148: 15,3731 00027 GTMP
042326,000149: 15,3732 10021 STORE STMP,2 # LOM,LOS,LON
042327,000150: 15,3733 63135 SLOAD INCR,2
042328,000151: 15,3734 00050 X2
042329,000152: 15,3735 77775 DEC -2 B-14
042330,000153: 15,3736 53015 DAD BZE
042331,000154: 15,3737 12026 RCB-13 # PLUS 2
042332,000155: 15,3740 33770 POSITE # 2ND
042333,000156: 15,3741 77644 BPL
042334,000157: 15,3742 33700 POSITA # 1ST
042335,000158: 15,3743 45345 POSITF DLOAD DSU # 3RD
042336,000159: 15,3744 00021 STMP # LOM
042337,000160: 15,3745 00025 STMP +4 # LON
042338,000161: 15,3746 65356 SIN PDDL # SIN(LOM-LON)
042339,000162: 15,3747 00021 STMP
042340,000163: 15,3750 65356 SIN PDDL # SIN LOM
042341,000164: 15,3751 00021 STMP
042342,000165: 15,3752 55546 COS VDEF # COS LOM
042343,000166: 15,3753 53521 MXV UNIT
042344,000167: 15,3754 12002 KONMAT # K1,K2,K3,K4,
042345,000168: 15,3755 02723 STORE VMOON
042346,000169: 15,3756 65345 DLOAD PDDL
042347,000170: 15,3757 12004 KONMAT +2 # ZERO
042348,000171: 15,3760 00023 STMP +2
042349,000172: 15,3761 65356 SIN PDDL # SIN LOS
042350,000173: 15,3762 00023 STMP +2
042351,000174: 15,3763 55546 COS VDEF # COS LOS
042352,000175: 15,3764 53521 MXV UNIT
042353,000176: 15,3765 12002 KONMAT
042354,000177: 15,3766 02715 STORE VSUN
042355,000178: 15,3767 77616 RVQ
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Page 987
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042357,000180: 15,3770 77745 POSITE DLOAD
042358,000181: 15,3771 12004 KONMAT +2 # ZEROS
042359,000182: 15,3772 00027 STORE GTMP
042360,000183: 15,3773 77650 GOTO
042361,000184: 15,3774 33722 POSITD
042362,000185: 15,3775 77616 LUNVEL RVQ # TO FOOL INTEGRATION
042363,000186: 05,2000 SETLOC EPHEM1
042364,000187: 05,2000 BANK
042365,000188:
042366,000189: 05,3506 COUNT* $$/EPHEM
042367,000190: 05,3506 STMP EQUALS 16D
042368,000191: 05,3506 GTMP EQUALS 22D
042369,000192: 05,3506 TIMEP EQUALS 24D
042370,000193:
End of include-file LUNAR_AND_SOLAR_EPHEMERIDES_SUBROUTINES.agc. Parent file is MAIN.agc