Notations on the program listing read, in part:
GAP: ASSEMBLE REVISION 116 OF AGC PROGRAM LUMINARY BY NASA 2021112-071 19:09 AUG. 11,1969Note that the date is the date of the printout, not the date of the program revision.
Source Code
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These source-code files derive from a printout of Luminary 116 (the Apollo 12
Lunar Module guidance computer program), from the personal library of
original AGC developer Don Eyles, digitally photographed at archive.org,
financially sponsored by Ron Burkey, and transcribed to source code by a
team of volunteers. This colorized, syntax-highlighted form was created
by assembling that transcribed source code. Note that the full page images
are available on the
Virtual AGC project page at archive.org, while reduced-size images
are presented at the VirtualAGC project website. Report or fix any
transcription errors at
the Virtual AGC project code repository. Notations on the program listing read, in part: GAP: ASSEMBLE REVISION 116 OF AGC PROGRAM LUMINARY BY NASA 2021112-071 19:09 AUG. 11,1969Note that the date is the date of the printout, not the date of the program revision. |
042112,000002: ## Copyright: Public domain.
042113,000003: ## Filename: LUNAR_AND_SOLAR_EPHEMERIDES_SUBROUTINES.agc
042114,000004: ## Purpose: A section of Luminary revision 116.
042115,000005: ## It is part of the source code for the Lunar Module's (LM)
042116,000006: ## Apollo Guidance Computer (AGC) for Apollo 12.
042117,000007: ## This file is intended to be a faithful transcription, except
042118,000008: ## that the code format has been changed to conform to the
042119,000009: ## requirements of the yaYUL assembler rather than the
042120,000010: ## original YUL assembler.
042121,000011: ## Reference: pp. 976-979
042122,000012: ## Assembler: yaYUL
042123,000013: ## Contact: Ron Burkey <info@sandroid.org>.
042124,000014: ## Website: www.ibiblio.org/apollo/index.html
042125,000015: ## Mod history: 2017-01-22 MAS Created from Luminary 99.
042126,000016: ## 2017-01-31 RRB Updated for Luminary 116.
042127,000017: ## 2017-03-13 RSB Proofed comment text via 3-way diff vs
042128,000018: ## Luminary 99 and 131.
042129,000019: ## 2017-08-26 MAS Fixed comment-text errors found while transcribing Zerlina 56.
042130,000020: ## 2021-05-30 ABS Fixed a page number to match scans.
042131,000021:
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Page 976 |
042133,000023: # NAME - LSPOS - LOCATE SUN AND MOON DATE - 25 OCT 67
042134,000024: # MOD NO. 1
042135,000025: # MOD BY NEVILLE ASSEMBLY SUNDANCE
042136,000026:
042137,000027: # FUNCTIONAL DESCRIPTION
042138,000028:
042139,000029: # COMPUTES UNIT POSITION VECTOR OF THE SUN AND MOON IN THE BASIC REFERENCE SYSTEM. THE SUN VECTOR S IS
042140,000030: # LOCATED VIA TWO ANGLES. THE FIRST ANGLE(OBLIQUITY) IS THE ANGLE BETWEEN THE EARTH EQUATOR AND THE ECLIPTIC. THE
042141,000031: # SECOND ANGLE IS THE LONGITUDE OF THE SUN MEASURED IN THE ECLIPTIC.
042142,000032: # THE POSITION VECTOR OF THE SUN IS
042143,000033: # -
042144,000034: # S = (COS(LOS), COS(OBL)*SIN(LOS), SIN(OBL)*SIN(LOS)), WHERE
042145,000035:
042146,000036: # LOS = LOS +LOS *T-(C *SIN(2PI*T)/365.24 +C *COS(2PI*T)/365.24)
042147,000037: # 0 R 0 1
042148,000038: # LOS (RAD) IS THE LONGITUDE OF THE SUN FOR MIDNIGHT JUNE 30TH OF THE PARTICULAR YEAR.
042149,000039: # 0
042150,000040: # LOS (RAD/DAY) IS THE MEAN RATE FOR THE PARTICULAR YEAR.
042151,000041: # R
042152,000042: # LOS AND LOS ARE STORED AS LOSC AND LOSR IN RATESP.
042153,000043: # 0 R
042154,000044: # COS(OBL) AND SIN(OBL) ARE STORED IN THE MATRIX KONMAT.
042155,000045: # T, TIME MEASURED IN DAYS (24 HOURS), IS STORED IN TIMEP.
042156,000046: # C AND C ARE FUDGE FACTORS TO MINIMIZE THE DEVIATION. THEY ARE STORED AS ONE CONSTANT (CMOD), SINCE
042157,000047: # 0 1 2 2 1/2
042158,000048: # C *SIN(X)+C *COS(X) CAN BE WRITTEN AS (C +C ) *SIN(X+PHI), WHERE PHI=ARCTAN(C /C ).
042159,000049: # 0 1 0 1 1 0
042160,000050:
042161,000051: # THE MOON IS LOCATED VIA FOUR ANGLES. THE FIRST IS THE OBLIQUITY. THE SECOND IS THE MEAN LONGITUDE OF THE MOON,
042162,000052: # MEASURED IN THE ECLIPTIC FROM THE MEAN EQUINOX TO THE MEAN ASCENDING NODE OF THE LUNAR ORBIT, AND THEN ALONG THE
042163,000053: # ORBIT. THE THIRD ANGLE IS THE ANGLE BETWEEN THE ECLIPTIC AND THE LUNAR ORBIT. THE FOURTH ANGLE IS THE LONGITUDE
042164,000054: # OF THE NODE OF THE MOON, MEASURED IN THE LUNAR ORBIT. LET THESE ANGLES BE OBL,LOM,IM, AND LON RESPECTIVELY.
042165,000055:
042166,000056: # THE SIMPLIFIED POSITION VECTOR OF THE MOON IS
042167,000057: # -
042168,000058: # 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))
042169,000059:
042170,000060: # WHERE
042171,000061: # 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
042172,000062: # 0 R 0 1 0 1
042173,000063: # LON=LON +LON
042174,000064: # 0 R
042175,000065: # A , A , B AND B ARE STORED AS AMOD AND BMOD (SEE DESCRIPTION OF CMOD, ABOVE). COS(OBL), SIN(OBL)*SIN(IM),
042176,000066: # 0 1 0 1
042177,000067: # SIN(OBL), AND COS(OBL)*SIN(IM) ARE STORED IN KONMAT AS K1, K2, K3 AND K4, RESPECTIVELY. LOM , LOM , LON , LON
042178,000068: # ARE STORED AS LOMO, LOMR, LONO, AND LONR IN RATESP. 0 R 0 R
042179,000069: # THE THREE PHIS ARE STORED AS AARG, BARG, AND CARG(SUN). ALL CONSTANTS ARE UPDATED BY YEAR.
042180,000070:
042181,000071: # CALLING SEQUENCE
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Page 977 |
042183,000073: # CALL LSPOS. RETURN IS VIA CPRET.
042184,000074:
042185,000075: # ALARMS OR ABORTS
042186,000076: # NONE
042187,000077:
042188,000078: # ERASABLE INITIALIZATION REQUIRED
042189,000079: # TEPHEM - TIME FROM MIDNIGHT 1 JULY PRECEDING THE LAUNCH TO THE TIME OF THE LAUNCH (WHEN THE AGC CLOCK WENT
042190,000080: # TO ZERO). TEPHEM IS TP WITH UNITS OF CENTI-SECONDS.
042191,000081: # TIME2 AND TIME1 ARE IN MPAC AND MPAC +1 WHEN PROGRAM IS CALLED.
042192,000082:
042193,000083: # OUTPUT
042194,000084: # UNIT POSITIONAL VECTOR OF SUN IN VSUN. (SCALED B-1)
042195,000085: # UNIT POSITIONAL VECTOR OF MOON IN VMOON. (SCALED B-1)
042196,000086:
042197,000087: # SUBROUTINES USED
042198,000088: # NONE
042199,000089:
042200,000090: # DEBRIS
042201,000091: # CURRENT CORE SET, WORK AREA AND FREEFLAG
042202,000092:
042203,000093: 04,3011 BANK 04
042204,000094: 15,2000 SETLOC EPHEM
042205,000095: 15,2000 BANK
042206,000096:
042207,000097: 15,3647 E5,1714 EBANK= VSUN
042208,000098: 15,3647 COUNT* $$/EPHEM
042209,000099: 15,3647 15,3647 LUNPOS EQUALS LSPOS
042210,000100:
042211,000101: 15,3647 54201 LSPOS SETPD SR
042212,000102: 15,3650 00001 0
042213,000103: 15,3651 20617 14D # TP
042214,000104: 15,3652 56371 TAD DDV
042215,000105: 15,3653 01707 TEPHEM # TIME OF LAUNCH
042216,000106: 15,3654 12024 CSTODAY # 24 HOURS-8640000 CENTI-SECS/DAY B-33
042217,000107: 15,3655 00031 STORE TIMEP # T IN DAYS
042218,000108: 15,3656 77170 AXT,1 AXT,2
042219,000109: 15,3657 00000 0
042220,000110: 15,3660 00000 0
042221,000111: 15,3661 77614 CLEAR
042222,000112: 15,3662 00274 FREEFLAG # SWITCH BIT
042223,000113: 15,3663 77745 POSITA DLOAD
042224,000114: 15,3664 12004 KONMAT +2 # ZEROS
042225,000115: 15,3665 00027 STORE GTMP
042226,000116: 15,3666 40745 POSITB DLOAD DMP*
042227,000117: 15,3667 00031 TIMEP # T
042228,000118: 15,3670 12050 VAL67 +4,1 # 1/27 OR 1/32 OR 1/365
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Page 978 |
042230,000120: 15,3671 42661 SL DAD*
042231,000121: 15,3672 20211 8D
042232,000122: 15,3673 12046 VAL67 +2,1 # AARG
042233,000123: 15,3674 40756 SIN DMP* # SIN(T/27+PHI) OR T/32 OR T/365
042234,000124: 15,3675 12044 VAL67,1 # (A0**2+A1**2)**1/2 SIN(X+PHIA)
042235,000125: 15,3676 62015 DAD INCR,1 # PLUS
042236,000126: 15,3677 00027 GTMP # (B0**2+B1**2)**1/2 SIN(X+PHIB)
042237,000127: 15,3700 77771 DEC -6 B-14
042238,000128: 15,3701 00027 STORE GTMP # OR (C0**2+C1**2)**1/2 SIN(X+PHIC)
042239,000129: 15,3702 77614 BOFSET
042240,000130: 15,3703 00054 FREEFLAG
042241,000131: 15,3704 33666 POSITB
042242,000132: 15,3705 40745 POSITD DLOAD DMP*
042243,000133: 15,3706 00031 TIMEP # T
042244,000134: 15,3707 65747 RATESP,2 # LOMR,LOSR,LONR
042245,000135: 15,3710 42661 SL DAD*
042246,000136: 15,3711 20206 5D
042247,000137: 15,3712 65741 RATESP +6,2 # LOMO,LOSO,LONO
042248,000138: 15,3713 77625 DSU
042249,000139: 15,3714 00027 GTMP
042250,000140: 15,3715 10021 STORE STMP,2 # LOM,LOS,LON
042251,000141: 15,3716 63135 SLOAD INCR,2
042252,000142: 15,3717 00050 X2
042253,000143: 15,3720 77775 DEC -2 B-14
042254,000144: 15,3721 53015 DAD BZE
042255,000145: 15,3722 12026 RCB-13 # PLUS 2
042256,000146: 15,3723 33753 POSITE # 2ND
042257,000147: 15,3724 77644 BPL
042258,000148: 15,3725 33663 POSITA # 1ST
042259,000149: 15,3726 45345 POSITF DLOAD DSU # 3RD
042260,000150: 15,3727 00021 STMP # LOM
042261,000151: 15,3730 00025 STMP +4 # LON
042262,000152: 15,3731 65356 SIN PDDL # SIN(LOM-LON)
042263,000153: 15,3732 00021 STMP
042264,000154: 15,3733 65356 SIN PDDL # SIN LOM
042265,000155: 15,3734 00021 STMP
042266,000156: 15,3735 55546 COS VDEF # COS LOM
042267,000157: 15,3736 53521 MXV UNIT
042268,000158: 15,3737 12002 KONMAT # K1,K2,K3,K4,
042269,000159: 15,3740 02723 STORE VMOON
042270,000160: 15,3741 65345 DLOAD PDDL
042271,000161: 15,3742 12004 KONMAT +2 # ZERO
042272,000162: 15,3743 00023 STMP +2
042273,000163: 15,3744 65356 SIN PDDL # SIN LOS
042274,000164: 15,3745 00023 STMP +2
042275,000165: 15,3746 55546 COS VDEF # COS LOS
042276,000166: 15,3747 53521 MXV UNIT
042277,000167: 15,3750 12002 KONMAT
042278,000168: 15,3751 02715 STORE VSUN
042279,000169: 15,3752 77616 RVQ
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Page 979 |
042281,000171: 15,3753 77745 POSITE DLOAD
042282,000172: 15,3754 12004 KONMAT +2 # ZEROS
042283,000173: 15,3755 00027 STORE GTMP
042284,000174: 15,3756 77650 GOTO
042285,000175: 15,3757 33705 POSITD
042286,000176: 05,2000 SETLOC EPHEM1
042287,000177: 05,2000 BANK
042288,000178:
042289,000179: 05,3472 COUNT* $$/EPHEM
042290,000180:
042291,000181: 05,3472 STMP EQUALS 16D
042292,000182:
042293,000183: 05,3472 GTMP EQUALS 22D
042294,000184:
042295,000185: 05,3472 TIMEP EQUALS 24D
042296,000186:
End of include-file LUNAR_AND_SOLAR_EPHEMERIDES_SUBROUTINES.agc. Parent file is MAIN.agc