Source Code
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This is an attempt to recreate Luminary 99 Rev 2, otherwise known as LUM99R2, from Luminary 99 Rev 1 and ephemeris data from Luminary 116. The differences are confined to the last 10-12 lines of the CONTROLLED CONSTANTS. Luminary 99 Rev 1 source-code was transcribed from a printout in the MIT Museum, while Luminary 116 source code was transcribed from a printout belonging to Don Eyles. AGC developer James Kernan, the "rope mother" for the Apollo 11 Lunar Module's AGC, explains as follows: "At the last minute, Dan Lickly, our chief engineer, appeared with ephemerides updates and it took two tries to get it right. The result was that we created Lum99 Revision 1 and Lum99 Revision 2." It is suspected that the former is what's in the MIT Museum, and the latter is what we are trying to recreate here. As for which revision actually flew in Apollo 11, all of the other available surviving evidence points to Rev 1 rather than to Rev 2, so we're just not sure! |
042099,000002: ## Copyright: Public domain.
042100,000003: ## Filename: LUNAR_AND_SOLAR_EPHEMERIDES_SUBROUTINES.agc
042101,000004: ## Purpose: Part of the source code for Luminary 1A build 099.
042102,000005: ## It is part of the source code for the Lunar Module's (LM)
042103,000006: ## Apollo Guidance Computer (AGC), for Apollo 11.
042104,000007: ## Assembler: yaYUL
042105,000008: ## Contact: Hartmuth Gutsche <hgutsche@xplornet.com>.
042106,000009: ## Website: www.ibiblio.org/apollo.
042107,000010: ## Pages: 984-987
042108,000011: ## Mod history: 2009-05-24 HG Transcribed from page images.
042109,000012: ## 2016-12-17 RSB Proofed text comments with octopus/ProoferComments
042110,000013: ## and corrected the errors found.
042111,000014: ## 2017-03-03 RSB Snapshot of Luminary 99 Rev 1.
042112,000015: ## 2017-03-13 RSB Comment-text fixes noted in proofing Luminary 116.
042113,000016: ## 2017-08-26 MAS Fixed comment-text errors found while transcribing Zerlina 56.
042114,000017:
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Page 984 |
042116,000019: # NAME - LSPOS - LOCATE SUN AND MOON DATE - 25 OCT 67
042117,000020: # MOD NO. 1
042118,000021: # MOD BY NEVILLE ASSEMBLY SUNDANCE
042119,000022:
042120,000023: # FUNCTIONAL DESCRIPTION
042121,000024:
042122,000025: # COMPUTES UNIT POSITION VECTOR OF THE SUN AND MOON IN THE BASIC REFERENCE SYSTEM. THE SUN VECTOR S IS
042123,000026: # LOCATED VIA TWO ANGLES. THE FIRST ANGLE(OBLIQUITY) IS THE ANGLE BETWEEN THE EARTH EQUATOR AND THE ECLIPTIC. THE
042124,000027: # SECOND ANGLE IS THE LONGITUDE OF THE SUN MEASURED IN THE ECLIPTIC.
042125,000028: # THE POSITION VECTOR OF THE SUN IS
042126,000029: # -
042127,000030: # S = (COS(LOS), COS(OBL)*SIN(LOS), SIN(OBL)*SIN(LOS)), WHERE
042128,000031:
042129,000032: # LOS = LOS +LOS *T-(C *SIN(2PI*T)/365.24 +C *COS(2PI*T)/365.24)
042130,000033: # 0 R 0 1
042131,000034: # LOS (RAD) IS THE LONGITUDE OF THE SUN FOR MIDNIGHT JUNE 30TH OF THE PARTICULAR YEAR.
042132,000035: # 0
042133,000036: # LOS (RAD/DAY) IS THE MEAN RATE FOR THE PARTICULAR YEAR.
042134,000037: # R
042135,000038:
042136,000039: # LOS AND LOS ARE STORED AS LOSC AND LOSR IN RATESP.
042137,000040: # 0 R
042138,000041: # COS(OBL) AND SIN(OBL) ARE STORED IN THE MATRIX KONMAT.
042139,000042:
042140,000043: # T, TIME MEASURED IN DAYS (24 HOURS), IS STORED IN TIMEP.
042141,000044:
042142,000045: # C AND C ARE FUDGE FACTORS TO MINIMIZE THE DEVIATION. THEY ARE STORED AS ONE CONSTANT (CMOD), SINCE
042143,000046: # 0 1 2 2 1/2
042144,000047: # C *SIN(X)+C *COS(X) CAN BE WRITTEN AS (C +C ) *SIN(X+PHI), WHERE PHI=ARCTAN(C /C ).
042145,000048: # 0 1 0 1 1 0
042146,000049:
042147,000050: # THE MOON IS LOCATED VIA FOUR ANGLES. THE FIRST IS THE OBLIQUITY. THE SECOND IS THE MEAN LONGITUDE OF THE MOON,
042148,000051: # MEASURED IN THE ECLIPTIC FROM THE MEAN EQUINOX TO THE MEAN ASCENDING NODE OF THE LUNAR ORBIT, AND THEN ALONG THE
042149,000052: # ORBIT. THE THIRD ANGLE IS THE ANGLE BETWEEN THE ECLIPTIC AND THE LUNAR ORBIT. THE FOURTH ANGLE IS THE LONGITUDE
042150,000053: # OF THE NODE OF THE MOON, MEASURED IN THE LUNAR ORBIT. LET THESE ANGLES BE OBL,LOM,IM, AND LON RESPECTIVELY.
042151,000054:
042152,000055: # THE SIMPLIFIED POSITION VECTOR OF THE MOON IS
042153,000056: # -
042154,000057: # 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))
042155,000058:
042156,000059: # WHERE
042157,000060: # 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
042158,000061: # 0 R 0 1 0 1
042159,000062: # LON=LON +LON
042160,000063: # 0 R
042161,000064: # A , A , B AND B ARE STORED AS AMOD AND BMOD (SEE DESCRIPTION OF CMOD, ABOVE). COS(OBL), SIN(OBL)*SIN(IM),
042162,000065: # 0 1 0 1
042163,000066: # SIN(OBL), AND COS(OBL)*SIN(IM) ARE STORED IN KONMAT AS K1, K2, K3 AND K4, RESPECTIVELY. LOM , LOM , LON , LON
042164,000067: # ARE STORED AS LOMO, LOMR, LONO, AND LONR IN RATESP. 0 R 0 R
042165,000068: # THE THREE PHIS ARE STORED AS AARG, BARG, AND CARG(SUN). ALL CONSTANTS ARE UPDATED BY YEAR.
042166,000069:
042167,000070: # CALLING SEQUENCE
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Page 985 |
042169,000072: # CALL LSPOS. RETURN IS VIA CPRET.
042170,000073:
042171,000074: # ALARMS OR ABORTS
042172,000075: # NONE
042173,000076:
042174,000077: # ERASABLE INITIALIZATION REQUIRED
042175,000078: # TEPHEM - TIME FROM MIDNIGHT 1 JULY PRECEDING THE LAUNCH TO THE TIME OF THE LAUNCH (WHEN THE AGC CLOCK WENT
042176,000079: # TO ZERO). TEPHEM IS TP WITH UNITS OF CENTI-SECONDS.
042177,000080:
042178,000081: # TIME2 AND TIME1 ARE IN MPAC AND MPAC +1 WHEN PROGRAM IS CALLED.
042179,000082:
042180,000083: # OUTPUT
042181,000084: # UNIT POSITIONAL VECTOR OF SUN IN VSUN. (SCALED B-1)
042182,000085: # UNIT POSITIONAL VECTOR OF MOON IN VMOON. (SCALED B-1)
042183,000086:
042184,000087: # SUBROUTINES USED
042185,000088: # NONE
042186,000089:
042187,000090: # DEBRIS
042188,000091: # CURRENT CORE SET, WORK AREA AND FREEFLAG
042189,000092:
042190,000093: 04,3027 BANK 04
042191,000094: 15,2000 SETLOC EPHEM
042192,000095: 15,2000 BANK
042193,000096:
042194,000097: 15,3664 E5,1714 EBANK= VSUN
042195,000098: 15,3664 COUNT* $$/EPHEM
042196,000099: 15,3664 15,3664 LUNPOS EQUALS LSPOS
042197,000100:
042198,000101: 15,3664 54201 LSPOS SETPD SR
042199,000102: 15,3665 00001 0
042200,000103: 15,3666 20617 14D # TP
042201,000104: 15,3667 56371 TAD DDV
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The hand-written notation "in centisec B 42" appears to the right. |
042203,000106: 15,3670 01707 TEPHEM # TIME OF LAUNCH
042204,000107: 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. |
042206,000109: 15,3672 00031 STORE TIMEP # T IN DAYS
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The hand-written notation "∴ granularity ≈ 0.164 sec" appears to the right. |
042208,000111: 15,3673 77170 AXT,1 AXT,2
042209,000112: 15,3674 00000 0
042210,000113: 15,3675 00000 0
042211,000114: 15,3676 77614 CLEAR
042212,000115: 15,3677 00274 FREEFLAG # SWITCH BIT
042213,000116: 15,3700 77745 POSITA DLOAD
042214,000117: 15,3701 12004 KONMAT +2 # ZEROS
042215,000118: 15,3702 00027 STORE GTMP
042216,000119: 15,3703 40745 POSITB DLOAD DMP*
042217,000120: 15,3704 00031 TIMEP # T
042218,000121: 15,3705 12050 VAL67 +4,1 # 1/27 OR 1/32 OR 1/365
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Page 986 |
042220,000123: 15,3706 42661 SL DAD*
042221,000124: 15,3707 20211 8D
042222,000125: 15,3710 12046 VAL67 +2,1 # AARG
042223,000126: 15,3711 40756 SIN DMP* # SIN(T/27+PHI) OR T/32 OR T/365
042224,000127: 15,3712 12044 VAL67,1 # (A0**2+A1**2)**1/2 SIN(X+PHIA)
042225,000128: 15,3713 62015 DAD INCR,1 # PLUS
042226,000129: 15,3714 00027 GTMP # (B0**2+B1**2)**1/2 SIN(X+PHIB)
042227,000130: 15,3715 77771 DEC -6 B-14
042228,000131: 15,3716 00027 STORE GTMP # OR (C0**2+C1**2)**1/2 SIN(X+PHIC)
042229,000132: 15,3717 77614 BOFSET
042230,000133: 15,3720 00054 FREEFLAG
042231,000134: 15,3721 33703 POSITB
042232,000135: 15,3722 40745 POSITD DLOAD DMP*
042233,000136: 15,3723 00031 TIMEP # T
042234,000137: 15,3724 65747 RATESP,2 # LOMR,LOSR,LONR
042235,000138: 15,3725 42661 SL DAD*
042236,000139: 15,3726 20206 5D
042237,000140: 15,3727 65741 RATESP +6,2 # LOMO,LOSO,LONO
042238,000141: 15,3730 77625 DSU
042239,000142: 15,3731 00027 GTMP
042240,000143: 15,3732 10021 STORE STMP,2 # LOM,LOS,LON
042241,000144: 15,3733 63135 SLOAD INCR,2
042242,000145: 15,3734 00050 X2
042243,000146: 15,3735 77775 DEC -2 B-14
042244,000147: 15,3736 53015 DAD BZE
042245,000148: 15,3737 12026 RCB-13 # PLUS 2
042246,000149: 15,3740 33770 POSITE # 2ND
042247,000150: 15,3741 77644 BPL
042248,000151: 15,3742 33700 POSITA # 1ST
042249,000152: 15,3743 45345 POSITF DLOAD DSU # 3RD
042250,000153: 15,3744 00021 STMP # LOM
042251,000154: 15,3745 00025 STMP +4 # LON
042252,000155: 15,3746 65356 SIN PDDL # SIN(LOM-LON)
042253,000156: 15,3747 00021 STMP
042254,000157: 15,3750 65356 SIN PDDL # SIN LOM
042255,000158: 15,3751 00021 STMP
042256,000159: 15,3752 55546 COS VDEF # COS LOM
042257,000160: 15,3753 53521 MXV UNIT
042258,000161: 15,3754 12002 KONMAT # K1,K2,K3,K4,
042259,000162: 15,3755 02723 STORE VMOON
042260,000163: 15,3756 65345 DLOAD PDDL
042261,000164: 15,3757 12004 KONMAT +2 # ZERO
042262,000165: 15,3760 00023 STMP +2
042263,000166: 15,3761 65356 SIN PDDL # SIN LOS
042264,000167: 15,3762 00023 STMP +2
042265,000168: 15,3763 55546 COS VDEF # COS LOS
042266,000169: 15,3764 53521 MXV UNIT
042267,000170: 15,3765 12002 KONMAT
042268,000171: 15,3766 02715 STORE VSUN
042269,000172: 15,3767 77616 RVQ
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Page 987 |
042271,000174: 15,3770 77745 POSITE DLOAD
042272,000175: 15,3771 12004 KONMAT +2 # ZEROS
042273,000176: 15,3772 00027 STORE GTMP
042274,000177: 15,3773 77650 GOTO
042275,000178: 15,3774 33722 POSITD
042276,000179: 15,3775 77616 LUNVEL RVQ # TO FOOL INTEGRATION
042277,000180: 05,2000 SETLOC EPHEM1
042278,000181: 05,2000 BANK
042279,000182:
042280,000183: 05,3506 COUNT* $$/EPHEM
042281,000184: 05,3506 STMP EQUALS 16D
042282,000185: 05,3506 GTMP EQUALS 22D
042283,000186: 05,3506 TIMEP EQUALS 24D
042284,000187:
End of include-file LUNAR_AND_SOLAR_EPHEMERIDES_SUBROUTINES.agc. Parent file is MAIN.agc