Source Code
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These source-code files are part of a reconstructed copy of Luminary 98, a
development version of the Apollo 11 Lunar Module (LM) Apollo Guidance Computer
(AGC) software.
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 memo 85, using asterisks
indicating changed lines in the listing as a guide. While no listing of this
version is known to exist, nor are the memory-bank checksums available,
the reconstruction is believed to be correct because it was an an intermediate
step in reconstructing Luminary 97 whose reconstruction was
verified by matching memory-bank checksums to those listed in drawing 2021152G.
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 98 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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041875,000002: ## Copyright: Public domain.
041876,000003: ## Filename: LUNAR_AND_SOLAR_EPHEMERIDES_SUBROUTINES.agc
041877,000004: ## Purpose: A section of Luminary revision 98.
041878,000005: ## It is part of the reconstructed source code for the a
041879,000006: ## development version of the flight software for the Lunar
041880,000007: ## Module's (LM) Apollo Guidance Computer (AGC) for Apollo 11.
041881,000008: ## The code has been recreated from a copy of Luminary 99
041882,000009: ## revision 001, using asterisks indicating changed lines in
041883,000010: ## the listing and Luminary Memo #85, which lists changes between
041884,000011: ## Luminary 98 and 99.
041885,000012: ## Reference: pp. 984-987
041886,000013: ## Assembler: yaYUL
041887,000014: ## Contact: Ron Burkey <info@sandroid.org>.
041888,000015: ## Website: www.ibiblio.org/apollo/index.html
041889,000016: ## Mod history: 2019-07-28 MAS Created from Luminary 99.
041890,000017:
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Page 984
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041892,000019: # NAME - LSPOS - LOCATE SUN AND MOON DATE - 25 OCT 67
041893,000020: # MOD NO. 1
041894,000021: # MOD BY NEVILLE ASSEMBLY SUNDANCE
041895,000022:
041896,000023: # FUNCTIONAL DESCRIPTION
041897,000024:
041898,000025: # COMPUTES UNIT POSITION VECTOR OF THE SUN AND MOON IN THE BASIC REFERENCE SYSTEM. THE SUN VECTOR S IS
041899,000026: # LOCATED VIA TWO ANGLES. THE FIRST ANGLE(OBLIQUITY) IS THE ANGLE BETWEEN THE EARTH EQUATOR AND THE ECLIPTIC. THE
041900,000027: # SECOND ANGLE IS THE LONGITUDE OF THE SUN MEASURED IN THE ECLIPTIC.
041901,000028: # THE POSITION VECTOR OF THE SUN IS
041902,000029: # -
041903,000030: # S = (COS(LOS), COS(OBL)*SIN(LOS), SIN(OBL)*SIN(LOS)), WHERE
041904,000031:
041905,000032: # LOS = LOS +LOS *T-(C *SIN(2PI*T)/365.24 +C *COS(2PI*T)/365.24)
041906,000033: # 0 R 0 1
041907,000034: # LOS (RAD) IS THE LONGITUDE OF THE SUN FOR MIDNIGHT JUNE 30TH OF THE PARTICULAR YEAR.
041908,000035: # 0
041909,000036: # LOS (RAD/DAY) IS THE MEAN RATE FOR THE PARTICULAR YEAR.
041910,000037: # R
041911,000038:
041912,000039: # LOS AND LOS ARE STORED AS LOSC AND LOSR IN RATESP.
041913,000040: # 0 R
041914,000041: # COS(OBL) AND SIN(OBL) ARE STORED IN THE MATRIX KONMAT.
041915,000042:
041916,000043: # T, TIME MEASURED IN DAYS (24 HOURS), IS STORED IN TIMEP.
041917,000044:
041918,000045: # C AND C ARE FUDGE FACTORS TO MINIMIZE THE DEVIATION. THEY ARE STORED AS ONE CONSTANT (CMOD), SINCE
041919,000046: # 0 1 2 2 1/2
041920,000047: # C *SIN(X)+C *COS(X) CAN BE WRITTEN AS (C +C ) *SIN(X+PHI), WHERE PHI=ARCTAN(C /C ).
041921,000048: # 0 1 0 1 1 0
041922,000049:
041923,000050: # THE MOON IS LOCATED VIA FOUR ANGLES. THE FIRST IS THE OBLIQUITY. THE SECOND IS THE MEAN LONGITUDE OF THE MOON,
041924,000051: # MEASURED IN THE ECLIPTIC FROM THE MEAN EQUINOX TO THE MEAN ASCENDING NODE OF THE LUNAR ORBIT, AND THEN ALONG THE
041925,000052: # ORBIT. THE THIRD ANGLE IS THE ANGLE BETWEEN THE ECLIPTIC AND THE LUNAR ORBIT. THE FOURTH ANGLE IS THE LONGITUDE
041926,000053: # OF THE NODE OF THE MOON, MEASURED IN THE LUNAR ORBIT. LET THESE ANGLES BE OBL,LOM,IM, AND LON RESPECTIVELY.
041927,000054:
041928,000055: # THE SIMPLIFIED POSITION VECTOR OF THE MOON IS
041929,000056: # -
041930,000057: # 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))
041931,000058:
041932,000059: # WHERE
041933,000060: # 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
041934,000061: # 0 R 0 1 0 1
041935,000062: # LON=LON +LON
041936,000063: # 0 R
041937,000064: # A , A , B AND B ARE STORED AS AMOD AND BMOD (SEE DESCRIPTION OF CMOD, ABOVE). COS(OBL), SIN(OBL)*SIN(IM),
041938,000065: # 0 1 0 1
041939,000066: # SIN(OBL), AND COS(OBL)*SIN(IM) ARE STORED IN KONMAT AS K1, K2, K3 AND K4, RESPECTIVELY. LOM , LOM , LON , LON
041940,000067: # ARE STORED AS LOMO, LOMR, LONO, AND LONR IN RATESP. 0 R 0 R
041941,000068: # THE THREE PHIS ARE STORED AS AARG, BARG, AND CARG(SUN). ALL CONSTANTS ARE UPDATED BY YEAR.
041942,000069:
041943,000070: # CALLING SEQUENCE
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Page 985
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041945,000072: # CALL LSPOS. RETURN IS VIA CPRET.
041946,000073:
041947,000074: # ALARMS OR ABORTS
041948,000075: # NONE
041949,000076:
041950,000077: # ERASABLE INITIALIZATION REQUIRED
041951,000078: # TEPHEM - TIME FROM MIDNIGHT 1 JULY PRECEDING THE LAUNCH TO THE TIME OF THE LAUNCH (WHEN THE AGC CLOCK WENT
041952,000079: # TO ZERO). TEPHEM IS TP WITH UNITS OF CENTI-SECONDS.
041953,000080:
041954,000081: # TIME2 AND TIME1 ARE IN MPAC AND MPAC +1 WHEN PROGRAM IS CALLED.
041955,000082:
041956,000083: # OUTPUT
041957,000084: # UNIT POSITIONAL VECTOR OF SUN IN VSUN. (SCALED B-1)
041958,000085: # UNIT POSITIONAL VECTOR OF MOON IN VMOON. (SCALED B-1)
041959,000086:
041960,000087: # SUBROUTINES USED
041961,000088: # NONE
041962,000089:
041963,000090: # DEBRIS
041964,000091: # CURRENT CORE SET, WORK AREA AND FREEFLAG
041965,000092:
041966,000093: 04,3027 BANK 04
041967,000094: 15,2000 SETLOC EPHEM
041968,000095: 15,2000 BANK
041969,000096:
041970,000097: 15,3664 E5,1714 EBANK= VSUN
041971,000098: 15,3664 COUNT* $$/EPHEM
041972,000099: 15,3664 15,3664 LUNPOS EQUALS LSPOS
041973,000100:
041974,000101: 15,3664 54201 LSPOS SETPD SR
041975,000102: 15,3665 00001 0
041976,000103: 15,3666 20617 14D # TP
041977,000104: 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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041979,000106: 15,3670 01707 TEPHEM # TIME OF LAUNCH
041980,000107: 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.
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041982,000109: 15,3672 00031 STORE TIMEP # T IN DAYS
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The hand-written notation "∴ granularity ≈ 0.164 sec" appears to the right.
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041984,000111: 15,3673 77170 AXT,1 AXT,2
041985,000112: 15,3674 00000 0
041986,000113: 15,3675 00000 0
041987,000114: 15,3676 77614 CLEAR
041988,000115: 15,3677 00274 FREEFLAG # SWITCH BIT
041989,000116: 15,3700 77745 POSITA DLOAD
041990,000117: 15,3701 12004 KONMAT +2 # ZEROS
041991,000118: 15,3702 00027 STORE GTMP
041992,000119: 15,3703 40745 POSITB DLOAD DMP*
041993,000120: 15,3704 00031 TIMEP # T
041994,000121: 15,3705 12050 VAL67 +4,1 # 1/27 OR 1/32 OR 1/365
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Page 986
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041996,000123: 15,3706 42661 SL DAD*
041997,000124: 15,3707 20211 8D
041998,000125: 15,3710 12046 VAL67 +2,1 # AARG
041999,000126: 15,3711 40756 SIN DMP* # SIN(T/27+PHI) OR T/32 OR T/365
042000,000127: 15,3712 12044 VAL67,1 # (A0**2+A1**2)**1/2 SIN(X+PHIA)
042001,000128: 15,3713 62015 DAD INCR,1 # PLUS
042002,000129: 15,3714 00027 GTMP # (B0**2+B1**2)**1/2 SIN(X+PHIB)
042003,000130: 15,3715 77771 DEC -6 B-14
042004,000131: 15,3716 00027 STORE GTMP # OR (C0**2+C1**2)**1/2 SIN(X+PHIC)
042005,000132: 15,3717 77614 BOFSET
042006,000133: 15,3720 00054 FREEFLAG
042007,000134: 15,3721 33703 POSITB
042008,000135: 15,3722 40745 POSITD DLOAD DMP*
042009,000136: 15,3723 00031 TIMEP # T
042010,000137: 15,3724 65747 RATESP,2 # LOMR,LOSR,LONR
042011,000138: 15,3725 42661 SL DAD*
042012,000139: 15,3726 20206 5D
042013,000140: 15,3727 65741 RATESP +6,2 # LOMO,LOSO,LONO
042014,000141: 15,3730 77625 DSU
042015,000142: 15,3731 00027 GTMP
042016,000143: 15,3732 10021 STORE STMP,2 # LOM,LOS,LON
042017,000144: 15,3733 63135 SLOAD INCR,2
042018,000145: 15,3734 00050 X2
042019,000146: 15,3735 77775 DEC -2 B-14
042020,000147: 15,3736 53015 DAD BZE
042021,000148: 15,3737 12026 RCB-13 # PLUS 2
042022,000149: 15,3740 33770 POSITE # 2ND
042023,000150: 15,3741 77644 BPL
042024,000151: 15,3742 33700 POSITA # 1ST
042025,000152: 15,3743 45345 POSITF DLOAD DSU # 3RD
042026,000153: 15,3744 00021 STMP # LOM
042027,000154: 15,3745 00025 STMP +4 # LON
042028,000155: 15,3746 65356 SIN PDDL # SIN(LOM-LON)
042029,000156: 15,3747 00021 STMP
042030,000157: 15,3750 65356 SIN PDDL # SIN LOM
042031,000158: 15,3751 00021 STMP
042032,000159: 15,3752 55546 COS VDEF # COS LOM
042033,000160: 15,3753 53521 MXV UNIT
042034,000161: 15,3754 12002 KONMAT # K1,K2,K3,K4,
042035,000162: 15,3755 02723 STORE VMOON
042036,000163: 15,3756 65345 DLOAD PDDL
042037,000164: 15,3757 12004 KONMAT +2 # ZERO
042038,000165: 15,3760 00023 STMP +2
042039,000166: 15,3761 65356 SIN PDDL # SIN LOS
042040,000167: 15,3762 00023 STMP +2
042041,000168: 15,3763 55546 COS VDEF # COS LOS
042042,000169: 15,3764 53521 MXV UNIT
042043,000170: 15,3765 12002 KONMAT
042044,000171: 15,3766 02715 STORE VSUN
042045,000172: 15,3767 77616 RVQ
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Page 987
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042047,000174: 15,3770 77745 POSITE DLOAD
042048,000175: 15,3771 12004 KONMAT +2 # ZEROS
042049,000176: 15,3772 00027 STORE GTMP
042050,000177: 15,3773 77650 GOTO
042051,000178: 15,3774 33722 POSITD
042052,000179: 15,3775 77616 LUNVEL RVQ # TO FOOL INTEGRATION
042053,000180: 05,2000 SETLOC EPHEM1
042054,000181: 05,2000 BANK
042055,000182:
042056,000183: 05,3506 COUNT* $$/EPHEM
042057,000184: 05,3506 STMP EQUALS 16D
042058,000185: 05,3506 GTMP EQUALS 22D
042059,000186: 05,3506 TIMEP EQUALS 24D
042060,000187:
End of include-file LUNAR_AND_SOLAR_EPHEMERIDES_SUBROUTINES.agc. Parent file is MAIN.agc