Source Code
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These source-code files were from the printout at the MIT Museum, with many thanks
to Deborah Douglas, the Museum's Curator of Science and Technology, for releasing
it to us. The printout was digitally photographed by Paul Fjeld. A team of
volunteers transcribed the source code manually from these images or, where
appropriate, modified already-transcribed but similar source Luminary 131 (Apollo 13)
source code to agree with the images from the printout. Note that the page images
presented online are of reduced quality, and that higher-quality images
are available. Report any conversion errors or legibility
problems in page images to info@sandroid.org.
Notations on the program listing read, in part:GAP: ASSEMBLE REVISION 001 OF AGC PROGRAM LMY99 BY NASA 2021112-061 20'35 OCT. 28,1968Note that the date is the date of the printout, not the date of the program revision. |
042842,000002: ## Copyright: Public domain.
042843,000003: ## Filename: LUNAR_AND_SOLAR_EPHEMERIDES_SUBROUTINES.agc
042844,000004: ## Purpose: Part of the source code for Luminary 1A build 099.
042845,000005: ## It is part of the source code for the Lunar Module's (LM)
042846,000006: ## Apollo Guidance Computer (AGC), for Apollo 11.
042847,000007: ## Assembler: yaYUL
042848,000008: ## Contact: Hartmuth Gutsche <hgutsche@xplornet.com>.
042849,000009: ## Website: www.ibiblio.org/apollo.
042850,000010: ## Pages: 984-987
042851,000011: ## Mod history: 2009-05-24 HG Transcribed from page images.
042852,000012: ## 2016-12-17 RSB Proofed text comments with octopus/ProoferComments
042853,000013: ## and corrected the errors found.
042854,000014: ## 2017-03-13 RSB Comment-text fixes noted in proofing Luminary 116.
042855,000015: ##
042856,000016: ## This source code has been transcribed or otherwise adapted from
042857,000017: ## digitized images of a hardcopy from the MIT Museum. The digitization
042858,000018: ## was performed by Paul Fjeld, and arranged for by Deborah Douglas of
042859,000019: ## the Museum. Many thanks to both. The images (with suitable reduction
042860,000020: ## in storage size and consequent reduction in image quality as well) are
042861,000021: ## available online at www.ibiblio.org/apollo. If for some reason you
042862,000022: ## find that the images are illegible, contact me at info@sandroid.org
042863,000023: ## about getting access to the (much) higher-quality images which Paul
042864,000024: ## actually created.
042865,000025: ##
042866,000026: ## Notations on the hardcopy document read, in part:
042867,000027: ##
042868,000028: ## Assemble revision 001 of AGC program LMY99 by NASA 2021112-61
042869,000029: ## 16:27 JULY 14, 1969
042870,000030:
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Page 984 |
042872,000032: # NAME - LSPOS - LOCATE SUN AND MOON DATE - 25 OCT 67
042873,000033: # MOD NO. 1
042874,000034: # MOD BY NEVILLE ASSEMBLY SUNDANCE
042875,000035:
042876,000036: # FUNCTIONAL DESCRIPTION
042877,000037:
042878,000038: # COMPUTES UNIT POSITION VECTOR OF THE SUN AND MOON IN THE BASIC REFERENCE SYSTEM. THE SUN VECTOR S IS
042879,000039: # LOCATED VIA TWO ANGLES. THE FIRST ANGLE(OBLIQUITY) IS THE ANGLE BETWEEN THE EARTH EQUATOR AND THE ECLIPTIC. THE
042880,000040: # SECOND ANGLE IS THE LONGITUDE OF THE SUN MEASURED IN THE ECLIPTIC.
042881,000041: # THE POSITION VECTOR OF THE SUN IS
042882,000042: # -
042883,000043: # S = (COS(LOS), COS(OBL)*SIN(LOS), SIN(OBL)*SIN(LOS)), WHERE
042884,000044:
042885,000045: # LOS = LOS +LOS *T-(C *SIN(2PI*T)/365.24 +C *COS(2PI*T)/365.24)
042886,000046: # 0 R 0 1
042887,000047: # LOS (RAD) IS THE LONGITUDE OF THE SUN FOR MIDNIGHT JUNE 30TH OF THE PARTICULAR YEAR.
042888,000048: # 0
042889,000049: # LOS (RAD/DAY) IS THE MEAN RATE FOR THE PARTICULAR YEAR.
042890,000050: # R
042891,000051:
042892,000052: # LOS AND LOS ARE STORED AS LOSC AND LOSR IN RATESP.
042893,000053: # 0 R
042894,000054: # COS(OBL) AND SIN(OBL) ARE STORED IN THE MATRIX KONMAT.
042895,000055:
042896,000056: # T, TIME MEASURED IN DAYS (24 HOURS), IS STORED IN TIMEP.
042897,000057:
042898,000058: # C AND C ARE FUDGE FACTORS TO MINIMIZE THE DEVIATION. THEY ARE STORED AS ONE CONSTANT (CMOD), SINCE
042899,000059: # 0 1 2 2 1/2
042900,000060: # C *SIN(X)+C *COS(X) CAN BE WRITTEN AS (C +C ) *SIN(X+PHI), WHERE PHI=ARCTAN(C /C ).
042901,000061: # 0 1 0 1 1 0
042902,000062:
042903,000063: # THE MOON IS LOCATED VIA FOUR ANGLES, THE FIRST IS THE OBLIQUITY. THE SECOND IS THE MEAN LONGITUDE OF THE MOON,
042904,000064: # MEASURED IN THE ECLIPTIC FROM THE MEAN EQUINOX TO THE MEAN ASCENDING NODE OF THE LUNAR ORBIT, AND THEN ALONG THE
042905,000065: # ORBIT. THE THIRD ANGLE IS THE ANGLE BETWEEN THE ECLIPTIC AND THE LUNAR ORBIT. THE FOURTH ANGLE IS THE LONGITUDE
042906,000066: # OF THE NODE OF THE MOON, MEASURED IN THE LUNAR ORBIT. LET THESE ANGLES BE OBL,LOM,IM, AND LON RESPECTIVELY.
042907,000067:
042908,000068: # THE SIMPLIFIED POSITION VECTOR OF THE MOON IS
042909,000069: # -
042910,000070: # 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))
042911,000071:
042912,000072: # WHERE
042913,000073: # 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
042914,000074: # 0 R 0 1 0 1
042915,000075: # LON=LON +LON
042916,000076: # 0 R
042917,000077: # A , A , B AND B ARE STORED AS AMOD AND BMOD (SEE DESCRIPTION OF CMOD, ABOVE). COS(OBL), SIN(OBL)*SIN(IM),
042918,000078: # 0 1 0 1
042919,000079: # SIN(OBL), AND COS(OBL)*SIN(IM) ARE STORED IN KONMAT AS K1, K2, K3 AND K4, RESPECTIVELY. LOM , LOM , LON , LON
042920,000080: # ARE STORED AS LOM0, LOMR, LON0, AND LONR IN RATESP. 0 R 0 R
042921,000081: # THE THREE PHIS ARE STORED AS AARG, BARG, AND CARG(SUN). ALL CONSTANTS ARE UPDATED BY YEAR.
042922,000082:
042923,000083: # CALLING SEQUENCE
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Page 985 |
042925,000085: # CALL LSPOS. RETURN IS VIA CPRET.
042926,000086:
042927,000087: # ALARMS OR ABORTS
042928,000088: # NONE
042929,000089:
042930,000090: # ERASABLE INITIALIZATION REQUIRED
042931,000091: # TEPHEM - TIME FROM MIDNIGHT 1 JULY PRECEDING THE LAUNCH TO THE TIME OF THE LAUNCH (WHEN THE AGC CLOCK WENT
042932,000092: # TO ZERO). TEPHEM IS TP WITH UNITS OF CENTI-SECONDS.
042933,000093:
042934,000094: # TIME2 AND TIME1 ARE IN MPAC AND MPAC +1 WHEN PROGRAM IS CALLED.
042935,000095:
042936,000096: # OUTPUT
042937,000097: # UNIT POSITIONAL VECTOR OF SUN IN VSUN. (SCALED B-1)
042938,000098: # UNIT POSITIONAL VECTOR OF MOON IN VMOON. (SCALED B-1)
042939,000099:
042940,000100: # SUBROUTINES USED
042941,000101: # NONE
042942,000102:
042943,000103: # DEBRIS
042944,000104: # CURRENT CORE SET, WORK AREA AND FREEFLAG
042945,000105:
042946,000106: 04,3027 BANK 04
042947,000107: 15,2000 SETLOC EPHEM
042948,000108: 15,2000 BANK
042949,000109:
042950,000110: 15,3664 E5,1714 EBANK= VSUN
042951,000111: 15,3664 COUNT* $$/EPHEM
042952,000112: 15,3664 15,3664 LUNPOS EQUALS LSPOS
042953,000113:
042954,000114: 15,3664 54201 LSPOS SETPD SR
042955,000115: 15,3665 00001 0
042956,000116: 15,3666 20617 14D # TP
042957,000117: 15,3667 56371 TAD DDV
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The hand-written notation "in centisec B 42" appears to the right. |
042959,000119: 15,3670 01707 TEPHEM # TIME OF LAUNCH
042960,000120: 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. |
042962,000122: 15,3672 00031 STORE TIMEP # T IN DAYS
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The hand-written notation "∴ granularity ≈ 0.164 sec" appears to the right. |
042964,000124: 15,3673 77170 AXT,1 AXT,2
042965,000125: 15,3674 00000 0
042966,000126: 15,3675 00000 0
042967,000127: 15,3676 77614 CLEAR
042968,000128: 15,3677 00274 FREEFLAG # SWITCH BIT
042969,000129: 15,3700 77745 POSITA DLOAD
042970,000130: 15,3701 12004 KONMAT +2 # ZEROS
042971,000131: 15,3702 00027 STORE GTMP
042972,000132: 15,3703 40745 POSITB DLOAD DMP*
042973,000133: 15,3704 00031 TIMEP # T
042974,000134: 15,3705 12050 VAL67 +4,1 # 1/27 OR 1/32 OR 1/365
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Page 986 |
042976,000136: 15,3706 42661 SL DAD*
042977,000137: 15,3707 20211 8D
042978,000138: 15,3710 12046 VAL67 +2,1 # AARG
042979,000139: 15,3711 40756 SIN DMP* # SIN(T/27+PHI) OR T/32 OR T/365
042980,000140: 15,3712 12044 VAL67,1 # (A0**2+A1**2)**1/2 SIN(X+PHIA)
042981,000141: 15,3713 62015 DAD INCR,1 # PLUS
042982,000142: 15,3714 00027 GTMP # (B0**2+B1**2)**1/2 SIN(X+PHIB)
042983,000143: 15,3715 77771 DEC -6 B-14
042984,000144: 15,3716 00027 STORE GTMP # OR (C0**2+C1**2)**1/2 SIN(X+PHIC)
042985,000145: 15,3717 77614 BOFSET
042986,000146: 15,3720 00054 FREEFLAG
042987,000147: 15,3721 33703 POSITB
042988,000148: 15,3722 40745 POSITD DLOAD DMP*
042989,000149: 15,3723 00031 TIMEP # T
042990,000150: 15,3724 65747 RATESP,2 # LOMR,LOSR,LONR
042991,000151: 15,3725 42661 SL DAD*
042992,000152: 15,3726 20206 5D
042993,000153: 15,3727 65741 RATESP +6,2 # LOMO,LOSO,LONO
042994,000154: 15,3730 77625 DSU
042995,000155: 15,3731 00027 GTMP
042996,000156: 15,3732 10021 STORE STMP,2 # LOM,LOS,LON
042997,000157: 15,3733 63135 SLOAD INCR,2
042998,000158: 15,3734 00050 X2
042999,000159: 15,3735 77775 DEC -2 B-14
043000,000160: 15,3736 53015 DAD BZE
043001,000161: 15,3737 12026 RCB-13 # PLUS 2
043002,000162: 15,3740 33770 POSITE # 2ND
043003,000163: 15,3741 77644 BPL
043004,000164: 15,3742 33700 POSITA # 1ST
043005,000165: 15,3743 45345 POSITF DLOAD DSU # 3RD
043006,000166: 15,3744 00021 STMP # LOM
043007,000167: 15,3745 00025 STMP +4 # LON
043008,000168: 15,3746 65356 SIN PDDL # SIN(LOM-LON)
043009,000169: 15,3747 00021 STMP
043010,000170: 15,3750 65356 SIN PDDL # SIN LOM
043011,000171: 15,3751 00021 STMP
043012,000172: 15,3752 55546 COS VDEF # COS LOM
043013,000173: 15,3753 53521 MXV UNIT
043014,000174: 15,3754 12002 KONMAT # K1,K2,K3,K4,
043015,000175: 15,3755 02723 STORE VMOON
043016,000176: 15,3756 65345 DLOAD PDDL
043017,000177: 15,3757 12004 KONMAT +2 # ZERO
043018,000178: 15,3760 00023 STMP +2
043019,000179: 15,3761 65356 SIN PDDL # SIN LOS
043020,000180: 15,3762 00023 STMP +2
043021,000181: 15,3763 55546 COS VDEF # COS LOS
043022,000182: 15,3764 53521 MXV UNIT
043023,000183: 15,3765 12002 KONMAT
043024,000184: 15,3766 02715 STORE VSUN
043025,000185: 15,3767 77616 RVQ
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Page 987 |
043027,000187: 15,3770 77745 POSITE DLOAD
043028,000188: 15,3771 12004 KONMAT +2 # ZEROS
043029,000189: 15,3772 00027 STORE GTMP
043030,000190: 15,3773 77650 GOTO
043031,000191: 15,3774 33722 POSITD
043032,000192: 15,3775 77616 LUNVEL RVQ # TO FOOL INTEGRATION
043033,000193: 05,2000 SETLOC EPHEM1
043034,000194: 05,2000 BANK
043035,000195:
043036,000196: 05,3506 COUNT* $$/EPHEM
043037,000197: 05,3506 STMP EQUALS 16D
043038,000198: 05,3506 GTMP EQUALS 22D
043039,000199: 05,3506 TIMEP EQUALS 24D
043040,000200:
End of include-file LUNAR_AND_SOLAR_EPHEMERIDES_SUBROUTINES.agc. Parent file is MAIN.agc