GAP: ASSEMBLE REVISION 001 OF AGC PROGRAM LMY99 BY NASA 2021112-061 16:27 JULY 14,1969Note 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 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 16:27 JULY 14,1969Note that the date is the date of the printout, not the date of the program revision. |
042874,000002: ## Copyright: Public domain.
042875,000003: ## Filename: LUNAR_AND_SOLAR_EPHEMERIDES_SUBROUTINES.agc
042876,000004: ## Purpose: Part of the source code for Luminary 1A build 099.
042877,000005: ## It is part of the source code for the Lunar Module's (LM)
042878,000006: ## Apollo Guidance Computer (AGC), for Apollo 11.
042879,000007: ## Assembler: yaYUL
042880,000008: ## Contact: Hartmuth Gutsche <hgutsche@xplornet.com>.
042881,000009: ## Website: www.ibiblio.org/apollo.
042882,000010: ## Pages: 984-987
042883,000011: ## Mod history: 2009-05-24 HG Transcribed from page images.
042884,000012: ## 2016-12-17 RSB Proofed text comments with octopus/ProoferComments
042885,000013: ## and corrected the errors found.
042886,000014: ## 2017-03-13 RSB Comment-text fixes noted in proofing Luminary 116.
042887,000015: ## 2017-08-26 MAS Fixed comment-text errors found while transcribing Zerlina 56.
042888,000016: ##
042889,000017: ## This source code has been transcribed or otherwise adapted from
042890,000018: ## digitized images of a hardcopy from the MIT Museum. The digitization
042891,000019: ## was performed by Paul Fjeld, and arranged for by Deborah Douglas of
042892,000020: ## the Museum. Many thanks to both. The images (with suitable reduction
042893,000021: ## in storage size and consequent reduction in image quality as well) are
042894,000022: ## available online at www.ibiblio.org/apollo. If for some reason you
042895,000023: ## find that the images are illegible, contact me at info@sandroid.org
042896,000024: ## about getting access to the (much) higher-quality images which Paul
042897,000025: ## actually created.
042898,000026: ##
042899,000027: ## Notations on the hardcopy document read, in part:
042900,000028: ##
042901,000029: ## Assemble revision 001 of AGC program LMY99 by NASA 2021112-61
042902,000030: ## 16:27 JULY 14, 1969
042903,000031:
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Page 984 |
042905,000033: # NAME - LSPOS - LOCATE SUN AND MOON DATE - 25 OCT 67
042906,000034: # MOD NO. 1
042907,000035: # MOD BY NEVILLE ASSEMBLY SUNDANCE
042908,000036:
042909,000037: # FUNCTIONAL DESCRIPTION
042910,000038:
042911,000039: # COMPUTES UNIT POSITION VECTOR OF THE SUN AND MOON IN THE BASIC REFERENCE SYSTEM. THE SUN VECTOR S IS
042912,000040: # LOCATED VIA TWO ANGLES. THE FIRST ANGLE(OBLIQUITY) IS THE ANGLE BETWEEN THE EARTH EQUATOR AND THE ECLIPTIC. THE
042913,000041: # SECOND ANGLE IS THE LONGITUDE OF THE SUN MEASURED IN THE ECLIPTIC.
042914,000042: # THE POSITION VECTOR OF THE SUN IS
042915,000043: # -
042916,000044: # S = (COS(LOS), COS(OBL)*SIN(LOS), SIN(OBL)*SIN(LOS)), WHERE
042917,000045:
042918,000046: # LOS = LOS +LOS *T-(C *SIN(2PI*T)/365.24 +C *COS(2PI*T)/365.24)
042919,000047: # 0 R 0 1
042920,000048: # LOS (RAD) IS THE LONGITUDE OF THE SUN FOR MIDNIGHT JUNE 30TH OF THE PARTICULAR YEAR.
042921,000049: # 0
042922,000050: # LOS (RAD/DAY) IS THE MEAN RATE FOR THE PARTICULAR YEAR.
042923,000051: # R
042924,000052:
042925,000053: # LOS AND LOS ARE STORED AS LOSC AND LOSR IN RATESP.
042926,000054: # 0 R
042927,000055: # COS(OBL) AND SIN(OBL) ARE STORED IN THE MATRIX KONMAT.
042928,000056:
042929,000057: # T, TIME MEASURED IN DAYS (24 HOURS), IS STORED IN TIMEP.
042930,000058:
042931,000059: # C AND C ARE FUDGE FACTORS TO MINIMIZE THE DEVIATION. THEY ARE STORED AS ONE CONSTANT (CMOD), SINCE
042932,000060: # 0 1 2 2 1/2
042933,000061: # C *SIN(X)+C *COS(X) CAN BE WRITTEN AS (C +C ) *SIN(X+PHI), WHERE PHI=ARCTAN(C /C ).
042934,000062: # 0 1 0 1 1 0
042935,000063:
042936,000064: # THE MOON IS LOCATED VIA FOUR ANGLES. THE FIRST IS THE OBLIQUITY. THE SECOND IS THE MEAN LONGITUDE OF THE MOON,
042937,000065: # MEASURED IN THE ECLIPTIC FROM THE MEAN EQUINOX TO THE MEAN ASCENDING NODE OF THE LUNAR ORBIT, AND THEN ALONG THE
042938,000066: # ORBIT. THE THIRD ANGLE IS THE ANGLE BETWEEN THE ECLIPTIC AND THE LUNAR ORBIT. THE FOURTH ANGLE IS THE LONGITUDE
042939,000067: # OF THE NODE OF THE MOON, MEASURED IN THE LUNAR ORBIT. LET THESE ANGLES BE OBL,LOM,IM, AND LON RESPECTIVELY.
042940,000068:
042941,000069: # THE SIMPLIFIED POSITION VECTOR OF THE MOON IS
042942,000070: # -
042943,000071: # 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))
042944,000072:
042945,000073: # WHERE
042946,000074: # 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
042947,000075: # 0 R 0 1 0 1
042948,000076: # LON=LON +LON
042949,000077: # 0 R
042950,000078: # A , A , B AND B ARE STORED AS AMOD AND BMOD (SEE DESCRIPTION OF CMOD, ABOVE). COS(OBL), SIN(OBL)*SIN(IM),
042951,000079: # 0 1 0 1
042952,000080: # SIN(OBL), AND COS(OBL)*SIN(IM) ARE STORED IN KONMAT AS K1, K2, K3 AND K4, RESPECTIVELY. LOM , LOM , LON , LON
042953,000081: # ARE STORED AS LOMO, LOMR, LONO, AND LONR IN RATESP. 0 R 0 R
042954,000082: # THE THREE PHIS ARE STORED AS AARG, BARG, AND CARG(SUN). ALL CONSTANTS ARE UPDATED BY YEAR.
042955,000083:
042956,000084: # CALLING SEQUENCE
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Page 985 |
042958,000086: # CALL LSPOS. RETURN IS VIA CPRET.
042959,000087:
042960,000088: # ALARMS OR ABORTS
042961,000089: # NONE
042962,000090:
042963,000091: # ERASABLE INITIALIZATION REQUIRED
042964,000092: # TEPHEM - TIME FROM MIDNIGHT 1 JULY PRECEDING THE LAUNCH TO THE TIME OF THE LAUNCH (WHEN THE AGC CLOCK WENT
042965,000093: # TO ZERO). TEPHEM IS TP WITH UNITS OF CENTI-SECONDS.
042966,000094:
042967,000095: # TIME2 AND TIME1 ARE IN MPAC AND MPAC +1 WHEN PROGRAM IS CALLED.
042968,000096:
042969,000097: # OUTPUT
042970,000098: # UNIT POSITIONAL VECTOR OF SUN IN VSUN. (SCALED B-1)
042971,000099: # UNIT POSITIONAL VECTOR OF MOON IN VMOON. (SCALED B-1)
042972,000100:
042973,000101: # SUBROUTINES USED
042974,000102: # NONE
042975,000103:
042976,000104: # DEBRIS
042977,000105: # CURRENT CORE SET, WORK AREA AND FREEFLAG
042978,000106:
042979,000107: 04,3027 BANK 04
042980,000108: 15,2000 SETLOC EPHEM
042981,000109: 15,2000 BANK
042982,000110:
042983,000111: 15,3664 E5,1714 EBANK= VSUN
042984,000112: 15,3664 COUNT* $$/EPHEM
042985,000113: 15,3664 15,3664 LUNPOS EQUALS LSPOS
042986,000114:
042987,000115: 15,3664 54201 LSPOS SETPD SR
042988,000116: 15,3665 00001 0
042989,000117: 15,3666 20617 14D # TP
042990,000118: 15,3667 56371 TAD DDV
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The hand-written notation "in centisec B 42" appears to the right. |
042992,000120: 15,3670 01707 TEPHEM # TIME OF LAUNCH
042993,000121: 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. |
042995,000123: 15,3672 00031 STORE TIMEP # T IN DAYS
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The hand-written notation "∴ granularity ≈ 0.164 sec" appears to the right. |
042997,000125: 15,3673 77170 AXT,1 AXT,2
042998,000126: 15,3674 00000 0
042999,000127: 15,3675 00000 0
043000,000128: 15,3676 77614 CLEAR
043001,000129: 15,3677 00274 FREEFLAG # SWITCH BIT
043002,000130: 15,3700 77745 POSITA DLOAD
043003,000131: 15,3701 12004 KONMAT +2 # ZEROS
043004,000132: 15,3702 00027 STORE GTMP
043005,000133: 15,3703 40745 POSITB DLOAD DMP*
043006,000134: 15,3704 00031 TIMEP # T
043007,000135: 15,3705 12050 VAL67 +4,1 # 1/27 OR 1/32 OR 1/365
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Page 986 |
043009,000137: 15,3706 42661 SL DAD*
043010,000138: 15,3707 20211 8D
043011,000139: 15,3710 12046 VAL67 +2,1 # AARG
043012,000140: 15,3711 40756 SIN DMP* # SIN(T/27+PHI) OR T/32 OR T/365
043013,000141: 15,3712 12044 VAL67,1 # (A0**2+A1**2)**1/2 SIN(X+PHIA)
043014,000142: 15,3713 62015 DAD INCR,1 # PLUS
043015,000143: 15,3714 00027 GTMP # (B0**2+B1**2)**1/2 SIN(X+PHIB)
043016,000144: 15,3715 77771 DEC -6 B-14
043017,000145: 15,3716 00027 STORE GTMP # OR (C0**2+C1**2)**1/2 SIN(X+PHIC)
043018,000146: 15,3717 77614 BOFSET
043019,000147: 15,3720 00054 FREEFLAG
043020,000148: 15,3721 33703 POSITB
043021,000149: 15,3722 40745 POSITD DLOAD DMP*
043022,000150: 15,3723 00031 TIMEP # T
043023,000151: 15,3724 65747 RATESP,2 # LOMR,LOSR,LONR
043024,000152: 15,3725 42661 SL DAD*
043025,000153: 15,3726 20206 5D
043026,000154: 15,3727 65741 RATESP +6,2 # LOMO,LOSO,LONO
043027,000155: 15,3730 77625 DSU
043028,000156: 15,3731 00027 GTMP
043029,000157: 15,3732 10021 STORE STMP,2 # LOM,LOS,LON
043030,000158: 15,3733 63135 SLOAD INCR,2
043031,000159: 15,3734 00050 X2
043032,000160: 15,3735 77775 DEC -2 B-14
043033,000161: 15,3736 53015 DAD BZE
043034,000162: 15,3737 12026 RCB-13 # PLUS 2
043035,000163: 15,3740 33770 POSITE # 2ND
043036,000164: 15,3741 77644 BPL
043037,000165: 15,3742 33700 POSITA # 1ST
043038,000166: 15,3743 45345 POSITF DLOAD DSU # 3RD
043039,000167: 15,3744 00021 STMP # LOM
043040,000168: 15,3745 00025 STMP +4 # LON
043041,000169: 15,3746 65356 SIN PDDL # SIN(LOM-LON)
043042,000170: 15,3747 00021 STMP
043043,000171: 15,3750 65356 SIN PDDL # SIN LOM
043044,000172: 15,3751 00021 STMP
043045,000173: 15,3752 55546 COS VDEF # COS LOM
043046,000174: 15,3753 53521 MXV UNIT
043047,000175: 15,3754 12002 KONMAT # K1,K2,K3,K4,
043048,000176: 15,3755 02723 STORE VMOON
043049,000177: 15,3756 65345 DLOAD PDDL
043050,000178: 15,3757 12004 KONMAT +2 # ZERO
043051,000179: 15,3760 00023 STMP +2
043052,000180: 15,3761 65356 SIN PDDL # SIN LOS
043053,000181: 15,3762 00023 STMP +2
043054,000182: 15,3763 55546 COS VDEF # COS LOS
043055,000183: 15,3764 53521 MXV UNIT
043056,000184: 15,3765 12002 KONMAT
043057,000185: 15,3766 02715 STORE VSUN
043058,000186: 15,3767 77616 RVQ
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Page 987 |
043060,000188: 15,3770 77745 POSITE DLOAD
043061,000189: 15,3771 12004 KONMAT +2 # ZEROS
043062,000190: 15,3772 00027 STORE GTMP
043063,000191: 15,3773 77650 GOTO
043064,000192: 15,3774 33722 POSITD
043065,000193: 15,3775 77616 LUNVEL RVQ # TO FOOL INTEGRATION
043066,000194: 05,2000 SETLOC EPHEM1
043067,000195: 05,2000 BANK
043068,000196:
043069,000197: 05,3506 COUNT* $$/EPHEM
043070,000198: 05,3506 STMP EQUALS 16D
043071,000199: 05,3506 GTMP EQUALS 22D
043072,000200: 05,3506 TIMEP EQUALS 24D
043073,000201:
End of include-file LUNAR_AND_SOLAR_EPHEMERIDES_SUBROUTINES.agc. Parent file is MAIN.agc