Source Code

These source-code files were transcribed from a printout in Don Eyles's personal collection, scanned by archive.org, and financially sponsored by Linden Sims. A team of volunteers performed the transcription and proof-reading. The scanned page images are available at the Virtual AGC Project website, as well as higher-quality (but much larger) images at the Virtual AGC Project's collection in the Internet Archive. Report any problems by creating "issues" at the Virtual AGC Project's GitHub Repository.

Notations on the program listing read, in part:

	GAP:  ASSEMBLE REVISION 56 OF AGC PROGRAM ZERLINA BY ZOROASTER
	9:12 OCT. 21,1970
Note that the date is the date of the printout, not the date of the program revision.

048955,000002:                                                                                                  ## Copyright:   Public domain.
048956,000003:                                                                                                  ## Filename:    LATITUDE_LONGITUDE_SUBROUTINES.agc
048957,000004:                                                                                                  ## Purpose:     A log section of Zerlina 56, the final revision of
048958,000005:                                                                                                  ##              Don Eyles's offline development program for the variable 
048959,000006:                                                                                                  ##              guidance period servicer. It also includes a new P66 with LPD 
048960,000007:                                                                                                  ##              (Landing Point Designator) capability, based on an idea of John 
048961,000008:                                                                                                  ##              Young's. Neither of these advanced features were actually flown,
048962,000009:                                                                                                  ##              but Zerlina was also the birthplace of other big improvements to
048963,000010:                                                                                                  ##              Luminary including the terrain model and new (Luminary 1E)
048964,000011:                                                                                                  ##              analog display programs. Zerlina was branched off of Luminary 145,
048965,000012:                                                                                                  ##              and revision 56 includes all changes up to and including Luminary
048966,000013:                                                                                                  ##              183. It is therefore quite close to the Apollo 14 program,
048967,000014:                                                                                                  ##              Luminary 178, where not modified with new features.
048968,000015:                                                                                                  ## Reference:   pp. 1124-1130
048969,000016:                                                                                                  ## Assembler:   yaYUL
048970,000017:                                                                                                  ## Contact:     Ron Burkey <info@sandroid.org>.
048971,000018:                                                                                                  ## Website:     www.ibiblio.org/apollo/index.html
048972,000019:                                                                                                  ## Mod history: 2017-07-28 MAS  Created from Luminary 210.
048973,000020:                                                                                                  ##              2017-08-28 MAS  Updated for Zerlina 56.
048974,000021: 

Page 1124

048976,000023:                                                                                                  #  SUBROUTINE TO CONVERT RAD VECTOR AT GIVEN TIME TO LAT,LONG AND ALT
048977,000024: 
048978,000025:                                                                                                  #  CALLING SEQUENCE
048979,000026: 
048980,000027:                                                                                                  #    L-1    CALL
048981,000028:                                                                                                  #    L             LAT-LONG
048982,000029:                                                                                                  #  SUBROUTINES USED
048983,000030: 
048984,000031:                                                                                                  #   R-TO-RP,ARCTAN,SETGAMMA,SETRE
048985,000032:                                                                                                  #  ERASABLE INIT. REQ.
048986,000033: 
048987,000034:                                                                                                  #    AXO,-AYO,AZO,TEPHEM (SET AT LAUNCH TIME)
048988,000035:                                                                                                  #  ALPHAV = POSITION VECTOR METERS B-29
048989,000036:                                                                                                  #    MPAC-- TIME  (CSECS B-28)
048990,000037:                                                                                                  #   ERADFLAG =1, TO COMPUTE EARTH RADIUS, =0 FOR FIXED EARTH RADIUS
048991,000038:                                                                                                  #   LUNAFLAG=0 FOR EARTH,1 FOR MOON
048992,000039:                                                                                                  #  OUTPUT
048993,000040: 
048994,000041:                                                                                                  #    LATITUDE IN LAT   (REVS. B-0)
048995,000042:                                                                                                  #    LONGITUDE IN LONG   (REVS. B-0)
048996,000043:                                                                                                  #  ALTITUDE IN ALT METERS B-29
048997,000044: 30,3761                                           BANK     30                                    
048998,000045: 13,2000                                           SETLOC   LATLONG                               
048999,000046: 13,2000                                           BANK                                           
049000,000047: 
049001,000048: 13,2347                                           COUNT*   $$/LT-LG                              
049002,000049: 13,2347  E4,1431                                  EBANK=   ALPHAV                                
049003,000050: 13,2347           40220        LAT-LONG           STQ      SETPD                                 
049004,000051: 13,2350           03674                                    INCORPEX                              
049005,000052: 13,2351           00001                                    0D                                    
049006,000053: 13,2352           24007                           STOVL    6D                                    #  SAVE TIME IN 6-7D FOR R-TO-RP
049007,000054: 13,2353           02032                                    ALPHAV                                
049008,000055: 13,2354           51406                           PUSH     ABVAL                                 #  0-5D= R FOR R-TO-RP
049009,000056: 13,2355           16070                           STODL    ALPHAM                                #  ABS. VALUE OF R FOR ALT FORMULA BELOW
049010,000057: 13,2356           24007                                    ZEROVEC                               #  SET MPAC=0 FOR EARTH,NON-ZERO FOR MOON
049011,000058: 13,2357           71414                           BOFF     COS                                   #  USE COS(0) TO GET NON-ZERO IN MPAC
049012,000059: 13,2360           01743                                    LUNAFLAG                              #  0=EARTH,1=MOON
049013,000060: 13,2361           26362                                    CALLRTRP                              
049014,000061: 13,2362           77624        CALLRTRP           CALL                                           
049015,000062: 13,2363           51644                                    R-TO-RP                               #  RP VECTOR CONVERTED FROM R B-29
049016,000063: 13,2364           77656                           UNIT                                           #  UNIT RP B-1
049017,000064: 13,2365           36032                           STCALL   ALPHAV                                #  U2= 1/2 SINL FOR SETRE SUBR BELOW
049018,000065: 13,2366           26546                                    SETGAMMA                              #   SET GAMMA=B2/A2 FOR EARTH,=1 FOR MOON
049019,000066: 13,2367           77624                           CALL                                           #   SCALED B-1
049020,000067: 13,2370           26556                                    SETRE                                 #  CALC RE METERS B-29
049021,000068: 13,2371           63545                           DLOAD    DSQ                                   
049022,000069: 13,2372           02032                                    ALPHAV                                
049023,000070: 13,2373           63525                           PDDL     DSQ                                   
049024,000071: 13,2374           02034                                    ALPHAV     +2                         
049025,000072: 13,2375           75415                           DAD      SQRT                                  

Page 1125

049027,000074: 13,2376           76405                           DMP      SL1R                                  
049028,000075: 13,2377           00011                                    GAMRP                                 
049029,000076: 13,2400           14021                           STODL    COSTH                                 #  COS(LAT) B-1
049030,000077: 13,2401           02036                                    ALPHAV     +4                         
049031,000078: 13,2402           34023                           STCALL   SINTH                                 #  SIN(LAT) B-1
049032,000079: 13,2403           26506                                    ARCTAN                                
049033,000080: 13,2404           15120                           STODL    LAT                                   #  LAT B0
049034,000081: 13,2405           02032                                    ALPHAV                                
049035,000082: 13,2406           14021                           STODL    COSTH                                 #  COS(LONG) B-1
049036,000083: 13,2407           02034                                    ALPHAV     +2                         
049037,000084: 13,2410           34023                           STCALL   SINTH                                 #  SIN(LONG) B-1
049038,000085: 13,2411           26506                                    ARCTAN                                
049039,000086: 13,2412           15122                           STODL    LONG                                  #  LONG. REVS B-0 IN RANGE -1/2 TO 1/2
049040,000087: 13,2413           02070                                    ALPHAM                                
049041,000088: 13,2414           77625                           DSU                                            #  ALT= R-RE METERS B-29
049042,000089: 13,2415           03673                                    ERADM                                 
049043,000090: 13,2416           35124                           STCALL   ALT                                   #  EXIT WITH ALT METERS B-29
049044,000091: 13,2417           03674                                    INCORPEX                              
049045,000092: 

Page 1126

049047,000094:                                                                                                  #  SUBROUTINE TO CONVERT LAT,LONG,ALT AT GIVEN TIME TO RADIUS VECTOR
049048,000095:                                                                                                  #  CALLING SEQUENCE
049049,000096: 
049050,000097:                                                                                                  #    L-1    CALL
049051,000098:                                                                                                  #    L             LALOTORV
049052,000099:                                                                                                  #  SUBROUTINES USED
049053,000100: 
049054,000101:                                                                                                  #   SETGAMMA,SETRE,RP-TO-R
049055,000102:                                                                                                  #  ERASABLE INIT. REQ.
049056,000103: 
049057,000104:                                                                                                  #    AXO,AYO,AZO,TEPHEM  SET AT LAUNCH TIME
049058,000105:                                                                                                  #    LAT-- LATITUDE  (REVS B0)
049059,000106:                                                                                                  #    LONG-- LONGITUDE  (REVS B0)
049060,000107:                                                                                                  #  ALT--ALTITUDE (METERS) B-29
049061,000108:                                                                                                  #    MPAC-- TIME  (CSECS B-28)
049062,000109:                                                                                                  #    ERADFLAG =1 TO COMPUTE EARTH RADIUS, =0 FOR FIXED EARTH RADIUS
049063,000110:                                                                                                  #   LUNAFLAG=0 FOR EARTH,1 FOR MOON
049064,000111:                                                                                                  #  OUTPUT
049065,000112: 
049066,000113:                                                                                                  #  R-VECTOR IN ALPHAV (METERS B-29)
049067,000114: 13,2420           40220        LALOTORV           STQ      SETPD                                 #  LAT,LONG,ALT TO R VECTOR
049068,000115: 13,2421           03674                                    INCORPEX                              
049069,000116: 13,2422           00001                                    0D                                    
049070,000117: 13,2423           34007                           STCALL   6D                                    #  6-7D= TIME FOR RP-TO-R
049071,000118: 13,2424           26546                                    SETGAMMA                              #  GAMMA=B2/A2 FOR EARTH,1 FOR MOON B-1
049072,000119: 13,2425           73545                           DLOAD    SIN                                   #                COS(LONG)COS(LAT) IN MPAC
049073,000120: 13,2426           01120                                    LAT                                   #       UNIT RP= SIN(LONG)COS(LAT)    2-3D
049074,000121: 13,2427           65275                           DMPR     PDDL                                  #  PD 2          GAMMA*SIN(LAT)       0-1D
049075,000122: 13,2430           00011                                    GAMRP                                 
049076,000123: 13,2431           01120                                    LAT                                   #          0-1D= GAMMA*SIN(LAT) B-2
049077,000124: 13,2432           65346                           COS      PDDL                                  #  PD4      2-3D=COS(LAT) B-1 TEMPORARILY
049078,000125: 13,2433           01122                                    LONG                                  
049079,000126: 13,2434           57356                           SIN      DMPR                                  #  PD 2
049080,000127: 13,2435           71525                           PDDL     COS                                   #  PD 4    2-3D=SIN(LONG)COS(LAT) B-2
049081,000128: 13,2436           01120                                    LAT                                   
049082,000129: 13,2437           71525                           PDDL     COS                                   #  PD 6     4-5D=COS(LAT) B-1 TEMPORARILY
049083,000130: 13,2440           01122                                    LONG                                  
049084,000131: 13,2441           55475                           DMPR     VDEF                                  #  PD 4    MPAC= COS(LONG)COS(LAT) B-2
049085,000132: 13,2442           41456                           UNIT     PUSH                                  #  0-5D= UNIT RP FOR RP-TO-R SUBR.
049086,000133: 13,2443           36032                           STCALL   ALPHAV                                #  ALPHAV +4= SINL FOR SETRE SUBR.
049087,000134: 13,2444           26556                                    SETRE                                 #  RE METERS B-29
049088,000135: 13,2445           43145                           DLOAD    BOFF                                  #  SET MPAC=0 FOR EARTH,NON-ZERO FOR MOON
049089,000136: 13,2446           24007                                    ZEROVEC                               
049090,000137: 13,2447           01743                                    LUNAFLAG                              
049091,000138: 13,2450           26452                                    CALLRPRT                              
049092,000139: 13,2451           77746                           COS                                            #  USE COS(0) TO GET NON-ZERO IN MPAC
049093,000140: 13,2452           77624        CALLRPRT           CALL                                           
049094,000141: 13,2453           55720                                    RP-TO-R                               #  EXIT WITH UNIT R VECTOR IN MPAC
049095,000142: 13,2454           16032                           STODL    ALPHAV                                
049096,000143: 13,2455           03673                                    ERADM                                 

Page 1127

049098,000145: 13,2456           74215                           DAD      VXSC                                  #  (RE + ALT)(UNIT R) METERS B-30
049099,000146: 13,2457           01124                                    ALT                                   
049100,000147: 13,2460           02032                                    ALPHAV                                
049101,000148: 13,2461           77772                           VSL1                                           #  R METERS B-29
049102,000149: 13,2462           36032                           STCALL   ALPHAV                                #  EXIT WITH R IN METERS B-29
049103,000150: 13,2463           03674                                    INCORPEX                              
049104,000151:                                                                                                  #  SUBROUTINE TO COMPUTE EARTH RADIUS
049105,000152: 
049106,000153:                                                                                                  #  INPUT
049107,000154: 
049108,000155:                                                                                                  #    1/2 SIN LAT IN ALPHAV +4
049109,000156: 
049110,000157:                                                                                                  #  OUTPUT
049111,000158: 
049112,000159:                                                                                                  #    EARTH RADIUS IN ERADM AND MPAC  (METERS B-29)
049113,000160: 
049114,000161: 13,2464           63545        GETERAD            DLOAD    DSQ                                   
049115,000162: 13,2465           02036                                    ALPHAV     +4                         #  SIN**2(L)
049116,000163: 13,2466           44352                           SL1      BDSU                                  
049117,000164: 13,2467           24005                                    DP1/2                                 #  COS**2(L)
049118,000165: 13,2470           44275                           DMPR     BDSU                                  
049119,000166: 13,2471           26505                                    EE                                    
049120,000167: 13,2472           24005                                    DP1/2                                 
049121,000168: 13,2473           75465                           BDDV     SQRT                                  
049122,000169: 13,2474           26501                                    B2XSC                                 
049123,000170: 13,2475           77622                           SR4R                                           
049124,000171: 13,2476           03673                           STORE    ERADM                                 
049125,000172: 13,2477           77616                           RVQ                                            
049126,000173: 
049127,000174:                                                                                                  #  THE FOLLOWING CONSTANTS WERE COMPUTED WITH A=6378166,B=6356784 METERS
049128,000175:                                                                                                  #  B2XSC= B**2 SCALED B-51
049129,000176:                                                                                                  #  B2/A2= B**2/A**2 SCALED B-1
049130,000177:                                                                                                  #  EE=(1-B**2/A**2) SCALED B-0
049131,000178: 13,2500           00446 00305  B2XSC              2DEC     .0179450689                            #  B**2 SCALED B-51
049132,000179: 
049133,000180: 13,2502  12,2004               DP1/2              =        XUNIT                                 
049134,000181: 13,2502           17711 05254  B2/A2              2DEC     .9933064884 B-1                        #  GAMMA= B**2/A**2 B-1
049135,000182: 
049136,000183: 13,2504           00155 25250  EE                 2DEC     6.6935116  E-3                        #  (1-B**2/A**2) B-0
049137,000184: 

Page 1128

049139,000186:                                                                                                  #  ARCTAN SUBROUTINE
049140,000187: 
049141,000188: 
049142,000189:                                                                                                  #  CALLING SEQUENCE
049143,000190: 
049144,000191:                                                                                                  #    SIN THETA IN SINTH B-1
049145,000192:                                                                                                  #    COS THETA IN COSTH B-1
049146,000193:                                                                                                  #    CALL ARCTAN
049147,000194: 
049148,000195:                                                                                                  #  OUTPUT
049149,000196:                                                                                                  #     ARCTAN THETA IN MPAC AND THETA B-0 IN RANGE -1/2 TO +1/2
049150,000197: 
049151,000198: 
049152,000199: 13,2506           77600        ARCTAN             BOV                                            
049153,000200: 13,2507           26510                                    CLROVFLW                              
049154,000201: 13,2510           63545        CLROVFLW           DLOAD    DSQ                                   
049155,000202: 13,2511           00023                                    SINTH                                 
049156,000203: 13,2512           63525                           PDDL     DSQ                                   
049157,000204: 13,2513           00021                                    COSTH                                 
049158,000205: 13,2514           77615                           DAD                                            
049159,000206: 13,2515           75454                           BZE      SQRT                                  
049160,000207: 13,2516           26534                                    ARCTANXX                              #  ATAN=0/0  SET THETA=0
049161,000208: 13,2517           40065                           BDDV     BOV                                   
049162,000209: 13,2520           00023                                    SINTH                                 
049163,000210: 13,2521           26541                                    ATAN=90                               
049164,000211: 13,2522           67542                           SR1      ASIN                                  
049165,000212: 13,2523           00025                           STORE    THETA                                 
049166,000213: 13,2524           50125                           PDDL     BMN                                   
049167,000214: 13,2525           00021                                    COSTH                                 
049168,000215: 13,2526           26530                                    NEGCOS                                
049169,000216: 13,2527           43545                           DLOAD    RVQ                                   
049170,000217: 13,2530           57545        NEGCOS             DLOAD    DCOMP                                 
049171,000218: 13,2531           43244                           BPL      DAD                                   
049172,000219: 13,2532           26536                                    NEGOUT                                
049173,000220: 13,2533           24005                                    DP1/2                                 
049174,000221: 13,2534           00025        ARCTANXX           STORE    THETA                                 
049175,000222: 13,2535           77616                           RVQ                                            
049176,000223: 
049177,000224: 13,2536           52025        NEGOUT             DSU      GOTO                                  
049178,000225: 13,2537           24005                                    DP1/2                                 
049179,000226: 13,2540           26534                                    ARCTANXX                              
049180,000227: 13,2541           75345        ATAN=90            DLOAD    SIGN                                  
049181,000228: 13,2542           11011                                    LODP1/4                               
049182,000229: 13,2543           00023                                    SINTH                                 
049183,000230: 13,2544           00025                           STORE    THETA                                 
049184,000231: 13,2545           77616                           RVQ                                            
049185,000232: 
049186,000233: 13,2546  12,2006               2DZERO             =        DPZERO                                
049187,000234: 

Page 1129

049189,000236:                                                                                                  #  ..... SETGAMMA SUBROUTINE .....
049190,000237:                                                                                                  #  SUBROUTINE TO SET GAMMA FOR THE LAT-LONG AND LALOTORV SUBROUTINES
049191,000238: 
049192,000239:                                                                                                  #   GAMMA = B**2/A**2 FOR EARTH (B-1)
049193,000240:                                                                                                  #   GAMMA = 1 FOR MOON (B-1)
049194,000241: 
049195,000242:                                                                                                  #  CALLING SEQUENCE
049196,000243:                                                                                                  #   L       CALL
049197,000244:                                                                                                  #   L+1            SETGAMMA
049198,000245: 
049199,000246:                                                                                                  #  INPUT
049200,000247:                                                                                                  #   LUNAFLAG=0 FOR EARTH,=1 FOR MOON
049201,000248: 
049202,000249:                                                                                                  #  OUTPUT
049203,000250:                                                                                                  #   GAMMA IN GAMRP  (B-1)
049204,000251: 
049205,000252: 13,2546           43145        SETGAMMA           DLOAD    BOFF                                  #  BRANCH FOR EARTH
049206,000253: 13,2547           26503                                    B2/A2                                 #  EARTH GAMMA
049207,000254: 13,2550           01743                                    LUNAFLAG                              
049208,000255: 13,2551           26554                                    SETGMEX                               
049209,000256: 13,2552           77735                           SLOAD                                          
049210,000257: 13,2553           24005                                    1B1                                   #  MOON GAMMA
049211,000258: 13,2554           00011        SETGMEX            STORE    GAMRP                                 
049212,000259: 13,2555           77616                           RVQ                                            
049213,000260: 13,2556                        GAMRP              =        8D                                    
049214,000261: 

Page 1130

049216,000263:                                                                                                  #  .....SETRE SUBROUTINE .....
049217,000264:                                                                                                  #  SUBROUTINE TO SET RE (EARTH OR MOON RADIUS)
049218,000265: 
049219,000266:                                                                                                  #  RE= RM FOR MOON
049220,000267:                                                                                                  #   RE= RREF FOR FIXED EARTH RADIUS OR COMPUTED RF FOR FISCHER ELLIPSOID
049221,000268: 
049222,000269:                                                                                                  #  CALLING SEQUENCE
049223,000270:                                                                                                  #   L       CALL
049224,000271:                                                                                                  #   L+1            SETRE
049225,000272: 
049226,000273:                                                                                                  #  SUBROUTINES USED
049227,000274:                                                                                                  #   GETERAD
049228,000275: 
049229,000276:                                                                                                  #  INPUT
049230,000277:                                                                                                  #   ERADFLAG=0 FOR FIXED RE, 1 FOR COMPUTED RE
049231,000278:                                                                                                  #   ALPHAV +4= 1/2 SINL IF GETERAD IS CALLED
049232,000279:                                                                                                  #   LUNAFLAG=0 FOR EARTH,=1 FOR MOON
049233,000280: 
049234,000281:                                                                                                  #  OUTPUT
049235,000282:                                                                                                  #   ERADM= 504RM FOR MOON (METERS B-29)
049236,000283:                                                                                                  #   ERADM= ERAD OR COMPUTED RF FOR EARTH (METERS B-29)
049237,000284: 
049238,000285: 13,2556           71220        SETRE              STQ      DLOAD                                 
049239,000286: 13,2557           00051                                    SETREX                                
049240,000287: 13,2560           10003                                    504RM                                 
049241,000288: 13,2561           71214                           BON      DLOAD                                 #  BRANCH FOR MOON
049242,000289: 13,2562           01703                                    LUNAFLAG                              
049243,000290: 13,2563           26573                                    TSTRLSRM                              
049244,000291: 13,2564           10001                                    ERAD                                  
049245,000292: 13,2565           45014                           BOFF     CALL                                  #  ERADFLAG=0 FOR FIXED RE,1 FOR COMPUTED
049246,000293: 13,2566           00742                                    ERADFLAG                              
049247,000294: 13,2567           26571                                    SETRXX                                
049248,000295: 13,2570           26464                                    GETERAD                               
049249,000296: 13,2571           37673        SETRXX             STCALL   ERADM                                 #  EXIT WITH RE OR RM METERS B-29
049250,000297: 13,2572           00051                                    SETREX                                
049251,000298: 13,2573           77214        TSTRLSRM           BON      VLOAD                                 #  ERADFLAG=0,SET R0=RLS
049252,000299: 13,2574           00702                                    ERADFLAG                              #          =1     R0=RM
049253,000300: 13,2575           26571                                    SETRXX                                
049254,000301: 13,2576           02021                                    RLS                                   
049255,000302: 13,2577           64446                           ABVAL    SR2R                                  #  SCALE FROM B-27 TO B-29
049256,000303: 13,2600           77650                           GOTO                                           
049257,000304: 13,2601           26571                                    SETRXX                                
049258,000305: 13,2602  0000051               SETREX             =        S2                                    

End of include-file LATITUDE_LONGITUDE_SUBROUTINES.agc.  Parent file is MAIN.agc