Satellite Orbits

Date: 1986

Type: Program

Platform(s): TS 2068

This program calculates and displays satellite orbital tracks in real time, supporting a catalog of amateur radio, weather, and space station satellites including OSCAR, RS, NOAA, METEOR, Shuttle, MIR, and Salyut 7. It uses Keplerian orbital elements (inclination, eccentricity, mean motion, RAAN, argument of perigee, mean anomaly) together with an iterative Kepler equation solver to compute satellite position in Earth-centered inertial coordinates, then transforms to topocentric azimuth and elevation for a configurable observer location (hardcoded to approximately Los Angeles). A companion machine code block loaded from “Sat-Bahn C” at address 56000 handles real-time clock reads via BCD-encoded PEEKs at addresses 63675–63677 and satellite ground-track plotting via RANDOMIZE USR calls to routines at 63000, 63679, and 63702. The program also computes Doppler shift for each satellite’s beacon frequency and determines whether the satellite is in sunlight or Earth’s shadow using solar position calculations.

Program Analysis

Program Structure

The program is organized into clearly delineated sections indicated by REM statements. The top-level flow is:

Lines 1–8: Initialization, machine code load, variable setup, observer location
Lines 10–48: Date/Julian day number setup subroutine
Lines 1200–1980: Epoch validation, sidereal time, orbital constants, rotation matrix allocation
Lines 2000–3499: Main orbital computation and display loop
Lines 3500–3830: Sub-menu handling (fast clock, protocol/logging, restart, screen copy)
Lines 4000–4210: Doppler shift formatting
Lines 4500–4650: Calendar (day rollover) subroutine
Lines 5000–5490: Real-time clock adjustment utility
Lines 6000–6999: Main menu, satellite selection, and sun/shadow calculation
Lines 8000–8600: Date/time entry, clock set, UDG definition
Lines 9000–9550: Satellite Keplerian element data
Line 9999: Save and restart

Machine Code Integration

A companion code block is loaded at line 3 with LOAD "Sat-Bahn C" CODE into address 56000. Several machine code entry points are used:

Address	Usage
63000	Called at line 2010 via `RANDOMIZE USR 63000` — likely clears or resets the map display area
63679	Called at lines 6 and 2010 via `RANDOMIZE USR 63679` — probable screen or map initialization
63702	Called at lines 3400 and 6070 via `RANDOMIZE USR 63702` — plots the satellite position on the map using coordinates previously POKEd into 63826/63827
63826–63827	POKEd with `XPOS` and `175-YPOS` before calling 63702; act as parameter passing for the plot routine
63675–63677	Real-time clock registers in BCD format: hours, minutes, seconds
63522, 63545	Coarse and fine clock rate adjustment values
63604, 63493	POKEd in fast-clock (time-lapse) mode to alter tick rate
63772	POKEd 201 (RET opcode) to disable an interrupt handler, then 0 to re-enable

The clock is read by PEEKing BCD-encoded bytes: INT (PEEK 63675/16) extracts the tens digit and PEEK 63675 - 16*I gives the units digit, converting BCD to decimal without string conversion.

Orbital Mechanics

The program implements a standard SGP-style two-body propagator with first-order secular perturbations. Key steps include:

Secular drift of RAAN (O) and argument of perigee (W) due to J2 oblateness, using the perturbation factor K2=9.95*((R0/A0)^3.5)/(E2*E2) at line 1970
Iterative Kepler equation solution (lines 2250–2370) using Newton-Raphson iteration: E=E-M5/R3, terminating when ABS(M5) < 1E-6
Construction of a 3×2 rotation matrix C() from RAAN, argument of perigee, and inclination (lines 2140–2210), stored in a DIM C(PI,2) array — notably using PI (evaluated as 3) as the first dimension
Rotation from orbital plane to Earth-centered inertial (ECI) frame (lines 2440–2460)
Conversion from ECI to Earth-fixed frame using Greenwich Sidereal Time (lines 2660–2750)
Topocentric transformation to azimuth and elevation for the observer site (lines 2980–3090)

Observer Location and Coordinate Transform

The observer location is set at line 8: latitude L9=34.1°, west longitude W9=118°, height H9=0 km — corresponding to the Los Angeles area. The geodetic-to-ECEF conversion at lines 1840–1850 applies an oblateness correction using flattening factor F=1/298.25 and computes the observer’s geocentric Cartesian coordinates X9, Y9, Z9. The parametric latitude correction uses ATN((1-F)^2*S9/C9).

Sun Position and Shadow Detection

The subroutine at line 6700 implements a full solar position calculation to determine whether the satellite is in sunlight or Earth’s shadow. It computes Julian Date, mean solar longitude WS, solar equation of center CS, solar declination DC, and Earth-Sun distance RE. The shadow check at line 6955 compares the angular separation between satellite and Sun against the combined umbra angles of Earth as seen from the satellite and Earth as seen from the Sun (DZ2). The result is displayed as either "Sun " or "Shadow" in string J$.

Map Projection

The satellite ground track is mapped to screen pixel coordinates at lines 3342–3344. Latitude is linearly scaled to Y: YPOS=(L5+60)*16/14+7.5, covering approximately ±60° latitude. Longitude is mapped with a scale factor of 0.88757143 pixels per degree. The wrap-around at 180° is handled by the conditional at line 3342: IF W5>180 THEN LET W5=180-W5, with separate left/right half-plane cases.

Display and Status Lines

Line 3320 builds a 34-character string Y$ containing azimuth (Az=), elevation (El=), and satellite status (sun/shadow). The degree symbol is provided by UDG character \a, defined in the subroutine at line 8500 using POKE USR "a" with DATA values for a degree-symbol bitmap. Line 3335 builds Z$ for sub-satellite point longitude/latitude and satellite name. These are printed to the lower screen (channel #1) and main screen respectively.

Doppler Calculation

The Doppler shift is computed at line 3450 as DS4=RSF/(300000/V-1), where V is the range-rate in km/s derived from successive range values R5 and SR1 (lines 3440–3445). The time interval between samples differs between normal mode (÷15) and fast-clock mode (÷120). Frequencies below 1 MHz are displayed in kHz; those ≥1 MHz are displayed in MHz (lines 4020–4110).

Satellite Database

Keplerian elements for 19 satellites are stored as assignment statements in the 9100–9550 range, organized by category:

OSCAR group: OSCAR 9, 10, 11, JAS 1 (OSCAR 12)
RS group: RS 5, RS 7, RS 8
Weather: NOAA 6, 7, 8, 9, METEOR 2-10, METEOR 2-11
Crewed/Space Station: Shuttle (3 orbital inclinations), MIR, Salyut 7
Current (line 9500): D1 Mission (Spacelab D1)

Each entry stores: epoch year Y2, epoch day T0, inclination I0, revolution number K0, mean anomaly M0, eccentricity E0, mean motion N0 (rev/day), argument of perigee W0, RAAN O0, and beacon frequency RSF in Hz.

Notable Techniques and Idioms

DIM C(PI,2) at line 1980 exploits the fact that PI evaluates to 3 in BASIC, creating a 3×2 matrix without using a numeric literal
NOT PI is used throughout as a concise way to produce 0 (false), since NOT of any non-zero value returns 0
The menu dispatch at line 6090 uses computed GO TO (6000+CH0*100), and similarly at lines 6190, 6290, 6390, 6490 — an efficient dispatch table idiom
String padding loops at lines 4015 and 4200 ensure fixed-width right-aligned numeric output by prepending spaces
The PROTOKOLL logging feature (lines 3491–3492) sends formatted passes to a printer at 30-second intervals using LPRINT
Time-lapse (Zeitraffer) mode is toggled at lines 3610–3620, altering machine code clock divisors via POKE to accelerate orbital simulation
Line 3498 detects when XPOS crosses 245–265 (off the right edge of the map) to trigger a display refresh via GO TO 2000, preventing map artifacts
The epoch age warning at line 1250 compares current date against epoch date using the approximation Y*366+day and alerts if elements are more than 2 months old

Bugs and Anomalies

Line 8520 DATA contains aa as a literal token in what should be numeric DATA — this is likely a tokenization artifact where the value 0 was intended at those positions in the UDG bitmap
Line 9451 contains a double colon :: after M0=318.4556, which is a harmless redundant statement separator
The calendar subroutine at lines 4510–4565 does not account for leap years; February is always treated as having 28 days
Line 3150: the azimuth quadrant corrections at lines 3150–3190 and 3220–3250 use non-standard sign conventions that may produce errors near the cardinal axes; specifically, line 3160 sets W5=-W5 when X>0 AND Y<0, which is inconsistent with the subsequent line 3170
Line 5495 references variable CHh (mixed case) but line 6055 reads chh — on this platform variable names are case-insensitive in BASIC, so this is not a runtime error

Content

Appears On

Image Gallery

Source Code
REM Satellitenflugbahnen
REM RESET  R.St. 3/1986
CLEAR 55999: LOAD "Sat-Bahn C"CODE 
LET D$=""
POKE 63772,201: LET T$="": LET ZEITRAFF=NOT PI: LET PROTOKOLL=NOT PI: LET TAGFLAG=NOT PI: LET SZEIT=NOT PI: LET XPOS=254: LET YPOS=174
GO SUB 8000: RANDOMIZE USR 63679: GO SUB 8500
REM L9=Lat., W9=Long. West, H9=High
LET L9=34.1: LET W9=118: LET H9=0
GO SUB 6000: CLS : LET DM=NOT PI: LET MN=1
LET YN=Y2: GO SUB 40
LET T0=T0+DN: GO TO 1200
LET TT1=YN: LET TT2=MN
IF TT2>2.5 THEN GO TO 46
LET TT1=TT1-1: LET TT2=TT2+12
LET DN=INT (365.25*(TT1-80))-INT ((1900+TT1)/100)+INT ((1900+TT1)/400)-16
LET DN=DN+DM+30*TT2+INT (.6*TT2-.3): RETURN 
LET YN=VAL D$(7 TO 8): LET MN=VAL D$(4 TO 5): LET DM=VAL D$( TO 2)
GO SUB 40
IF (Y2*366+T0+60)<(YN*366+DN) THEN PRINT AT 20,12;"ATTENTION !": PRINT "Kep. Elements old. than 2 months": BEEP .05,30: FOR i=1 TO 300: NEXT i
LET T1=YN-1: LET DE=INT (365.25*(T1-80))-INT (T1/100)+INT (T1/400+.75)+366
LET T1=(DE+29218.5)/36525: LET T1=6.6460656+T1*(2400.0513+T1*2.581E-5): LET SE=T1/24-YN
REM INITIALISIERUNG
LET G0=7.5369793E13
LET G1=1.00273791
LET P1=3.1415927
LET P2=2*P1
LET P0=P1/180
LET R0=6378.16: LET F=1/298.25
LET L8=L9*P0: LET S9=SIN (L8): LET C9=COS (L8): LET S8=SIN (-W9*P0): LET C8=COS (W9*P0): LET R9=R0*(1-(F/2)+(F/2)*COS (2*L8))+H9/1000
LET L8=ATN ((1-F)^2*S9/C9): LET Z9=R9*SIN (L8): LET X9=R9*COS (L8)*C8: LET Y9=R9*COS (L8)*S8
LET A0=((G0/(N0*N0))^(1/3))
LET E2=1-E0*E0
LET E1=SQR (E2)
LET Q0=M0/360+K0
IF LEN G$>11 THEN LET G$=G$( TO 11)
IF LEN G$<11 THEN FOR i=11 TO LEN G$ STEP -1: LET G$=G$+" ": NEXT i
LET K2=9.95*((R0/A0)^3.5)/(E2*E2): LET S1=SIN (I0*P0): LET C1=COS (I0*P0)
DIM C(PI,2)
REM Berechnungsschleife
LET FLAG=NOT PI: RANDOMIZE USR 63000: RANDOMIZE USR 63679: PRINT AT 0,1; INVERSE 1; BRIGHT 0;G$;"  ";D$;" "; INVERSE 0: POKE 63772,0
LET I=INT (PEEK 63675/16): LET H$( TO 3)=STR$ (I)+STR$ (PEEK 63675-16*I)+":"
LET I=INT (PEEK 63676/16): LET H$(4 TO 6)=STR$ (I)+STR$ (PEEK 63676-16*I)+":"
LET I=INT (PEEK 63677/16): LET H$(7 TO )=STR$ (I)+STR$ (PEEK 63677-16*I)
LET T=VAL (H$( TO 2))/24+VAL (H$(4 TO 5))/1440+VAL (H$(7 TO ))/86400+DN
LET O=O0-(T-T0)*K2*C1: LET S0=SIN (O*P0): LET C0=COS (O*P0): LET W=W0+(T-T0)*K2*(2.5*(C1*C1)-.5): LET S2=SIN (W*P0): LET C2=COS (W*P0)
LET C(1,1)=(C2*C0)-(S2*S0*C1)
LET C(1,2)=-(S2*C0)-(C2*S0*C1)
LET C(2,1)=(C2*S0)+(S2*C0*C1)
LET C(2,2)=-(S2*S0)+(C2*C0*C1)
LET C(PI,1)=(S2*S1): LET C(PI,2)=(C2*S1): LET Q=N0*(T-T0)+Q0: LET K=INT Q
LET M=(Q-K)*P2: LET E=M+E0*SIN M+.5*(E0*E0)*SIN (2*M)
LET S3=SIN E: LET C3=COS E: LET R3=1-E0*C3: LET M1=E-E0*S3: LET M5=M1-M
IF ABS (M5)<1E-6 THEN GO TO 2410
LET E=E-M5/R3: GO TO 2310
LET X0=A0*(C3-E0)
LET Y0=A0*E1*S3
LET R=A0*R3
LET X1=X0*C(1,1)+Y0*C(1,2)
LET Y1=X0*C(2,1)+Y0*C(2,2)
LET Z1=X0*C(3,1)+Y0*C(3,2)
LET G7=(T-DE)*G1+SE
LET G7=(G7-(INT G7))*P2
LET S7=-SIN G7
LET C7=COS G7
LET X=(X1*C7)-(Y1*S7)
LET Y=(X1*S7)+(Y1*C7)
LET Z=Z1
LET X5=X-X9
LET Y5=Y-Y9
LET Z5=Z-Z9
LET R5=SQR (X5*X5+Y5*Y5+Z5*Z5)
LET DZ=R0/R
LET DZ=57.3*(-ATN (DZ/SQR (-DZ*DZ+1))+P1/2)
LET Z8=(X5*C8*C9)+(Y5*S8*C9)+(Z5*S9)
LET X8=-(X5*C8*S9)-(Y5*S8*S9)+(Z5*C9)
LET Y8=(Y5*C8)-(X5*S8)
LET S5=Z8/R5
LET C5=SQR (1-S5*S5)
LET E9=(ATN (S5/C5))/P0
LET A9=(ATN (Y8/X8))/P0
LET B5=Z/R
LET L5=(ATN (B5/(SQR (1-B5*B5))))*57.3
LET W5=(ATN (Y/X))*57.3
IF X<0 THEN LET W5=180-W5
IF X>0 AND Y<0 THEN LET W5=-W5
IF X>0 AND Y>0 THEN LET W5=360-W5
IF X=0 AND Y>=0 THEN LET W5=270
IF X=0 AND Y<0 THEN LET W5=90
IF X8<0 THEN LET A9=A9+180
IF X8>0 AND Y8<0 THEN LET A9=360+A9
IF X8=0 AND Y8>=0 THEN LET A9=90
IF X8=0 AND Y8<0 THEN LET A9=270
GO SUB 6710
LET A9=INT (A9+.5): LET E9=INT (E9+.5)
DIM Y$(34): LET Y$( TO 6+LEN STR$ A9)="Az="+STR$ A9+"\a": LET Y$(11 TO 14+LEN STR$ E9)="El="+STR$ E9+"\a": LET Y$(21 TO )="Stat.: "+J$
PRINT AT 21,0;Y$
LET W5=INT (W5+.5): LET L5=INT (L5+.5)
DIM Z$(34): LET Z$( TO 10+LEN STR$ W5)="SSP: L="+STR$ W5+"\a": LET Z$(15 TO 17+LEN STR$ L5)="B="+STR$ L5+"\a": LET Z$(22 TO )="Sat.: "+F$
PRINT #1;AT 0,0;Z$
LET XALT=XPOS: LET YALT=YPOS: IF XALT<0 OR XALT>255 OR YALT<8 OR YALT>167 THEN LET XALT=254: LET YALT=174
LET YPOS=(L5+60)*16/14+7.5: IF W5>180 THEN LET W5=180-W5
IF W5>=0 THEN LET XPOS=114.5-W5*0.88757143
IF W5<0 THEN LET XPOS=114.5+(180+W5)*0.88757143
IF XPOS<0 OR XPOS>255 OR YPOS<8 OR YPOS>167 THEN POKE 63826,255: POKE 63827,0: GO TO 3400
POKE 63826,XPOS: POKE 63827,(175-YPOS)
RANDOMIZE USR 63702: PLOT BRIGHT 1;XALT,YALT
IF NOT FLAG THEN LET FLAG=1: GO TO 3480
IF NOT ZEITRAFF THEN LET V=(SR1-R5)/15: IF V=0 THEN LET V=.0001
IF ZEITRAFF THEN LET V=(SR1-R5)/120: IF V=0 THEN LET V=.0001
LET DS4=RSF/(300000/V-1)
GO SUB 4000
LET T$="Dist.: "+K$
IF RSF THEN LET T$=T$+"Beac: "+R$
BRIGHT 0: PRINT #1;AT 1,0;T$
LET SR1=R5
IF INKEY$<>"" THEN PRINT #1;AT 1,0;"  Fast-Clock Protokoll End Copy ": GO TO 3500
IF PROTOKOLL AND (SZEIT=0 OR ZEITRAFF) AND E9>=-2 THEN LPRINT : LPRINT D$+"  "+H$( TO 6)+"00   "+Y$( TO 19): LPRINT Z$( TO 21)+"  "+T$()
IF PROTOKOLL AND (SZEIT=48 AND NOT ZEITRAFF) AND E9>=-2 THEN LPRINT : LPRINT D$+"  "+H$( TO 6)+"30   "+Y$( TO 19): LPRINT Z$( TO 21)+"  "+T$()
IF (PEEK 63675=0) AND (NOT TAGFLAG) THEN GO SUB 4500
IF PEEK 63675<>0 THEN LET TAGFLAG=0
IF XPOS<245 THEN LET GELOESCHT=0
IF NOT ZEITRAFF THEN LET SZEIT=PEEK 63677: IF SZEIT<>0 AND SZEIT<>21 AND SZEIT<>48 AND SZEIT<>69 THEN GO TO 3496
IF ZEITRAFF THEN LET SZEIT=PEEK 63676: IF (SZEIT/2)<>INT (SZEIT/2) THEN GO TO 3497
IF (XPOS>245 AND XPOS<265) AND NOT GELOESCHT THEN LET GELOESCHT=1: GO TO 2000
GO TO 2040
REM Untermenue
PAUSE 0: LET I$=INKEY$
IF I$="F" OR I$="f" THEN GO TO 3600
IF I$="P" OR I$="p" THEN GO TO 3800
IF I$="E" OR I$="e" THEN GO TO 3700
IF I$="C" OR I$="c" THEN PRINT #1;AT 1,0;T$: POKE 23326,2: POKE 23325,3: POKE 23345,-16: COPY /: GO TO 3491
GO TO 3505
REM Zeitraffer
IF ZEITRAFF=0 THEN LET ZEITRAFF=1: LET FLAG=NOT PI: POKE 63604,199: POKE 63493,5: PRINT #1;AT 1,0;T$: GO TO 3491
IF ZEITRAFF=1 THEN LET ZEITRAFF=NOT PI: POKE 63604,71: POKE 63493,50: PRINT #1;AT 1,0;T$: GO TO 3491
REM NEUSTART
FOR I=1 TO 8: POKE (64000+I ),CODE (D$(I)): NEXT I
POKE 63604,71: POKE 63493,50: CLEAR 
DIM D$(8): FOR I=1 TO 8: LET D$(I)=CHR$ (PEEK (64000+I)): NEXT I
GO SUB 8400
GO TO 5
REM PROTOKOLL
IF PROTOKOLL=1 THEN LET PROTOKOLL=NOT PI: PRINT #1;AT 1,0;"         PROTOKOLL OFF",: GO TO 3491
IF PROTOKOLL=0 THEN LET PROTOKOLL=1: PRINT #1;AT 1,0;"         PROTOKOLL ON",: LPRINT : LPRINT "Objekt: ";G$
GO TO 3491
REM DOPPLER-FORMATIEREN
IF W5<0 THEN LET W5=ABS (W5)+180
LET DIF=ABS (W5-W9): IF DIF>180 THEN LET DIF=360-DIF
LET DZ1=(SIN (L9*P0))*(SIN (L5*P0))+(COS (L9*P0))*(COS (L5*P0))*(COS (DIF*P0))
LET DZ1=57.3*(-ATN (DZ1/SQR (1-DZ1*DZ1))+P1/2)
LET KM=111.31989*DZ1
LET KM=INT KM: LET K$=STR$ (KM)+"km "
IF LEN K$<8 THEN LET K$=" "+K$: GO TO 4015
IF RSF>=1000000 THEN GO TO 4100
LET FREQ=INT ((DS4+RSF)*10)/10
LET R$=STR$ (FREQ)+"KHz"
GO TO 4200
LET FREQ=(INT ((DS4+RSF)/100))/10000
LET R$=STR$ (FREQ)+"MHz"
IF LEN R$<11 THEN LET R$=" "+R$: GO TO 4200
RETURN 
REM KALENDER
LET DM=DM+1
IF MN=1 AND DM>31 THEN LET MN=2: LET DM=1
IF MN=2 AND DM>28 THEN LET MN=3: LET DM=1
IF MN=3 AND DM>31 THEN LET MN=4: LET DM=1
IF MN=4 AND DM>30 THEN LET MN=5: LET DM=1
IF MN=5 AND DM>31 THEN LET MN=6: LET DM=1
IF MN=6 AND DM>30 THEN LET MN=7: LET DM=1
IF MN=7 AND DM>31 THEN LET MN=8: LET DM=1
IF MN=8 AND DM>31 THEN LET MN=9: LET DM=1
IF MN=9 AND DM>30 THEN LET MN=10: LET DM=1
IF MN=10 AND DM>31 THEN LET MN=11: LET DM=1
IF MN=11 AND DM>30 THEN LET MN=12: LET DM=1
IF MN=12 AND DM>31 THEN LET MN=1: LET DM=1: LET YN=YN+1
IF DM<10 THEN LET D$( TO 3)="0"+STR$ (DM)+"."
IF DM>9 THEN LET D$( TO 3)=STR$ (DM)+"."
IF MN<10 THEN LET D$(4 TO 6)="0"+STR$ (MN)+"."
IF MN>9 THEN LET D$(4 TO 6)=STR$ (MN)+"."
LET D$(7 TO )=STR$ (YN)
LET TAGFLAG=1: PRINT AT 0,15; INVERSE 1; BRIGHT 0;D$
RETURN 
REM UHR STELLEN
CLS : PRINT "Adjustment of the Clock"
LET GROB=PEEK 63522: LET FEIN=PEEK 63545
PRINT '"Changes:"
PRINT AT 7,0;"Coarse adjustment:"
PRINT "     ";(6-INT (GROB*12)/10);" seconds per hour"
PRINT '"Fine adjustment:"
PRINT "     ";(0.08-INT (FEIN*2)/100);" seconds per hour"
PRINT AT 15,13;"Coarse"
PRINT "1...faster","2...slower"
PRINT AT 18,13;"Fine"
PRINT "9...faster","0...slower"
PRINT AT 21,5;"Spacebar = End"
PAUSE 0: LET I$=INKEY$
IF I$="2" AND GROB<255 THEN POKE 63522,(GROB+1)
IF I$="1" AND GROB>0 THEN POKE 63522,(GROB-1)
IF I$="0" AND FEIN<255 THEN POKE 63545,(FEIN+1)
IF I$="9" AND FEIN>0 THEN POKE 63545,(FEIN-1)
IF I$=" " THEN GO TO 9999
GO TO 5000
PRINT AT 21,0;"Please enter Choise ": LET CHh=CODE INKEY$-48: RETURN 
REM Hauptmenue
PAPER NOT PI: BORDER NOT PI: INK 7: BRIGHT NOT PI: CLS 
PRINT "      SATELLITE-GROUP"
PRINT AT 4,4;"1. OSCAR 9-12"
PRINT '"    2. RS-Satelliten"
PRINT '"    3. Weathersatellite"
PRINT '"    4. Space-Shuttle/-Station"
PRINT '"    5. News"
GO SUB 5495: LET ch0=chh
IF CH0<1 OR CH0>5 THEN GO TO 6055
CLS : FOR N=1 TO 40: NEXT N
LET RSF=NOT PI: LET GELOESCHT=NOT PI: POKE 63826,254: POKE 63827,0: RANDOMIZE USR 63702
GO TO (6000+CH0*100)
REM OSCAR
PRINT AT 0,4;"OSCAR-Satellites"
PRINT AT 4,4;"1...OSCAR 9"
PRINT '"    2...OSCAR 10"
PRINT '"    3...OSCAR 11"
PRINT '"    4...JAS 1 (OSCAR 12)"
GO SUB 5495: LET ch2=chh
IF CH2<1 OR CH2>4 THEN GO TO 6170
GO TO (9100+CH2*10)
REM RS
PRINT AT 0,4;"RS-Satellites"
PRINT AT 4,4;"1...RS 5"
PRINT '"    2...RS 7"
PRINT '"    3...RS 8"
GO SUB 5495: LET ch2=chh
IF CH2<1 OR CH2>3 THEN GO TO 6270
GO TO (9200+CH2*10)
REM Wettersatelliten
PRINT AT 0,4;"Weathersatellites"
PRINT AT 4,4;"1...NOAA 6"
PRINT '"    2...NOAA 7"
PRINT '"    3...NOAA 8"
PRINT '"    4...NOAA 9"
PRINT '"    5...METEOR 2-10"
PRINT '"    6...METEOR 2-11"
GO SUB 5495: LET ch2=chh
IF CH2<1 OR CH2>6 THEN GO TO 6370
GO TO (9300+CH2*10)
REM Shuttle/Salyut
PRINT AT 0,2;"Space-Shuttle/-Station"
PRINT AT 4,4;"1...Shuttle (Aequator)"
PRINT '"    2...Shuttle (50\a Inkl.)"
PRINT '"    3...Shuttle (Polar)"
PRINT '"    4...MIR"
PRINT '"    5...Salyut 7"
GO SUB 5495: LET ch2=chh
IF CH2<1 OR CH2>5 THEN GO TO 6470
GO TO (9400+CH2*10)
REM Aktuell
LET CH2=1
GO TO (9500+CH2*10)
REM Sonne/Schatten
LET YS=YN: LET MS=MN
IF MN<3 THEN LET YS=YN-1: LET MS=MN+12
LET JA=INT (YS/100): LET JB=2-JA+INT (JA/4)
LET JD=INT (365.25*YS)+INT (30.6001*(MS+1))+T-(INT T)+DM+1720994.5+JB
LET JE=INT (365.25*YS)+INT (30.6001*(MS+1))+DM+1720994.5+JB
LET TJ=(JD-2415020)/36525
LET TE=(JE-2415020)/36525
LET SD=.2769194+100.00214*TE+1.075E-06*TE*TE
LET SD=(SD-(INT SD))*24
LET SD=SD+(T-(INT T))*24.06571
IF SD>24 THEN LET SD=SD-24
LET LT=SD+(-W9/15)
LET LT=LT+24*(LT<0)-24*(LT>24)
LET WS=279.69668+36000.76892*TJ+.0003025*TJ*TJ
LET WS=(WS/360-INT (WS/360))*360
LET MU=358.47583+35999.04975*TJ-.00015*TJ*TJ-.0000033*TJ*TJ*TJ
LET MU=(MU/360-INT (MU/360))*360
LET RO=1.675104E-02-.0000418*TJ-1.26E-07*TJ*TJ
LET CS=(1.91946-.004789*TJ-.000014*TJ*TJ)*SIN (MU*P1/180)+(.020094-.0001*TJ)*SIN (MU*P1/90)+.000293*SIN (MU*P1/60)
LET WT=WS+CS
LET LR=WT+180
IF WT>180 THEN LET LR=WT-180
LET NS=MU+CS
LET UP=SIN (WT*P1/180)*0.91746859
LET DW=COS (WT*P1/180)
LET RS=ATN (UP/DW)*180/P1
IF UP>0 AND DW>0 THEN LET RS=RS
IF UP>0 AND DW<0 THEN LET RS=RS+180
IF UP<0 AND DW>0 THEN LET RS=RS+360
IF UP<0 AND DW<0 THEN LET RS=RS+180
LET RS=RS/15
LET HS=(LT-RS)*15
LET DC=.39780824*SIN (WT*P1/180)
LET DC=ATN (DC/SQR (1-DC*DC))*180/P1
LET LOM=HS+W9
LET LOM=LOM+(LOM<0)*360-(LOM>360)*360
LET RE=(149674000*(1.0000002*(1-RO*RO)/(1+RO*COS (NS*P1/180))))
LET DZ2=ACS (R0/RE)
LET SLAT=DC*P1/180
LET DZ2=DZ2+ACS (R0/R)
LET ZA4=ABS (LOM-W5): IF ZA4>180 THEN LET ZA4=ABS (360-ZA4)
LET ZA5=ABS (LOM-W9): IF ZA5>180 THEN LET ZA5=ABS (360-ZA5)
LET DZ3=ACS (SIN (L5*P1/180)*SIN SLAT+COS (L5*P1/180)*COS SLAT*COS (ZA4*P1/180))
LET DZ4=ACS (SIN (L9*P1/180)*SIN SLAT+COS (L9*P1/180)*COS SLAT*COS (ZA5*P1/180))
LET STOS=SQR (R*R+RE*RE-2*R*RE*COS DZ3)
LET J$="Sun  ": IF DZ4>(DZ2-(ACS (R0/R))) THEN LET J$="Shadow"
LET INSOL=(ASN ((RE*SIN DZ3)/STOS))*180/P1
IF DZ3<(P1/2) THEN LET INSOL=180-INSOL
LET FO=NOT PI: IF DZ3>=DZ2 THEN LET FO=1
LET F$="Sun  "
IF DZ3>DZ2 THEN LET F$="Shadow "
RETURN 
REM Uhr & Datum stellen
PAPER NOT PI: BORDER NOT PI: INK 7: CLS 
PRINT "  Adjust hour and date"
PRINT AT PI,0;"Date of observation","Date (DD.MM.YY):       ";
INPUT "Please enter date: ";I$
IF LEN I$=0 AND LEN D$<>0 THEN GO TO 8050
IF LEN I$<>8 THEN GO TO 8040
DIM D$(8): LET D$=I$
LET DM=VAL D$( TO 2): IF DM<1 OR DM>31 THEN GO TO 8040
LET MN=VAL D$(4 TO 5): IF MN<1 OR MN>12 THEN GO TO 8040
LET YN=VAL D$(7 TO 8): IF YN<84 THEN GO TO 8040
PRINT D$
PRINT AT 7,0;"Time of observation","Time (HH.MM.SS):       ";
INPUT "Please enter time: ";I$
IF I$="" THEN GO SUB 8400: PRINT H$: GO TO 8300
LET H$=I$: IF LEN I$<>8 THEN GO TO 8105
LET HH=VAL H$( TO 2): IF HH<0 OR HH>23 THEN GO TO 8110
LET MI=VAL H$(4 TO 5): IF MI<0 OR MI>59 THEN GO TO 8110
LET A$=H$( TO 2)+H$(4 TO 5)
PRINT H$
POKE 63675,VAL H$(1)*16+VAL H$(2)
POKE 63676,VAL H$(4)*16+VAL H$(5)
POKE 63677,VAL H$(7)*16+VAL H$(8)
RETURN 
REM AKTUELLE ZEIT LESEN
DIM H$(8): LET H$(1)=STR$ (INT (PEEK 63675/16))
LET H$(2 TO 3)=STR$ (PEEK 63675-16*VAL (H$(1)))+":": LET H$(4)=STR$ (INT (PEEK 63676/16)): LET H$(5 TO 6)=STR$ (PEEK 63676-16*VAL (H$(4)))+":"
LET H$(7)=STR$ (INT (PEEK 63677/16)): LET H$(8)=STR$ (PEEK 63677-16*VAL (H$(7)))
RETURN 
REM Grad-Zeichen definieren
RESTORE 8510: FOR f=0 TO 7
READ aa: POKE USR "a"+f,aa
DATA 24,36,aa,24,0,aa,aa,aa
RETURN 
REM Satellitendaten
REM G$=OBJEKTNAME
REM Y2=JAHR
REM T0=EPOCH ZEIT
REM I0=INKLINATION
REM K0=UMLAUFNUMMER
REM M0=MEAN ANOMALY
REM N0=MEAN MOTION
REM E0=EXZENTRIZITAET
REM W0=ARGUMENT DES PERIG.
REM O0=RAAN
REM RSF=BAKENFREQUENZ
REM OSCAR
REM OSCAR 9
LET G$="OSCAR 9": LET Y2=86: LET T0=66.43480683: LET I0=97.6517: LET K0=24542: LET M0=282.9868: LET E0=.0004096: LET N0=15.28154898: LET W0=77.1959: LET O0=65.6189: LET RSF=145825000
RETURN 
REM OSCAR 10
LET G$="OSCAR 10": LET Y2=86: LET T0=62.88133564: LET I0=26.1922: LET K0=2049: LET M0=333.879: LET E0=.6005656: LET N0=2.05853397: LET W0=91.0093: LET O0=91.8901: LET RSF=145810000
RETURN 
REM OSCAR 11
LET G$="OSCAR 11": LET Y2=86: LET T0=66.75676743: LET I0=98.161: LET K0=10754: LET M0=244.347: LET E0=.0014126: LET N0=14.62032819: LET W0=115.9196: LET O0=135.0944: LET RSF=145826000
RETURN 
REM JAS 1
LET G$="JAS 1": LET Y2=86: LET T0=225.396462: LET I0=50.0082: LET K0=7: LET M0=442.0484: LET E0=.0011644: LET N0=12.44378049: LET W0=221.0709: LET O0=251.4714: LET RSF=435795000
RETURN 
REM RS-SATELLITEN
REM RS 5
LET G$="RS 5": LET Y2=86: LET T0=67.18901475: LET I0=82.9555: LET K0=18570: LET M0=111.8447: LET E0=.0008304: LET N0=12.05051506: LET W0=248.1681: LET O0=161.5035: LET RSF=29450
RETURN 
REM RS 7
LET G$="RS 7": LET Y2=86: LET T0=59.66057011: LET I0=82.9628: LET K0=18535: LET M0=176.2727: LET E0=.0022375: LET N0=12.0869565: LET W0=183.8165: LET O0=159.6531: LET RSF=29501
RETURN 
REM RS 8
LET G$="RS 8": LET Y2=85: LET T0=274.03973838: LET I0=82.9531: LET K0=16636: LET M0=86.5464: LET N0=12.02955854: LET E0=.0017936: LET W0=273.3515: LET O0=250.3508: LET RSF=29502
RETURN 
REM WETTERSATELLITEN
REM NOAA 6
LET G$="NOAA 6": LET Y2=84: LET T0=303.3457992: LET I0=98.5465: LET K0=27694: LET M0=340.1805: LET N0=14.24787164: LET E0=.0012461: LET W0=19.986: LET O0=325.1564: LET RSF=137500000
RETURN 
REM NOAA 7
LET G$="NOAA 7": LET Y2=85: LET T0=71.65806892: LET I0=99.0862: LET K0=19177: LET M0=298.9786: LET N0=14.13145626: LET E0=.0014132: LET W0=61.2798: LET O0=52.4364: LET RSF=137620000
RETURN 
REM NOAA 8
LET G$="NOAA 8": LET Y2=85: LET T0=306.13057229: LET I0=98.6532: LET K0=13497: LET M0=320.2196: LET N0=14.22476506: LET E0=.0017597: LET W0=40.0275: LET O0=335.4894: LET RSF=137500000
RETURN 
REM NOAA 9
LET G$="NOAA 9": LET Y2=86: LET T0=55.45565659: LET I0=98.9826: LET K0=6193: LET M0=251.6804: LET N0=14.11410499: LET E0=.0016327: LET W0=108.6136: LET O0=13.9014: LET RSF=137500000
RETURN 
REM METEOR 2-10
LET G$="METEOR 2-10": LET Y2=83: LET T0=328.6205573: LET I0=81.1627: LET K0=373: LET M0=172.872: LET N0=14.21513391: LET E0=.009535: LET W0=187.1111: LET O0=168.9035: LET RSF=137400000
RETURN 
REM METEOR 2-11
LET G$="METEOR 2-11": LET Y2=84: LET T0=325.2762071: LET I0=82.5329: LET K0=1907: LET M0=115.5296: LET N0=13.83455366: LET E0=.0011853: LET W0=244.4623: LET O0=254.0746: LET RSF=137300000
RETURN 
REM RAUMFAEHRE/-STATION
REM SHUTTLE AEQUATOR
LET G$="SHUTTLE": LET Y2=84: LET T0=280.8534722: LET I0=27.2007: LET K0=23: LET M0=14.1415: LET N0=15.97849766: LET E0=.0010544: LET W0=346.2766: LET O0=73.828
RETURN 
REM SHUTTLE 50\a
LET G$="SHUTTLE": LET Y2=84: LET T0=281.84930555: LET I0=57.1942: LET K0=39: LET M0=17.6465: LET N0=16.16455877: LET E0=.0007995: LET W0=345.432: LET O0=69.1449
RETURN 
REM SHUTTLE POLAR
LET G$="SHUTTLE": LET Y2=84: LET T0=352.4229: LET I0=97: LET K0=55: LET M0=207.5436: LET N0=15.65978125: LET E0=.0008229: LET W0=152.4947: LET O0=330.3691
RETURN 
REM MIR
LET G$="MIR": LET Y2=86: LET T0=68.93390168: LET I0=51.6266: LET K0=286: LET M0=217.2731: LET N0=15.77905815: LET E0=.0005499: LET W0=142.8454: LET O0=27.1524: LET RSF=143625000
RETURN 
REM SALYUT 7
LET G$="SALYUT 7": LET Y2=85: LET T0=352.88110415: LET I0=51.6288: LET K0=0: LET M0=318.4556:: LET N0=15.720563652: LET E0=.000197: LET W0=41.6602: LET O0=82.9791: LET RSF=142420000
RETURN 
REM AKTUELL
LET G$="D1 Mission": LET Y2=85: LET T0=309.375: LET I0=56.98606: LET K0=89: LET M0=285.03636: LET N0=15.818037: LET E0=.00082953284: LET W0=317.773182: LET O0=168.307742: LET RSF=145550000
RETURN 
CLEAR : SAVE "Sat-Bahn" LINE 1: SAVE "Sat-Bahn C"CODE 56000,9100: RUN 4

Note: Type-in program listings on this website use ZMAKEBAS notation for graphics characters.