PROGRAM MANUAL
CELESTIALTRACK
PROFESSIONAL SKY SIMULATION AND TRACKING SYSTEM
CelestialTrack is a browser-based professional sky simulation and object tracking system for astronomers, radio operators, and deep-space observers at the Deep Space Exploration Society, Haswell CO. It provides real-time azimuth/elevation tracking of the Sun, Moon, and five planets with algorithms validated against published ephemeris data.
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QUICK START
- 1
Open Main TrackerOpen celestial_sim.html in any modern browser. Runs entirely client-side with no installation.
- 2
Verify StationPre-loaded for Deep Space Exploration Society (38.3809N, 103.1564W, 1400 m). Edit in left panel or use preset dropdown.
- 3
Read Current PositionsThe sky polar plot and AZ/EL chart update immediately. Data table shows real-time AZ, EL, rise/set times, and angular separations.
- 4
Run a SimulationClick PLAY. Adjust Speed slider (x1 to x86400). Set Timeframe window (1h to 30d) to control the chart span.
- 5
Open Horizon ViewClick HORIZON VIEW in header. Colorado panorama window opens and syncs automatically with every simulation tick.
- 6
Export DataClick EXCEL or PDF for instant snapshot export. Press LOG before playback to capture a full logged time series first.
TRY THIS - VENUS INFERIOR CONJUNCTION
Set sim date to October 24, 2026 04:00 UTC. Venus appears within 6.6 degrees of the Sun. Open Horizon View facing SW with Auto-Track to Venus enabled, then play at x3600 speed.
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INTERFACE LAYOUT
| ZONE | LOCATION | DESCRIPTION |
|---|
| Header Bar | Top strip | Station name, coordinates, mode indicator (LIVE/SIM), UTC clock, window-launch buttons. |
| Control Panel | Left 260px column | Observer station, time control, object toggles, display options. Scrollable. |
| Sky View | Centre top | Azimuthal polar projection. Horizon at outer edge, zenith at centre, North at top. |
| AZ/EL Chart | Right top | Time-series: elevation (upper) and azimuth (lower) vs UTC over the selected timeframe. |
| Data Table | Bottom strip | Tabular real-time data: positions, rise/set/transit, separations, RA/Dec. Horizontally scrollable. |
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OBSERVER STATION SETUP
| FIELD | DESCRIPTION | DEFAULT |
|---|
| Station Name | Label shown in header and exported reports. | Deep Space Exploration Society |
| Latitude | Decimal degrees. North positive, South negative. | 38.38085762710463 |
| Longitude | Decimal degrees. East positive, West negative. | -103.15636801714136 |
| Altitude (m) | Metres above sea level. | 1400 |
| Preset Locations | Dropdown: DSES, Phoenix, London, Tokyo, Sydney, Mexico City, Everest, South Pole. | - |
NOTE
Changing any coordinate clears trail history and forces full recompute from the new location. Rise/set times update immediately.
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TIME CONTROL
| CONTROL | DESCRIPTION |
|---|
| Date/Time field | Direct entry in local time. Internally converted to UTC for all calculations. |
| NOW | Resets simulation to current real UTC time and clears all trail history. |
| PLAY / PAUSE | Starts or pauses simulation playback. Header MODE changes to SIM while playing. |
| RESET | Equivalent to NOW - returns to current time and clears trails. |
| Speed Slider | 10 steps from x1 (real time) to x86400 (1 day per second). |
| Timeframe Window | Sets AZ/EL chart span: 1h, 6h, 12h, 24h, 7d, 30d. Always centred on NOW. |
SPEED REFERENCE
| STEP | MULTIPLIER | LABEL | TYPICAL USE |
|---|
| 0 | x1 | 1s/s | Near real-time monitoring |
| 1 | x5 | 5s/s | Slow playback |
| 2 | x10 | 10s/s | Hourly events |
| 3 | x30 | 30s/s | Half-hour steps |
| 4 | x60 | 1min/s | Default - daily arcs |
| 5 | x300 | 5min/s | Full day in 5 minutes |
| 6 | x600 | 10min/s | Fast daily cycles |
| 7 | x1800 | 30min/s | Week in 4 minutes |
| 8 | x3600 | 1h/s | Month overview |
| 9 | x86400 | 1d/s | Year in 6 minutes |
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CELESTIAL OBJECTS
Seven solar system bodies are tracked. Click any object row in the left panel to toggle it on or off independently.
SUN
MOON
VENUS
MARS
JUPITER
SATURN
MERCURY
| OBJECT | ALGORITHM | DEFAULT |
|---|
| Sun | Low-precision Meeus Ch.25 solar formula | ON |
| Moon | Truncated ELP2000 - 7-term longitude series (Meeus Ch.47) | ON |
| Venus | Meeus Table 31.a orbital elements + iterative Keplerian propagation | ON |
| Mars | Meeus Table 31.a orbital elements + iterative Keplerian propagation | ON |
| Jupiter | Meeus Table 31.a orbital elements + iterative Keplerian propagation | ON |
| Saturn | Meeus Table 31.a orbital elements + iterative Keplerian propagation | ON |
| Mercury | Meeus Table 31.a orbital elements + iterative Keplerian propagation | OFF |
DISPLAY OPTIONS
| OPTION | EFFECT |
|---|
| Show Trails | Historical motion paths on sky plot and AZ/EL chart. Last 200 samples per object. |
| Show Labels | Object name, AZ, and EL next to each marker on the sky plot. |
| Show Grid | Azimuth spokes, elevation rings, and UTC time grid lines on both charts. |
| Show Separations | Connecting lines between objects within 30 degrees, labelled with angular separation. |
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SKY VIEW - AZIMUTHAL PROJECTION
The centre panel shows the entire sky looking straight up. Centre = zenith (90 deg EL). Outer edge = horizon (0 deg EL). North at top.
| ELEMENT | DESCRIPTION |
|---|
| Zenith (ZEN) | Centre of plot - directly overhead at 90 degree elevation. |
| Horizon ring | Outer bright cyan circle - 0 degree elevation. |
| Elevation rings | Dashed rings at 30 and 60 degree elevation, labelled. |
| Azimuth spokes | Dashed lines every 30 degrees. N/E/S/W labelled at outer edge. |
| Object glows | Radial gradient sized proportionally to apparent brightness. |
| Below-horizon | Faint marker clamped to horizon ring edge with directional arrow. |
| Separation lines | Green dashed lines between objects within 30 degrees. Separation labelled at midpoint. |
| Motion trails | Colour-coded historical track. Opacity increases toward current position. |
MOUSE TOOLTIP
Hover anywhere on the sky plot to see the azimuth and elevation for that exact point.
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AZ/EL TIME CHART
Right panel showing elevation and azimuth over time. Divided into two sub-panels:
| SUB-PANEL | Y-AXIS | RANGE |
|---|
| Top - Elevation | Degrees elevation | -90 to +90. Horizon (0 deg) at centre highlighted with cyan line. |
| Bottom - Azimuth | Degrees azimuth | 0 (North) to 360. Track breaks at 0/360 boundary crossing. |
The orange dashed NOW line marks current simulation time. Coloured dots show each object's current value. Hover to see UTC timestamp at any x-position. Chart always centres on current simulation time as playback advances.
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REAL-TIME DATA TABLE
| COLUMN | DESCRIPTION |
|---|
| OBJECT | Object name with astronomical symbol and colour indicator. |
| AZIMUTH | Topocentric azimuth in degrees. 0=North, increasing clockwise. |
| ELEVATION | Topocentric elevation above true horizon. Negative = below horizon. |
| STATUS | VISIBLE (El>5), HORIZON (-5 to 5), or BELOW (El<-5). |
| RISE / SET / TRANSIT | UTC times computed by 2-minute sampling over 24h window. Accuracy plus or minus 2 minutes. |
| SEP: [OBJECT] | Angular separation in degrees. Green <5deg, amber 5-30deg, grey >30deg. |
| RA (h) / DEC (deg) | Right Ascension in decimal hours and Declination in decimal degrees. |
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EXCEL AND PDF EXPORT
| BUTTON | FUNCTION |
|---|
| LOG | Starts recording every simulation tick as a data row. Label turns green with row count while active. |
| CLEAR | Clears the accumulated log buffer and resets row counter to zero. |
| EXCEL | Exports a 3-sheet .xlsx workbook. Uses logged data if available, else auto-samples the current timeframe. |
| PDF | Exports an A3 landscape dark-theme PDF report. |
EXCEL - 3 SHEETS
| SHEET | CONTENTS |
|---|
| Sky Positions and Separations | Full time-series: DateTime, Object, AZ, EL, Status, Rise, Set, Transit, 6 separation columns, RA, Dec, station coords. |
| Current Snapshot | Single-moment summary of all active objects at current simulation time. |
| Separation Matrix | N by N angular separation grid between all active objects at current time. |
PDF - MULTI-PAGE REPORT
| PAGE | CONTENTS |
|---|
| Page 1 | Station header, current positions table, angular separation matrix. |
| Page 2+ | Time-series data up to 500 rows. All position and separation columns. |
| All pages | Footer: station name, coordinates, and page number. |
LOGGING WORKFLOW
Set start time. Press LOG. Press PLAY and let simulation run through your window. Press STOP. Click EXCEL or PDF. Result: one row per tick per active object for the full recorded session.
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HORIZON VIEW WINDOW
Separate browser window with Colorado mountain panorama and full atmospheric day/night rendering. Open via HORIZON VIEW button in the main tracker header.
SYNCHRONISATION
| CHANNEL | DESCRIPTION |
|---|
| postMessage API | Direct inter-window messaging with near-zero latency (same origin). |
| localStorage polling | Fallback every 200ms - works across tabs and file:// origins. |
DIRECTION CONTROLS
| BUTTON | CENTRE AZ | NOTES |
|---|
| N | 0 deg | Eastern Colorado high plains - flat horizon |
| NE / E / SE | 45 / 90 / 135 deg | Plains extending east; minimal mountain silhouette |
| S | 180 deg | Default - faces the Southern Rocky Mountains |
| SW | 225 deg | Best view of Sangre de Cristo and Spanish Peaks |
| W / NW | 270 / 315 deg | Western horizon; Pikes Peak region visible NW |
| 360 PANORAMA | Full wrap | All 360 degrees across canvas width. FOV slider inactive. |
The FOV slider adjusts the horizontal field of view from 30 degrees (telephoto) to 180 degrees (fisheye). Default 90 degrees.
Below-horizon indicators: when a tracked object is below the horizon and within the current FOV azimuth range, a downward arrow with the object name and depth appears below the horizon line.
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COLORADO MOUNTAIN SCENERY
A 4-layer artistically crafted silhouette representing the view from the DSES site near Haswell, CO, looking toward the Southern Rocky Mountains.
| LAYER | DEPTH | KEY FEATURES | MAX HEIGHT |
|---|
| Far ridgeline | Distant | Sangre de Cristo (SW 200-265), Spanish Peaks (S 170-210), Pikes Peak (NW 315-345), Wet Mountains (S-SE 150-190) | 5.5% of sky |
| Mid ridgeline | Middle | Larger, more detailed Sangre de Cristo and Spanish Peaks masses with surface texture | 9% of sky |
| Near foreground | Foreground | Closest dark jagged ridge in SW and S quadrant only | 12% of sky |
| Ground roll | Immediate | Rolling plains and mesas to the east (60-120 deg); gentle undulation everywhere else | 1.5% of sky |
Snow caps appear on the Sangre de Cristo and Spanish Peaks ranges during daylight and twilight. Mountain colours transition dynamically: blue-grey haze by day, deep indigo at twilight, near-black at night.
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DAY / NIGHT CYCLE
Six distinct lighting states driven by the Sun's elevation angle:
ASTRO TWILIGHT
-18 to -12 deg
NAUT. TWILIGHT
-12 to -6 deg
CIVIL TWILIGHT
-6 to 0 deg
ATMOSPHERIC EFFECTS
| EFFECT | DESCRIPTION |
|---|
| Sun glow | Large radial gradient. Radius and colour transition from white at altitude to orange-red near horizon. |
| Horizon haze | Semi-transparent warm overlay at horizon during daytime; blue-grey at night. |
| Star field | 800 procedurally positioned stars. Fade in from solar depression -3 deg; full at -15 deg. Bright stars have glint crosshairs. |
| Moon disc | Disc with radial glow. Fades proportionally when solar elevation exceeds 10 degrees. |
| Planet fade | Planets fade from solar elevation 5 degrees onward, simulating daytime visibility loss. |
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AUTO-TRACK SYSTEM
Auto-Track continuously centres the Horizon View on a selected celestial object as the simulation advances.
- 1
Select Target ObjectUse the dropdown next to the AUTO-TRACK checkbox: Sun, Moon, Venus, Mars, Jupiter, Saturn, or Mercury.
- 2
Check AUTO-TRACKLabel turns green. View immediately snaps to the object's current azimuth. Direction buttons deactivate.
- 3
Run the SimulationThe view centre follows the object automatically. Your FOV setting is preserved - only the centre azimuth changes.
TRACKING RETICLE
| ELEMENT | DESCRIPTION |
|---|
| Outer ring | Pulsing circle at 0.4 Hz - draws immediate attention to the tracked object. |
| Inner ring | Fixed 14px radius reference circle for precise centring. |
| Crosshair arms | Four line segments extending beyond the outer ring in cardinal directions. |
| Label | TRACKING [OBJECT] displayed above the reticle, also pulsing in brightness. |
To disable: click any direction button (N, NE, E, SE, S, SW, W, NW, or 360 PANORAMA), or uncheck the AUTO-TRACK checkbox directly. Manual direction selection always overrides auto-track.
SUGGESTED USE
Set simulation to October 2026. Enable Auto-Track to Venus. Play at x3600 speed. The Horizon View follows Venus as it descends toward the Sun, reaching 6.6 degree separation on October 24.
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ASTRONOMY ALGORITHMS
Based on Astronomical Algorithms by Jean Meeus, 2nd edition (1998). All computations use double-precision floating point.
COORDINATE PIPELINE - 7 STEPS PER OBJECT PER TICK
- 1
Julian DateUTC input converted to JD: JD = Unix_ms / 86400000 + 2440587.5. T (Julian centuries from J2000) = (JD - 2451545) / 36525.
- 2
Mean Orbital ElementsEach planet's J2000 elements (a, e, i, ascending node, longitude of perihelion, mean longitude) evaluated linearly in T from Meeus Table 31.a.
- 3
Kepler's EquationEccentric anomaly E solved by 10 Newton iterations. Converges to machine precision in all solar system cases.
- 4
Heliocentric Ecliptic XYZTrue anomaly and radius from E. Position vector rotated to J2000 ecliptic frame using inclination, ascending node, and argument of perihelion.
- 5
Geocentric PositionEarth's heliocentric XYZ computed separately (Meeus Ch.27) and subtracted to yield geocentric ecliptic rectangular vector.
- 6
Equatorial RA/DecGeocentric vector rotated by obliquity epsilon(T) = 23.4393 - 0.013004*T degrees to J2000 equatorial frame. RA and Dec extracted with atan2 / asin.
- 7
Topocentric AZ/ELGMST from JD. LST = GMST + observer longitude. Hour angle H = LST - RA. Standard spherical trig: sin(EL) = sin(lat)*sin(Dec) + cos(lat)*cos(Dec)*cos(H). AZ from cosine formula with quadrant correction.
J2000 KEPLERIAN ELEMENTS
| PLANET | a (AU) | e | i (deg) | Period (days) |
|---|
| Mercury | 0.38710 | 0.20564 | 7.005 | 87.97 |
| Venus | 0.72334 | 0.00677 | 3.395 | 224.70 |
| Earth | 1.00000 | 0.01671 | 0.000 | 365.25 |
| Mars | 1.52371 | 0.09339 | 1.850 | 686.97 |
| Jupiter | 5.20289 | 0.04839 | 1.304 | 4332.59 |
| Saturn | 9.53668 | 0.05386 | 2.486 | 10759.22 |
VERIFICATION
Venus inferior conjunction Oct 24, 2026: computed Sun-Venus separation = 6.59 degrees. Published EarthSky value = 6.6 degrees. Difference = 0.01 degrees.
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ACCURACY AND LIMITATIONS
POSITION ACCURACY 2020-2030
| OBJECT | TYPICAL ERROR | NOTES |
|---|
| Sun | <0.01 deg | Fully adequate for AZ/EL planning. |
| Moon | 0.3-0.5 deg | 7-term ELP2000 truncation. Full series would give <0.01 deg. |
| Venus | <0.2 deg | Verified against published inferior conjunction data. |
| Mars | <0.5 deg | High eccentricity (0.093) amplifies errors from ignored perturbations. |
| Jupiter | <0.3 deg | Slow orbit reduces sensitivity to higher-order terms. |
| Saturn | <0.4 deg | Similar to Jupiter. |
| Mercury | 0.5-1.0 deg | 88-day period amplifies any element error. |
KNOWN LIMITATIONS
| LIMITATION | EFFECT |
|---|
| No atmospheric refraction | Objects near horizon appear up to 0.5 deg lower than observed. Rise/set times off by ~2 min. |
| No light-time correction | Geometric positions only. Jupiter at 6 AU has ~50 min light delay. Error <0.1 deg. |
| No precession/nutation | Uses J2000 frame. Errors grow outside 1990-2030. |
| No topocentric parallax | Moon position is geocentric - up to ~1 deg error for nearby observers. |
| Rise/set accuracy | Plus or minus 2 minutes - 2 minute sampling, linearly interpolated. |
| No mutual perturbations | Jupiter-Saturn interaction not modelled. Outer planet accuracy may degrade over decades. |
NOT SUITABLE FOR
Occultation or transit contact timing, navigational sight reduction, or applications requiring sub-arcminute precision. Use JPL Horizons or full VSOP87 for those purposes.
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GLOSSARY
| TERM | DEFINITION |
|---|
| Azimuth (AZ) | Horizontal angle clockwise from True North. East=90, South=180, West=270 degrees. |
| Elevation (EL) | Vertical angle above the horizon. 0=horizon, 90=zenith, negative=below horizon. |
| Right Ascension (RA) | Celestial longitude measured eastward from the vernal equinox. Expressed in hours (0-24h). |
| Declination (Dec) | Celestial latitude. 0=celestial equator, +90=north celestial pole, -90=south pole. |
| Julian Date (JD) | Continuous day count from noon Jan 1, 4713 BC. J2000.0 = JD 2451545.0 = Jan 1.5, 2000 UTC. |
| GMST / LST | Greenwich / Local Mean Sidereal Time. Used to convert RA to local hour angle. |
| Hour Angle (HA) | Westward angle from meridian to object. HA = LST minus RA. Zero at transit. |
| Transit | Object crossing the meridian - moment of maximum daily elevation. |
| Conjunction | Two objects at the same (or near) right ascension - appearing close together in sky. |
| Inferior Conjunction | Inner planet (Mercury/Venus) passes between Earth and Sun. |
| Superior Conjunction | Inner planet passes behind the Sun from Earth's perspective. |
| Elongation | Angular separation between a planet and the Sun as seen from Earth. |
| Synodic Period | Time between successive same-type conjunctions. Venus synodic period is approximately 584 days. |
| Civil Twilight | Sun 0 to -6 degrees. Outdoor activities possible without artificial light. |
| Nautical Twilight | Sun -6 to -12 degrees. Horizon visible at sea; most stars visible. |
| Astronomical Twilight | Sun -12 to -18 degrees. Sky nearly dark for observing. |
| Astronomical Night | Sun below -18 degrees. Fully dark sky. |
| Ecliptic | Apparent annual path of the Sun across the celestial sphere. Planets stay within 7 degrees of the ecliptic. |
| Obliquity | Tilt of Earth's rotation axis, currently approximately 23.44 degrees. Causes seasonal declination variation. |
| VSOP87 | Variations Seculaires des Orbites Planetaires - high-accuracy planetary theory (Bretagnon and Francou, 1987). |
| Keplerian Elements | Six parameters describing an orbit: semi-major axis, eccentricity, inclination, ascending node, longitude of perihelion, mean longitude. |
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TIPS AND TRICKS
WATCHING VENUS INFERIOR CONJUNCTION - OCT 24, 2026
- Set sim date to October 10, 2026 to see Venus and Mercury together in the evening sky (WSW after sunset).
- Open Horizon View and face SW. Enable Auto-Track to Venus.
- Play at x3600 speed. Watch Venus descend rapidly toward the Sun over the next two weeks.
- On October 24 at 04:00 UTC, pause the simulation. The Sun-Venus separation badge shows approximately 6.6 degrees.
- Continue past October 24 to watch Venus re-emerge in the morning sky (East, before sunrise).
GENERAL TIPS
| TIP | DETAIL |
|---|
| Find a planet's rise direction | Check the AZ value when EL is near 0 degrees on the AZ/EL chart - that bearing is exactly where it rises. |
| Log a full observation night | Set time to local sunset, press LOG, play at x3600, stop at sunrise. Export gives minute-by-minute positions for the entire night. |
| Compare two sites | Open two browser tabs with different station coordinates. Rise/set times differ by longitude; AZ arcs differ by latitude. |
| Conjunction hunting | Set timeframe to 30 days and speed to x86400 (1 day per second). Watch separation badges cycle as planets approach and recede. |
| South Pole observing | Select South Pole preset. Circumpolar objects never set - watch them trace constant-elevation circles around the zenith. |
| DSES twilight timing | From the DSES site, astronomical twilight ends approximately 1.5 hours after sunset. |
| Print the PDF | Use your PDF reader's grayscale or colour-invert option for paper printing (the report uses a dark theme). |
| Zoom into a conjunction | In Horizon View, narrow FOV to 30-40 degrees and use Auto-Track on one of the objects. The tracked object holds the reticle while its companion drifts in frame. |