REFERENCE FRAME VISUALIZER

Azimuth-Elevation & Right Ascension-Declination Coordinate Systems

⬤ Azimuth-Elevation (Topocentric/ECEF)

Local horizon coordinate system centered on the observer. Rotates with Earth.

Azimuth (Az): Angle measured clockwise from North (0°→360°)
Elevation (El): Angle above horizon (0°=horizon, 90°=zenith)

Used for: Antenna pointing, satellite tracking from ground stations

⬤ Right Ascension-Declination (ECI/Inertial)

Celestial coordinate system fixed to the stars. Does NOT rotate with Earth.

Right Ascension (RA): Angle from vernal equinox (0h→24h)
Declination (Dec): Angle from celestial equator (±90°)

Used for: Star catalogs, orbital elements, deep space navigation

Target Position (Celestial)

Right Ascension (RA) 6h 0m (90°)

Eastward from Vernal Equinox (0h = 0°, 12h = 180°)

Declination (Dec) +45.0°

From celestial equator (-90° to +90°)

Target RA / Dec: 6h 0m / +45.0°

Computed Az / El: -- / --

Hour Angle: --

Visibility: --

Ground Station

Latitude 25.0°N

Longitude 55.0°E

Default: Dubai (25°N, 55°E)

Time & Sidereal

Local Sidereal Time (LST) 0h 0m

Determines which RA is on the meridian

Animation

1.0x

Animate Earth Rotation Animate Target (Sweep RA) Animate Satellite Orbit

Satellite Orbit

True Anomaly 0.0°

Inclination 45.0°

RAAN (Ω) 30.0°

Arg. Periapsis (ω) 0.0°

Eccentricity 0.10

Enable J2 Perturbation

Display Options

Orbit Path Satellite VNC Frame Az/El Horizon Dome Celestial Sphere (ECI) Cardinal Directions Zenith Marker Celestial Equator Earth Globe Target Pointer Background Stars World Capitals

Texture Overlays

NASA Blue Marble overlay

Source: NASA BMNG · MODIS Terra 2004

Credit: Reto Stöckli / NASA GSFC

Idle

Blue Marble Opacity 100%

Local file overlay (JP2/JPG/PNG)

No file loaded

Local File Opacity 100%

ECI Frame (Inertial)

X: Vernal Equinox (RA=0h)

Y: North Celestial Pole

Z: RA=6h direction

ENU Frame (Topocentric)

E: East (Az=90°)

N: North (Az=0°)

U: Up/Zenith (El=90°)

VNC Frame (Orbital)

V (X): Velocity direction

N (Y): Orbit normal (⊥ plane)

C (Z): Cross-track (V×N)

Objects

Orbit Path

Periapsis (Pe)

Apoapsis (Ap)

Ascending Node (Ω)

Satellite

Ground Station

AZIMUTH-ELEVATION

Az: 45.0°

El: 30.0°

RIGHT ASCENSION-DEC

RA: --

Dec: --