Velocity frame converter

Radial velocity: heliocentric, LSR, GSR, barycentric

About this tool

Convert radial velocity between common radio-astronomy frames along a fixed line of sight. Positive velocity means recession from the frame origin along the beam.

Frames

  • Barycentric — solar-system barycentre; Earth orbital term from a Meeus-style ephemeris at your JD.
  • Heliocentric — Sun at rest.
  • Dynamical LSR — solar motion with editable (U,V,W)⊙ in Galactic coordinates (IAU-style defaults).
  • LSRK — 20 km/s toward l=90°, b=0°.
  • GSR — 220 km/s toward l=90°, b=0° (circular-rotation model).

Custom apex replaces dynamical LSR when enabled. Precession between equinoxes is not applied; coordinates are treated as ICRS/J2000.