Stellar Parallax

This interactive simulator explores Stellar Parallax in Astronomy & The Sky. Earth orbit angle vs nearby star wobble on fixed background; π = 1/d(pc) arcsec, exaggerated. Use the controls to change the scenario; watch the visualization and any graphs or readouts to connect the model with lectures, labs, and homework.

Who it's for: Suited to beginners and first exposure to the topic. Typical context: Astronomy & The Sky.

Key terms

  • stellar
  • parallax
  • stellar parallax
  • astronomy

How it works

**Parallax** is the annual **wobble** of a **nearby** star against **distant** background stars. With baseline **1 AU**, the **parallax angle** (in arcseconds) is **π = 1/d** when **d** is in **parsecs** — the definition of the parsec. This sim **exaggerates** the shift for teaching; real angles are **sub-arcsecond**. The **green** line is a schematic sight line from **Earth** to the **near** star; the **yellow** dot slides on an **ellipse** as Earth orbits.

Key equations

π (arcsec) = 1 / d(pc) · baseline 1 AU