Stellar parallax
Turn a star’s annual parallax into a distance in parsecs and light-years.
Your experiment
How it works
As Earth moves around the Sun, a nearby star appears to shift against distant background stars. The annual parallax is half of the total angular shift between opposite points in Earth’s orbit.
Read the field note ↗About this model
The standard small-angle parsec relation with exact input. The diagram exaggerates angles and compresses distances. Real measurements include uncertainty and corrections.
Stellar parallax: common questions
What is a parsec?
A parsec is the distance corresponding to one arcsecond of annual parallax, approximately 3.26 light-years.
Why are distant stars harder to measure?
Their parallax angles are smaller, so a fixed angular uncertainty represents a larger fraction of the measurement.
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