# Parallax

- Apparent shift of foreground objects with respect to the background due to a change in perspective
- Used to determine the distance of stars from the Earth
- Using trigonometry
- Observing shifts in the stars position in the sky from day to day
- Limited range of 150 parsecs due to current technology
- ~400 light years

- Provides proof that the Earth orbits the Sun

## Formula

- $D = \frac{1}{p}$
- $D$ is distance in parsecs
- $p$ is the parallax angle in arcseconds