Changes

Parallax is also used by astronomers to estimate the distance to nearby stars. A photograph is taken of the star. Six months later the Earth is on the opposite side of the Sun and a second photograph is taken. This provides a baseline of twice the distance from the Earth to the Sun, i.e. 186 million miles. The change in the apparent position of the star can be used to calculate its distance. The angular displacement of the star, expressed in [[radian]]s is equal to the baseline divided by the distance to the star.

Parallax is also used by astronomers to estimate the distance to nearby stars. A photograph is taken of the star. Six months later the Earth is on the opposite side of the Sun and a second photograph is taken. This provides a baseline of twice the distance from the Earth to the Sun, i.e. 186 million miles. The change in the apparent position of the star can be used to calculate its distance. The angular displacement of the star, expressed in [[radian]]s is equal to the baseline divided by the distance to the star.