Objective: Investigating the factors affecting parallax Lesson 14: Parallax Objective: Investigating the factors affecting parallax

Stars appear to be the same distance from Earth because they are too far away to detect actual distance Astronomers have developed a technique for measuring distances using parallax

Parallax A phenomenon in which an object appears to change positions against a background when viewed from two different positions Another form of indirect measurement

To use parallax you need to understand simple right triangles. All triangles containing a given angle, the ratio of the opposite and adjacent sides is the same. Known as tangent of the angle When you know the length of one side of a right triangle, you can compute the length of the other side using tangent.

Astrolabe An instrument used to make astronomical measurements, typically of the altitudes of celestial bodies, and in navigation for calculating latitude.