The distance to stars relatively near to the Earth can be measured using a method call parallax. As a simple demonstration of parallax, hold your finger about a foot (30 cm) in front of your face. Close or cover one eye and notice what is behind your finger. Then close or cover the other eye without moving your head. What is behind your finger will be something different. In Figure 1 the arrow appears to be in front of the ’2’ when the left eye is covered. When the right eye is covered, the arrow appears to be in front of the ’1’. The key to this measurement is the left and right eye are at different positions. This is what gives us depth perception. An astronomer might say the ’baseline’ of your measurement is the separation of your eyes.