The Trigonometric Parallax
Example:
Nearest star, a Centauri, has a
parallax of p = 0.76 arc seconds
d = 1/p = 1.3 pc = 4.3 LY
With ground-based
telescopes, we can measure parallaxes p ≥ 0.02 arc sec
=> d ≤ 50 pc
This method does not
work for stars farther away than about 50 pc (nearly 200
light-years).
