Question

what is parallax method

Answer 1

Parallax is a method of measuring distance to an object. Similar to how our binocular vision helps us determine distance, the direction to a distant point is slightly different from two separate observation positions. If the distance between the observation positions is known, and the angle between them can be measured, it is a matter of simple geometry to calculate the distance to the object. It is a relatively simple concept but is one of the most important for making astronomical observations.