# What is Stellar Parallax Astronomers use an effect called [parallax](http://en.wikipedia.org/wiki/Parallax) to measure distances to nearby stars. Parallax is the apparent displacement of an object because of a change in the observer's point of view. The video below describes how this effect can be observed in an everyday situation, as well as how it is seen and used for finding distances to stars. Another way to see how this effect works is to hold your hand out in front of you and look at it with your left eye closed, then your right eye closed. Your hand will appear to move against the background. This effect can be used to measure the distances to nearby stars. As the Earth orbits the Sun, a nearby star will appear to move against the more distant background stars. Astronomers can measure a star's position once, and then again 6 months later and calculate the apparent change in position. The star's apparent motion is called stellar parallax. TLDR; Stellar parallax is the shift in the point of observation which later can be applied to certain trigonometry and/or calculus formulas in order to calculate the distance of a celestial body. This method has been used by humans for many years to calculate the distance of stars. > By - Jahan Shah --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://jahan-shah.gitbook.io/stellar-parallax-simplified-approach/what-is-stellar-parallax.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.