Final answer:
The local description of a star is related to the celestial coordinate system through celestial coordinates, namely Right Ascension and Declination. These coordinates allow for precise astronomical observations such as measuring stellar parallax, which is essential for determining distances to stars.
Step-by-step explanation:
The local description of a star in the sky is related to the celestial coordinate system through its celestial coordinates, which are analogous to latitude and longitude on Earth. Specifically, astronomers use Right Ascension (RA) and Declination (Dec) to pinpoint a star's location. To observe a particular star or galaxy, an astronomer can point their telescope to its celestial coordinates. This method is crucial for various astronomical activities including celestial navigation, star mapping, and measuring parallax.
Stellar parallax is an example of how celestial coordinates are practical. The Greeks attempted to observe stellar parallax by monitoring stars at different times of the year to detect shifts in position caused by Earth's orbital motion. However, they were unsuccessful because the distances were too vast for the small parallax shifts to be noticeable without precise instruments. Today, stellar parallax is a vital tool for measuring the distances to nearby stars.