Our planet also changes positions. In six months, the Earth will go from one side of the sun to the other. This is a change in distance of almost 300 million kilometers, and it’s enough to cause a noticeable apparent position change for some of the nearest stars. In fact, parallax is an important tool for measuring the distance to these stars. (Here are the other ways to measure stellar distances.)
So, yes, constellations change—but not that much.
Finding Your Longitude
Here’s how to find your longitude with a clock and a star chart. Let’s start with the star chart. Suppose there is a star on that chart that will always be
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