Describing and Measuring Stars

How was the first accurate measurement of the distance to a star achieved?

In 1838 Friedrich Bessel adapted techniques used to measure the motions of stars to calculate the parallax of the star 61 Cygni. With that information, he was able to measure the distance to that star to within a few percent accuracy of the modern value. He calculated the distance to 61 Cygni to be about ten light-years, much farther than the distance between any objects in the solar system. Bessel’s discovery opened the door to the proper study of stars not just as points of light but as tangible objects in space.


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