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Why did Friedrich Bessel choose 61 Cygni for a stellar parallax measurement?

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Diagram illustrating how astronomers calculate the distance to a star using parallax: Earth is shown in two positions on opposite sides of its orbit around the Sun, with lines extending to a nearby star X and further to distant background stars. The apparent shift in star X's position, measured as angle A, is used to determine its distance, with the baseline labeled as 186,000,000 miles. — Parallax Calculating stellar distances.

Friedrich Wilhelm Bessel chose 61 Cygni for his pioneering stellar parallax measurement primarily because the star was known to possess a relatively high velocity in the plane of the sky.12

By observing this high proper motion, Bessel inferred that the star was likely closer to Earth than others, making its annual parallax—the subtle, elliptical shift in position caused by Earth's orbit around the Sun—more perceptible. Using a heliometer designed by Joseph von Fraunhofer, Bessel successfully demonstrated this motion in 1838. After correcting for the star's velocity, he calculated a parallax of approximately one-third of a second of arc, which corresponds to a distance of about 10.3 light-years. This achievement provided the first accurate distance measurement to a star other than the Sun, placing our understanding of the universe on a sound scientific basis.12