Thank you for starting this topic, Dave.
61 Cygni is the first star to which an accurate distance was determined (by Friedrich Bessel in 1838) so it is of historical interest in addition to being an attractive double star. Enjoyable even in smaller telescopes. I made observations of it with 10x50 and 7x50 binoculars in early July, reported in this (slightly off topic) Binocular forum post. The instruments must be mounted, and it is difficult in a 7x50 -- I found it necessary to wear my glasses because even mild astigmatism interferes with resolving it at such low magnification. (Well, non-IS instruments must be mounted. Canon 10x42L IS anyone?)
Although it is not difficult to resolve in mounted 10x50 binoculars, I personally find it more enjoyable at higher magnifications. It's a fine view with 15/16x instruments, and I observed it last night with an Oberwerk 100XL-SD at 28x while navigating to a nearby star field.
Bessel determined a distance of 10.4 LY, quite close to the currently understood distance of 11.4 light years. Observations of the star where made six months apart and the known diameter of the Earth's orbit was used to triangulate the distance based on precise parallax measurements. The size of the Earth's orbit had been accurately determined from observations of the transit of Venus in 1769, made by expeditions to different parts of the earth. Edmond Halley had suggested the idea in 1716.
61 Cygni was chosen for observation by Bessel due to its high proper motion (apparent change compared with stars in the same field of view) because it is one of the closer stars to our own solar system (thus Piazzi's Flying star).
Edited by Fiske, 31 July 2021 - 07:34 AM.