We have the impression that the position of the stars in the sky
is unchanging, but that isn't true. It is simply the case that most
of the stars are so far away from us that we do not notice their
relative motions in our short lifetimes. However, there are
exceptions.

61 Cygni, sometimes called "The Flying Star," is
one of those exceptions. This binary star system has the largest
apparent motion of any naked-eye star (the two stars are 5th
and 6th magnitudes, and so should be just barely visible in
a truly dark sky). Over the course of 1 year, which is
the time between the two frames of this animation, the star
system appears to move 5.2 arcseconds relative to the other stars
(for some idea of scale, this would mean it takes 61 Cygni
346 years to move the apparent width of the moon in the sky).

This system is close enough that 61 Cygni
was the first star system whose distance from earth was
measured (in 1838, Friedrich Bessell measured the distance
using the apparent shift against more distant stars as he
looked at 61 Cygni from two parts of earth's orbit; he calculated
the distance as 10.3 light years; the actual distance is 11.4
light years).

Note: to see the motion of 61 Cygni in this animation,
you will need to view the "original" size here.

Exposure: 1 minute x 10, repeated 13 months apart
Camera: SBIG STL-11000
Telescope: Hyperion 12.5"