65.30 light-years away
Aldebaran
Which star is a spacecraft heading for, and why is it not part of the cluster it appears to sit in?
It marks the eye of the bull and appears to lead the V-shaped face of the Hyades. It is not part of that cluster at all; it merely stands in front of it.
A trick of alignment
The Hyades is the nearest open star cluster, a genuine family of stars formed together, roughly 150 light-years away. Aldebaran sits at about 65 light-years — less than half that distance, entirely unrelated, and coincidentally in the same direction.
It is a striking demonstration of what a flat sky costs you. Two objects can appear adjacent and be nowhere near each other, which is exactly the caveat printed under the plate in the light tool: the distances there are true, the arrangement around the circle is not a map of space.
Where Pioneer 10 is going
Aldebaran is an orange giant, an old star swollen to around forty times the Sun's diameter, cool enough to burn visibly orange to the naked eye.
Pioneer 10, which stopped transmitting in 2003, is drifting in its general direction. It will take roughly two million years to cover the distance, by which time neither the spacecraft's aim nor the star's position will be what they are now. The plaque bolted to its side was designed for whoever might eventually find it — a message with no expectation of delivery, and a reasonable emblem for anything travelling between stars.