Why do most stars show no parallax angle?
d. They are so far away that we ca not measure the apparent shift against the background stars. You need a significant distance between the two lower points of the triangle to be able to triangulate properly. But Earth´s orbit provides only about 15 light-minutes, and the nearest – the very nearest – star is almost 4 light years away. You understand how that would make accurate measurements difficult over even bigger distances.
