[raymo]

Star atlases are updated every 50 yrs to keep star and DSO positions
accurate for all practical purposes. We are now using atlases of Epoch 2000;
previously it was Epoch 1950.
Some "nearby" stars move enough for their change in position to be seen in
just a few years, such as the change in position of the stars of the bright double
Alpha Cent. which take 80yrs to orbit each other. [actually a triple, but for our present purposes the two bright members are
all we are concerned with].
raymo