Arcturus is remarkable in other respects.

His proper motion is very considerable, so great in fact that since the time of Ptolemy the southerly motion (alone) of Arcturus has carried him over a space nearly half as great again as the moon's apparent diameter.

One might expect that so brilliant a star, apparently travelling at a rate so great compared with the average proper motions of the stars, must be comparatively near to us.

This, however, has not been found to be the case.

Arcturus is, indeed, one of the stars whose distance it has been found possible to estimate roughly.