Page:Popular Astronomy - Airy - 1881.djvu/212

198 small star, known by the name of No. 61, in the constellation of Cygnus. He found that the change in the place of that star, as viewed from E' or from E'", produced by parallax, is about $6⁄10$ of a second; and this corresponds to a distance of 660,000 times the radius of the earth's orbit, or 63,000,000,000,000 miles. Enormous as this distance is, I state it as my deliberate opinion, founded upon a careful examination of the whole of the process of observation and calculation, that it is ascertained with what may be called in such a problem, considerable accuracy.

The distance of the stars of the second magnitude, founded upon Struve's conclusions to which I have already alluded, is not far from two millions of times as great as the distance of the sun from the earth. In this determination I have much less confidence. The distance of Alpha Centauri, if reliance may be placed on the observation, is only two hundred thousand times as great as the distance of the sun from the earth.