Thomas Henderson (1798-1844) had indeed measured the larger displacements of a Centauri at the Cape in 1832-1833, but delayed until 1839 to publish his result.
Thesun's nearest neighbour is a Centauri, which is separated from it by 270,000 times the earth's distance, a space which it would take light four years to traverse.
Several estimates have been made which agree well together; whether direct use is made of known parallaxes, or comparison is made with binaries of well-determined orbits of the same spectral type as the sun, in which therefore it may be assumed there is the same relation between mass and brilliancy (Gore), the result is found that the sun's magnitude is - 26.5, or the sun is Io n times as brilliant as a first magnitude star; it would follow that the sun viewed from a Centauri would appear as of magnitude 0.7, and from a star of average distance which has a parallax certainly less than o 1 ", it would be at least fainter than the fifth magnitude, or, say, upon the border-line for naked-eye visibility.
Gellius and Ausonius state that he composed an Erotopaegnia, and in other sources he is credited with Adonis, Alcestis, Centauri, Helena, Ino, Protesilaudamia, Sirenocirca, Phoenix, which may, however, be only the parts of the Erotopaegnia.
The Hercules cluster is of this form; another example is Centauri, in which over 6000 stars have been counted, comprised within a circle of about 40' diameter.