MDMD(4)--- N.M.'s darn trouble w/Sirius

[Eric Alan Weinstein]

Our Neville isn't the only astronomer to have trouble
getting his obs. correct when it comes to the area of Sirius.


Sirius B was discovered in 1862 (not 1962) by Alvan Clark as he
was testing the new lens he'd made for Dearborn Observatory's 
18 1/2 inch refracting telescope. He at first thought he'd found a
defect in the lens, but he finally realized he'd discovered the 
companion star that had been suspected since 1844. From 1834 to
1844 F.W.Bessel had noticed a wavy irregularity in the motion of Sirius
against the background stars, and had concluded that it had an invisible
companion. The orbit of the proposed compainion had been calculated
 in 1851 by C.H.F.Peters. By 1910 astronomers began to realize that there
were a class of stars, eventually called white dwarfs, which were very small
 and dim, yet very massive, which meant they had to be incredibly dense. 
In 1915 the first spectrum of Sirius B was obtained by W.Adams at Mt.Wilson,
which is all that would have been needed to classify it as a white dwarf.

from   http://marlowe.wimsey.com/~rshand/streams/scripts/sirius.html
Eric Alan Weinstein
University of London
E.A.Weinstein at qmw.ac.uk