The ancient greek astronomers divided atar according to
their brightness. Till the invention of the telescope, the division was only of
six classes or magnitudes. Star of the first magnitudecwere the brightest , and
those of sixth were the faintest. Since the invention of the telescope , the
division has gone to more then twenty. There are about 22 star of the first
magnitude , that is, the brightest star. The brigtest star of all is Sirius,
which has a magnitude of -1.6, making it over 1000 times brighter then the
faintest star we can see with naked eye. The number of star increase as we go
down in magnitude. There are about 1,000,000,000 star of the 20th
magnitude.
