Page 634 - 89 history of astronomy_opt

ods of the heliometer and the camera can-
not otherwise be made absolute.
The number of stars down to the four-
teenth magnitude may be taken at about
30,000,000; and that of all the stars visible
in the greatest modern telescopes is proba-
bly about 100,000,000.
˜
NebulA and Star-clusters. –Our knowl-
˜
edge of nebulA really dates from the time
634