Page 642 - 89 history of astronomy_opt

of his spectroscopic evidence.
The light of the nebulas is remarkably
actinic, so that photography has a specially
fine field in revealing details imperceptible
in the telescope. In 1885 the brothers Henry
photographed, round the star Maia in the
Pleiades, a spiral nebula 3’ long, as bright
on the plate as that star itself, but quite in-
visible in the telescope; and an exposure of
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