As a matter of fact, Dawes, who was, like Burnham, blessed
with most acute vision, saw the companion with an instrument no larger
than this small one in my hand--one inch and three-tenths. Ward saw it
with an inch and one-quarter objective, and Dawson with so small an
aperture as one inch. T.T. Smith has seen it with a reflector stopped
down to one inch and one-quarter, while in the instrument still known
as the "great Dorpat reflector," it has been seen in broad daylight.
This historic telescope has, I believe, a twelve inch object glass,
but the difficulty of seeing in sunshine so minute a star is such that
the fact may fairly be mentioned here.
Another interesting feature is this. Objects once discovered, though
thought to be visible in large telescopes only, may often be seen in
much smaller ones. The first Herschel said truly that less optical
power will show an object than was required for its discovery. The
rifts, or canals, in the Great Nebula in Andromeda is a case in point,
but two better illustrations may be taken from the planets.
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