The general beautiful effect is then
lessened, but more details are seen. Still, it is hardly necessary
to seek for a very large telescope for any investigation of the
lunar surface. I very much doubt whether any one has ever seen
anything on the moon which could not be made out in a clear,
steady atmosphere with a six-inch telescope of the first class.
Next to the moon, Saturn is among the most beautiful of celestial
objects. Its aspect, however, varies with its position in its
orbit. Twice in the course of a revolution, which occupies nearly
thirty years, the rings are seen edgewise, and for a few days are
invisible even in a powerful telescope. For an entire year their
form may be difficult to make out with a small telescope. These
unfavorable conditions occur in 1907 and 1921. Between these
dates, especially for some years after 1910, the position of the
planet in the sky will be the most favorable, being in northern
declination, near its perihelion, and having its rings widely
open. We all know that Saturn is plainly visible to the naked eye,
shining almost like a star of the first magnitude, so that there
is no difficulty in finding it if one knows when and where to
look. In 1906-1908 its oppositions occur in the month of
September.
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