Side-Lights on Astronomy and Kindred Fields of Popular ScienceNewcomb, Simon
Science
Side-Lights on Astronomy and Kindred Fields of Popular Science
Newcomb, Simon
Astronomy; Compass; Flying-machines; Hyperspace; Learning and scholarship; Rain-making
Uranus and Neptune are so distant that telescopes of considerable size
and high magnifying power are necessary to show their disks. In small
telescopes they have the appearance of stars, and the observer has no
way of distinguishing them from the surrounding stars unless he can
command the best astronomical appliances, such as star maps, circles on
his instrument, etc. It is, however, to be remarked, as a fact not
generally known, that Uranus can be well seen with the naked eye if one
knows where to look for it. To recognize it, it is necessary to have an
astronomical ephemeris showing its right ascension and declination, and
star maps showing where the parallels of right ascension and
declination lie among the stars. When once found by the naked eye,
there will, of course, be no difficulty in pointing the telescope upon
it.
Of celestial objects which it is well to keep a watch upon, and which
can be seen to good advantage with inexpensive instruments, the sun may
be considered as holding the first place. Astronomers who make a
specialty of solar physics have, especially in this country, so many
other duties, and their view is so often interrupted by clouds, that a
continuous record of the spots on the sun and the changes they undergo
is hardly possible. Perhaps one of the most interesting and useful
pieces of astronomical work which an amateur can perform will consist
of a record of the origin and changes of form of the solar spots and
faculae. What does a spot look like when it first comes into sight?
Does it immediately burst forth with considerable magnitude, or does it
begin as the smallest visible speck, and gradually grow? When several
spots coalesce into one, how do they do it? When a spot breaks up into
several pieces, what is the seeming nature of the process? How do the
groups of brilliant points called faculae come, change, and grow? All
these questions must no doubt be answered in various ways, according to
the behavior of the particular spot, but the record is rather meagre,
and the conscientious and industrious amateur will be able to amuse
himself by adding to it, and possibly may make valuable contributions
to science in the same way.
Public-domain text, read in full here on John Shaqi.
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