An introduction to astronomy: designed as a text-book for the use of students in college. By Denison Olmsted ...

PREI:,INARY OBSERVATIONS. 3
4. Astronomers of every age have been distinguished for
their persevering industry, and their great love of accuracy.
They have uniformly aspired to an exactness in their inquiries
far beyond what is aimed at in most geographical investigations, satisfied with nothing short of numerical accuracy,
wherever this is attainable; and years of toilsome observation,
or laborious calculation, have been spent with the hope of attaining a few seconds nearer to the truth. Moreover, a severe
but delightful labor is imposed on all who would arrive at a
clear and satisfactory knowledge of the, subject of astronomy.
Diagrams, artificial globes, orreries, and familiar comparisons
and illustrations, proposed by the author or the instructor, may
afford essential aid to the learner, but nothing can convey to
him a perfect, comprehension of the celestial motions, without
much diligent study and reflection.
5. In expounding the doctrines of astronomy, we do not, as
in geometry, claim that every thing shall be proved as soon as
asserted. W'e may first put the learner in possession of the
leading facts of the science, and afterwards explain to him the
methods by which those facts were discovered, and by which
they may be verified; we may assume the principles of the
true system of the world, and employ those principles in the
explanation of many subordinate phenomena, while we reserve
the discussion of the merits of the system itself, until the
learner is extensively acquainted with astronomical facts, and
therefore better able to appreciate the evidence by which the
system is established.
6. The C'opernican System is that which is held to be the
true system of the world. It maintains (1), That the apjc)arent
diurnal revolution of the heavenly bodies, from east to west, is
owing to the real revolution of the earth on its own axis froml
west to east, in the same time; and (2), That the sun is the
center around which the earth and planets all revolve fiom
west to east, contrary to the opinion that the earth is the center
of motion of the sun and planets.
7. We shall treat, first, of the Earth in its astronomical
relations; secondly, of the Solar System; and, thirdly, of the
Fixed Stars.