The opinions set forth by Copernicus, Kepler and Newton are designed by astronomers of the present day under the collective title of the Copernician system, and they believe that these three dogmas, systems and laws, distinct as they are from each other, proceed consequentially one from the other, that they mutually supplement each the other, and thus form a harmonious whole. That not one of these things rests upon actual observation or even probable and perceptible facts, and finally, that none of them can be observed or verified, but that they are all three creations of the imagination, must be clearly evident to any one who occupies himself at all with the study of nature and more especially with the study of the heavenly phenomena. When we say that astronomy is an earthly science, we mean to imply that the heaven and the phenomena there apparent cannot be studied otherwise than as seen from the earth. Therefore astronomy is not a heavenly science, it consists solely of such ideas as we are able to form, that which we see on the heaven. It is not astronomy that is grand, compared with the vast objects with which it deals it dwindles to insignificance, and we may say that to speak of it as being a science of the "heavenly mechanism," nay more of the "laws of the universe," is sheer nonsense. The _universe_ must be for us a mere term, which does not convey any tangible idea to our minds. As only a very small portion of the heavenly space and its contents is visible to our eyes, astronomy--whatever may be the magnifying power placed at its disposal--must be confined within the limits of our vision and can therefore be no more than a small fragment. In the positive sense of the word, astronomy is more especially a science of _observation_, which is its _only_, but real and successful power. It may be said that astronomy has raised observation to a science, and its immense importance becomes more and more prominent as the explicative science loses in value; which is the more easily accounted for by the fact that observation will finally bring about the overthrow of all untenable theories. We see the heaven as we fly along, the earth whirls us with itself through space, hence astronomy cannot make any drawing room experiment, it cannot reproduce any of the heavenly phenomena, it can do nothing but _observe_. If therefore the science of astronomy be more especially an observative science, that which it does not and cannot observe, must be for it as good as not existent. But astronomy may, in addition, be designated _the science of observation of the apparent things_, things as they seem to be, for it is unable to see or regard the heavenly phenomena otherwise than they present themselves to it. _Astronomy is not permitted to observe realities._