For what could be more beautiful than the heavens which contain all beautiful things.

Astronomy is written for astronomers

The massive bulk of the earth does indeed shrink to insignificance in comparison with the size of the heavens.

I am aware that a philosopher's ideas are not subject to the judgment of ordinary persons, because it is his endeavour to seek the truth in all things, to the extent permitted to human reason by God.

For I am not so enamoured of my own opinions that I disregard what others may think of them.

Among the authorities it is generally agreed that the Earth is at rest in the middle of the universe, and they regard it as inconceivable and even ridiculous to hold the opposite opinion. However, if we consider it more closely the question will be seen to be still unsettled, and so decidedly not to be despised. For every apparent change in respect of position is due to motion of the object observed, or of the observer, or indeed to an unequal change of both.

For it is the duty of an astronomer to compose the history of the celestial motions through careful and expert study.