Astronomy Is Written For Astronomers

I Shall Now Recall To Mind That The Motion Of The Heavenly Bodies Is Circular, Since The Motion Appropriate To A Sphere Is Rotation In A Circle.

Those Who Know That The Consensus Of Many Centuries Has Sanctioned The Conception That The Earth Remains At Rest In The Middle Of The Heavens As Its Center, Would, I Reflected, Regard It As An Insane Pronouncement If I Made The Opposite Assertion That The Earth Moves.

For A Traveler Going From Any Place Toward The North, That Pole Of The Daily Rotation Gradually Climbs Higher, While The Opposite Pole Drops Down An Equal Amount.

Although All The Good Arts Serve To Draw Man's Mind Away From Vices And Lead It Toward Better Things, This Function Can Be More Fully Performed By This Art, Which Also Provides Extraordinary Intellectual Pleasure.

The Earth Together With Its Surrounding Waters Must In Fact Have Such A Shape As Its Shadow Reveals, For It Eclipses The Moon With The Arc Of A Perfect Circle.