Aspects of Gravitation in Astrophysics. This book is the first "Manifesto" of a new emergent branch of Astronomy at the quantum limit, also called Quantum Astronomy. In the first chapters the reader starts with a mathematical and observational approach to accretion and circumstellar disks used in classical astronomy, used as background. With the Intermediate Polar RW UMi and AB Aur, the reader faces the practical data acquisition and handling at the telescope with classical techniques. In the latest chapters are introduced and discussed the extension of these classical concepts and formalisms to those of quantum physics applied to Astronomy. This novel approach is described in the two first applications proposed already in 2000 with the "Quantum Mousetrap", an instrumental technique for the detection of gravitational waves, here introduced and explained to the reader. Then is proposed the application of Glauber correlation functions for the characterization of the quantum states of light to obtain new information encoded in the electromagnetic field. Glauber correlations and Quantum Entanglement will be the first steps towards a new revolution in modern Astronomy