Page 439 - Bodhayanti Parasparam Vol 1

ASTRAL BODY
the physical is the considered opinion of the investigators into spiritual life. In this sense the growth or distortion of the individual are perceived through the internal organ and not through the external organs.
It is possible to observe the astral form or project the astral form out of the physical body too. It is not possible to do the same with regard to the physical. Spatial and temporal limitations are much fewer than the physical in respect of the astral. It is because it can be the transmigrator from one body to another at death and does keep its individuality that it is possible also to deal with it in its dreams and deep sleep states through the astral.
The reason for much of the spiritual work to be done during the deep sleep of the abhyasi or the Samadhi condition or the deep dhyana shows that what real transformation can be done is only during the period of the astral life. The Upanishad calls the state as the condition that when one is at one with the Divine which is the self and substrate of its being. Further this capacity for the astral being to be called up anywhere and from anywhere or considered apart from its
physical being or becoming shows that is sarva-gata. 435