Astral body referred to the essence of a person, manifested physically outside of the person's original body.
The astral body of a person left the physical body during an I-Ching trance if the 49th hexagram was cast during the ritual. The astral body then traveled forward or backward in time depending on what the person saw on the other side of the Doorway to the Infinite (700, 837, 872).
An astral body was only a spiritual projection of the original person. While they were able to interact physically in another time period, astral bodies were invulnerable to any harm as the person's real body remained in its proper time in the I-Ching trance (842).
An exception to the standard projection of an astral body occurred when vampire Barnabas Collins used the I-Ching in 1969. His astral body traveled back to 1897 and took control of his physical body in that time (701). Because he now had a host body in the past, Barnabas was not immune to danger (835).
Three people were shown projecting their astral body through the Doorway to the Infinite and into another time: Barnabas Collins (700) , Julia Hoffman (837), and Count Andreas Petofi (872), however Petofi was possessing the body of Quentin Collins at the time.