I don't know if any of you have ever heard of Richard Alpert "Ram Dass", an ex harvard psychology professor who became a spiritual teacher. This video is a really great lecture by him, he even mentions the astral somewhere in the end. The video is two hour long but it's really worth the watch. https://www.youtube.com/watch?v=JMUUBepzHH0 (https://www.youtube.com/watch?v=JMUUBepzHH0)
This is a long and interesting lecture the professor is really good in his subject.
Video seems very interesting. I have seen half of the video and rest will watch it very soon.