This is a real shot in the dark, but even if the odds are low I figured I might as well put it out there. Recently a book I once seen has come to mind. I saw this years ago when I first learning magic and I couldn’t afford it at the time. Now I am having vague memories of it.
I remember it was some pdf or digital file (maybe sold as a course). It wasn’t on a major website (so it may have since been scrubbed from the Internet). I think the website distributed PDFs/courses, although it wasn’t necessarily an occult site. It had a preview of the texts it distributed.
The content was about the astral sight but it may have used different terminology for it. From the preview it had visualization exercises where you imagined the room you were in and a ring around you. It then had you expand and contract the ring. I think it had more ways of using that ring but that’s all I remember/that’s all that was in the preview. The exercises had some illustration.
Anyway this isn’t really important just a thing that popped into my head, but if anyone happens to know what I am talking about let me know.