Speaking of which: a few years ago there was quite awesome astronomy course, which I didn't have time to finish in real-time, and the content was deleted as soon as the course ended. I liked it wa-ay better than any other astronomy-ish stuff they had (and still have) later: it was more about actually modelling the celestial sphere and understanding the movement of the planets, than vaguely speaking about contents of the universe. Does by any chance anyone know how I can try and find it somewhere else? All I remember is that the professor had long gray hair and beard, which isn't really google-able.