I'm with Paul: the two terms can't really be differentiated until relatively recently. Use of a telescope doesn't really come into into it and using the dictionary definitions doesn't help too much. Like many dictionaries defn 2 is circular: an astronomer is one who studies an astronomony. True, but not very helpful. Defn 1 is not really much better: is keeping an accurate calendar of sufficient quality to predict return of comets, lunar eclipses and so forth sufficent to constitute 'scientific' even if accompanied by ritual sacrifices and so forth which are believed to be as important? It's a matter of taste, in the end. Probably the crucial distinction is whether human lives and planetary motion are thought to be independant, and that question wasn't even asked (as far as we know) until pretty recently.

As far as aboriginal dreams are concerned, that seems a pretty weak link to hang this particular chain on. As someone mentioned, the accuracy of the dream-information is one thing; also relevant is the number of things dreamed about that are not representative of things in the real world. (Bayes Theorem and all that.)