So last night we were out observing (through telescopes; the anthropology was merely accidental), and there were some guys in the shadows apparently smoking a controlled substance. Suddenly, they get on their motorcycles and clear out. Moments later we see a police car coming into the area. So, pace Hume, we saw cause and effect. Moreover, Hume's analysis of the phenomenology is incorrect. It was not the case that seeing the cause led to (caused?!) an expectant feeling in us, because we saw the cause—the police car—after seeing the effect. (Presumably, the smokers saw it before they cleared out.)
I also saw IC 1396, M 31, M 32, M 33, M 45, M 52, M 110, the Double Cluster, NGC 6940, NGC 6960, NGC 6992, NGC 7000, NGC 7009, NGC 7027, NGC 7235, NGC 7635, Uranus and Jupiter. Of these, the Veil Nebula was particularly impressive. I had never seen it before, nor had I seen any photos of it, so I didn't know exactly what I was looking for. I couldn't find it without a filter. Finally, I put an OIII filter on my finder scope, and it showed up as a faint and large arc. With the filter on the 13", then, it looked really nice—lots of complexity. That, too, is an effect—an effect of a supernova. But while I was in a position to know the Veil to be an effect, because it was labeled "SNR" (supernova remnant) in a catalog on my PDA, I did not see it as an effect, in the way I saw the guys leaving as an effect.