Having just spent time over in Northern Scotland in July, I can tell you that it was a little disconcerting to think that it was probably about 7 PM, and discover it was already 10 PM. None of us wore a watch, and it was interesting to see exactly how dependent we were on the position of the sun, to tell us when to stop for the day. Most restaurants and pubs quit serving food at 10, so we ended up eating rather odd dinners. The sun would not set until 9 PM and dusk seemed to last for about 2 or 3 hours. I remember thinking that even at midnight, it did not seem really dark enough to see many stars. At 10:32 AM 8/18/2005 -0600, you wrote:
Maybe Hogwarts is in the extreme north. Venus can actually be visible at midnight if you are far enough north and close the summer solstice.
From the latitude of Edmonton, AB Venus will about 1 degree above the horizon, and above 4 degrees if you go above 60 degrees latitude in the year 2007. Incidentally, Venus is visible in the daytime when it's not too close to the sun.
Ken