Location from harry-potter-deathly-hallows by
The tallest tower in Hogwarts, where Dumbledore was killed -- its shadow hangs over the entire war, a reminder of what was lost and what Snape sacrificed.
The Astronomy Tower is where Draco lowered his wand and Snape raised his. Where Dumbledore fell. The memory of that night -- the Dark Mark hovering above the tower, students staring up in horror -- defines everything that follows. The Elder Wand's allegiance changed here when Draco disarmed Dumbledore, setting in motion the chain that would ultimately defeat Voldemort.
A slender soaring tower with a crenellated parapet open to the sky. Telescopes on tripods. The wind is always stronger here. The view stretches past the lake, past the forest, into the dark Scottish highlands.
Also known as: the Astronomy Tower, Astronomy Tower