Just before were distracted by the effects of love potions and poisons, Ron unwraps a watch decorated with stars and planets. Could it be the same watch Dumbledore checked in the very beginning of PS/SS?
He took a golden watch from his pocket and examined it. It was a very odd watch. It had twelve hands but no numbers; instead, little planets were moving around the edge.
Were told in HBP the gift was from his parents, but, given the dropped box of chocolate cauldrons, he clearly wasn’t paying that much attention. If DD was planning his death, perhaps he wanted to pass on this important piece of equipment before he went. It would be like him to send it without any information besides “use it well.”
The watch may function as a miniature version of the heavens, so he can time his moves precisely the same heavens the centaurs watch so carefully. Consider these SS/PS quotes from the centaurs:
“Remember, Firenze, we are sworn not to set ourselves against the heavens. Have we not read what is to come in the movements of the planets?”and later,
“Good luck, Harry Potter,” said Firenze. “The planets have been read wrongly before now, even by centaurs. I hope this is one of those times.”
The whole thing gives me the impression of DD staring at the sky as if it were a clock, waiting for the moment when all the pieces fall into place to avoid the end of the universe.
Consider what Ron, Ginny, and Luna reported after they got separated in the DoM in OotP: (Pg 795) “Four of them chased us into a dark room full of planets, it was a very odd place, some of the time we were just floating in the dark…”
It would seem that the Ministry has their own, much larger, version of this clock, with Unspeakables trying to decipher what the centaurs and DD already know. Could that brief run-in foreshadow Ginny and/or Luna figuring out how to read Ron’s new watch?!