timer issue

thanks for your reply and info
hes what im try to do, i want to move the servo for 8 hours, 0 to 180, then back to 0, in 15mills, then wait 16 hours trhen move 8 hours, its for a solar tracker ( a very crude one), im just mixed up in the timing.... and probaly a lot move, your sugestions , are all noted and i will try when i get home, thanks for your info
craig