Yep, days are really getting on the long side now, it's still pretty much light at 9pm now where I live. Incidently Wunderground.com has Civil twilight as between 0-6 degrees below the horizon, nautical twilight as 6-12 degrees below the horizon and astronomical twilight as 12-18 degrees below the horizon. Meaning complete darkness is where the sun is anything below 18 below. Twilight I may be reading it wrong though!