Sunwait
Sunrise/sunset utility for Windows Task Scheduler or cron.
Sunwait calculates sunrise or sunset times with civil, nautical, astronomical and custom twilights.
It is intended for use in home automation with Windows Task Scheduler or cron. Use it to turn lights on *before* it gets dark! The program can wait from invocation until the event specified on the command line occurs or it can return immediately indicating if it is day or night. It's best to schedule Sunwait to run a little before the earliest opportunity for the event to occur each year...