Have done to control the device to a candlelight vigil me. Off 30min after sunrise and 30 minutes before sunset to enable the plan was. Unfortunately, the advertised feature is not available. You can set when programming the while, however, the update time is not dependent on sunrise or sunset. Only when one performs and stores the programming again, times are changing. I have all recorded times over IFTT.com and appended (Update: table was removed from Amazon). There you can see, that does not change the times.
